Cialis vs Viagra – An In-Depth Comparison
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Sildenafil
Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Sildenafil (Revatio) is used to improve the ability to exercise in adults with pulmonary arterial hypertension (PAH; high blood pressure in the vessels carrying blood to the lungs, causing shortness of breath, dizziness, and tiredness). Children should not usually take sildenafil, but in some cases, a doctor may decide that sildenafil (Revatio) is the best medication to treat a child’s condition. Sildenafil is in a class of medications called phosphodiesterase (PDE) inhibitors. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. This increased blood flow can cause an erection. Sildenafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow easily.
If you are taking sildenafil to treat erectile dysfunction, you should know that it does not cure erectile dysfunction or increase sexual desire. Sildenafil does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus (HIV).
How should this medicine be used?
Sildenafil comes as a tablet and suspension (liquid; Revatio only) to take by mouth.
If you are taking sildenafil to treat erectile dysfunction, follow your doctor’s directions and the guidelines in this paragraph. Take sildenafil as needed before sexual activity. The best time to take sildenafil is about 1 hour before sexual activity, but you can take the medication any time from 4 hours to 30 minutes before sexual activity. Sildenafil usually should not be taken more than once every 24 hours. If you have certain health conditions or are taking certain medications, your doctor may tell you to take sildenafil less often. You can take sildenafil with or without food. However, if you take sildenafil with a high-fat meal, it will take longer for the medication to start to work.
If you are taking sildenafil to treat PAH, follow your doctor’s directions and the guidelines in this paragraph. You will probably take sildenafil three times a day with or without food. Take sildenafil at around the same times every day, and space your doses about 4 to 6 hours apart.
Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take sildenafil exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Shake the liquid well for 10 seconds before each use to mix the medication evenly. Use the oral syringe provided with your medication to measure and take your dose. Follow the manufacturer’s directions to use and clean the oral syringe. Do not mix the liquid with other medications or add anything to flavor the medication.
If you are taking sildenafil for erectile dysfunction, your doctor will probably start you on an average dose of sildenafil and increase or decrease your dose depending on your response to the medication. Tell your doctor if sildenafil is not working well or if you are experiencing side effects.
If you are taking sildenafil for PAH, you should know that sildenafil controls PAH but does not cure it. Continue to take sildenafil even if you feel well. Do not stop taking sildenafil without talking to your doctor.
Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient.
Other uses for this medicine
This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions should I follow?
Before taking sildenafil,
- tell your doctor and pharmacist if you are allergic to sildenafil, any other medications, or any of the ingredients in sildenafil products. Ask your pharmacist for a list of the ingredients.
- do not take sildenafil if you are taking or have recently taken riociguat (Adempas) or nitrates (medications for chest pain) such as isosorbide dinitrate (Isordil), isosorbide mononitrate (Monoket), and nitroglycerin (Minitran, Nitro-Dur, Nitromist, Nitrostat, others). Nitrates come as tablets, sublingual (under the tongue) tablets, sprays, patches, pastes, and ointments. Ask your doctor if you are not sure whether any of your medications contain nitrates.
- do not take street drugs containing nitrates such as amyl nitrate and butyl nitrate (‘poppers’) while taking sildenafil.
- tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention any of the following: alpha blockers such as alfuzosin (Uroxatral), doxazosin (Cardura), prazosin (Minipress), tamsulosin (Flomax, in Jalyn), and terazosin; amlodipine (Norvasc, in Amturnide, in Tekamlo); certain antifungals such as itraconazole (Onmel, Sporanox) and ketoconazole (Nizoral); anticoagulants (‘blood thinners’) such as warfarin (Coumadin, Jantoven); certain barbiturates such as butalbital (in Butapap, in Fioricet, in Fiorinal, others) and secobarbital (Seconal); beta blockers such as atenolol (Tenormin, in Tenoretic), labetalol (Trandate), metoprolol (Lopressor, Toprol XL, in Dutoprol), nadolol (Corgard, in Corzide), and propranolol (Hemangeol, Inderal LA, InnoPran); bosentan (Tracleer); cimetidine ; efavirenz (Sustiva, in Atripla); erythromycin (E.E.S., E-Mycin, Erythrocin); HIV protease inhibitors including amprenavir (Agenerase; no longer available in the U.S.), atazanavir (Reyataz, in Evotaz), darunavir (Prezista, in Prezcobix), fosamprenavir (Lexiva), indinavir (Crixivan), lopinavir (in Kaletra), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), saquinavir (Invirase), and tipranavir (Aptivus); nevirapine (Viramune); other medications or devices to treat erectile dysfunction; medications for high blood pressure; certain medications for seizures including carbamazepine (Carbatrol, Epitol, Tegretol, others), phenobarbital, and phenytoin (Dilantin, Phenytek); rifabutin (Mycobutin); and rifampin (Rifadin, Rimactane, in Rifamate, in Rifater). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with sildenafil, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
- tell your doctor what herbal products you are taking or plan to take, especially St. John’s wort.
- tell your doctor if you smoke, if you have ever had an erection that lasted for several hours, and if you have recently lost a large amount of body fluids (dehydration). This can happen if you are sick with fever, diarrhea, or vomiting; sweat a lot; or do not drink enough liquids. Also tell your doctor if you have or have ever had pulmonary veno-occlusive disease (PVOD; blockage of veins in the lungs); a stomach ulcer; heart, kidney, or liver disease; a heart attack; an irregular heartbeat; a stroke; chest pain; high or low blood pressure; high cholesterol; a bleeding disorder; blood circulation problems;blood cell problems such as sickle cell anemia (a disease of the red blood cells), multiple myeloma (cancer of the plasma cells), or leukemia (cancer of the white blood cells); conditions affecting the shape of the penis (e.g., angulation, cavernosal fibrosis, or Peyronie’s disease); or diabetes. Also tell your doctor if you or any of your family members have or have ever had an eye disease such as retinitis pigmentosa (an inherited eye condition that causes loss of vision) or if you have ever had sudden severe vision loss, especially if you were told that the vision loss was caused by a blockage of blood flow to the nerves that help you see.
- if you are a woman and you are taking sildenafil to treat PAH, tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking sildenafil, call your doctor.
- if you are having surgery, including dental surgery, tell your doctor or dentist that you are taking sildenafil.
- if you are taking sildenafil to treat erectile dysfunction, tell your doctor if you have ever been advised by a healthcare professional to avoid sexual activity for medical reasons or if you have ever experienced chest pain during sexual activity. Sexual activity may be a strain on your heart, especially if you have heart disease. If you experience chest pain, dizziness, or nausea during sexual activity, call your doctor immediately and avoid sexual activity until your doctor tells you otherwise.
- tell all your healthcare providers that you are taking sildenafil. If you ever need emergency medical treatment for a heart problem, the healthcare providers who treat you will need to know when you last took sildenafil.
What special dietary instructions should I follow?
Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medicine.
What should I do if I forget a dose?
If you are taking sildenafil for erectile dysfunction, you are unlikely to miss a dose since this medication is taken as needed, not on a regular dosing schedule.
If you are taking sildenafil for PAH, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What side effects can this medication cause?
Sildenafil may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- headache
- heartburn
- diarrhea
- flushing (feeling of warmth)
- nosebleeds
- difficulty falling asleep or staying asleep
- numbness, burning, or tingling in the arms, hands, feet, or legs
- muscle aches
- changes in color vision (seeing a blue tinge on objects or having difficulty telling the difference between blue and green)
- sensitivity to light
Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:
- sudden severe loss of vision (see below for more information)
- blurred vision
- sudden decrease or loss of hearing
- ringing in ears
- dizziness or lightheadedness
- fainting
- chest pain
- worsening shortness of breath
- erection that is painful or lasts longer than 4 hours
- itching or burning during urination
- rash
Some patients experienced a sudden loss of some or all of their vision after they took sildenafil or other medications that are similar to sildenafil. The vision loss was permanent in some cases. It is not known if the vision loss was caused by the medication. If you experience a sudden loss of vision while you are taking sildenafil, call your doctor immediately. Do not take any more doses of sildenafil or similar medications such as tadalafil (Cialis) or vardenafil (Levitra) until you talk to your doctor.
There have been reports of heart attack, stroke, irregular heartbeat, bleeding in the brain or lungs, high blood pressure, and sudden death in men who took sildenafil for erectile dysfunction. Most, but not all, of these people had heart problems before taking sildenafil. It is not known whether these events were caused by sildenafil, sexual activity, heart disease, or a combination of these and other causes.Talk to your doctor about the risks of taking sildenafil.
Some patients experienced a sudden decrease or loss of hearing after they took sildenafil or other medications that are similar to sildenafil. The hearing loss usually involved only one ear and did not always improve when the medication was stopped. It is not known if the hearing loss was caused by the medication. If you experience a sudden loss of hearing, sometimes with ringing in the ears or dizziness, while you are taking sildenafil, call your doctor immediately. If you are taking sildenafil (Viagra) for erectile dysfunction, do not take any more doses of sildenafil (Viagra) or similar medications such as tadalafil (Cialis) or vardenafil (Levitra) until you talk to your doctor. If you are taking sildenafil (Revatio) for PAH, do not stop taking your medication until you talk to your doctor.
Sildenafil may cause other side effects. Call your doctor if you have any unusual problems while you are taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).
What should I know about storage and disposal of this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store the tablets at room temperature and away from excess heat and moisture (not in the bathroom). Store the suspension at room temperature or in a refrigerator, but do not freeze it. Dispose of any unused suspension after 60 days.
It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org
Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.
In case of emergency/overdose
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.
What other information should I know?
Keep all appointments with your doctor.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
Brand names
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AHFS ® Patient Medication Information™. © Copyright, 2022. The American Society of Health-System Pharmacists ® , 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Cialis vs Viagra – An In-Depth Comparison
Viagra and Cialis are two popular erectile dysfunction treatments. We compare several factors including how fast they work, cost, duration, effectiveness and more. Find out which treatment is more effective for you!
Cialis (Tadalafil)
Viagra (Sildenafil)
What is Cialis?
Cialis is the brand name of the drug Tadalafil. Cialis Daily is a low dosage tablet which is taken once a day and allows you to achieve an erection at any time of the day or night. Cialis 36-hour is taken 15-20 minutes before sex and works for as long as 36 hours. Since November 2017, Cialis has been available as the generic medicine Tadalafil.
What is Viagra?
Viagra is the best-known treatment for erectile dysfunction and has been licensed for use for over 15 years. Millions of men across the world have found it to be a very effective treatment. Since 2013, Viagra has been available as a generic medicine called Sildenafil. As a consequence, the price for Sildenafil has fallen substantially.
How do Cialis and Viagra work?
Cialis, like Viagra (Sildenafil), is what is known as a PDE-5 inhibitor. When sexually stimulated, the PDE-5 class of drugs maintain a relaxed muscle state and increase the flow of blood to the penis to facilitate an erection. PDE-5 inhibitors do not increase interest or sexual desire and are only used to treat the physical problems associated with erectile dysfunction.
Does Cialis work more quickly than Viagra?
Although both have a fast onset of action, Cialis works faster than Viagra. While Viagra usually takes about 20-30 minutes, Cialis can work in 15-20 minutes. Cialis is also available as Cialis Daily, which is taken once a day, and will enable you to achieve an erection anytime throughout the day.
Does Cialis last longer than Viagra?
Cialis has a longer duration of action than Viagra, and can remain in the body for up to 36 hours. This has earned it the reputation of “The Weekend Pill”. This benefits you because you don’t need to pre-plan your dosage close to any expected sexual activity, but instead can utilise its effects up to 12, and sometimes 36 hours after taking it.
Is Viagra more effective than Cialis?
Both medications have a high success rate, helping the majority of men to regain control over their erection. In clinical trials for Viagra, Viagra 100mg was effective at treating 82 percent of patients; while in clinical trial data for Cialis, 81 percent of patients found that Cialis improved their erections. The clinical trial data indicates that both are effective and there is no significant difference between the two drugs.
Can Cialis or Viagra be taken with food?
Cialis can be taken with or without food without affecting how quickly it starts to work. Viagra on the other hand should be taken on an empty stomach otherwise it may take longer to take effect.
Winner: Cialis
Does Cialis have fewer side effects than Viagra?
As both drugs work in the same way, they share many of the same side effects. These include face flushing, headaches and indigestion. However, Viagra also has a few other effects that don’t seem to affect users of Cialis to the same extent, such as rash, visual disturbance and diarrhoea. Headaches also occur more commonly with Viagra, but may last longer with Cialis. If any of these affect you after taking a dose of Viagra, Cialis may be a better option.
Conclusion: Which is Better – Cialis vs Viagra?
Cialis is a more modern, effective treatment for erectile dysfunction. Cialis appears to offer advantages over Viagra for most desirable attributes for an erectile dysfunction medication, including duration of action, onset of action and less side effects. Both treatments are available as generic medicines at a similar price.
Winner: Cialis
Direct comparison of tadalafil with sildenafil for the treatment of erectile dysfunction: a systematic review and meta-analysis
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Abstract
Erectile dysfunction (ED) is a major care problem worldwide. Tadalafil and sildenafil are the two most common phosphodiesterase 5 inhibitors used to treat ED. This systematic review and meta-analysis were conducted to directly compare tadalafil with sildenafil for the treatment of ED.
Methods
We designed a strategy for searching the PubMed, Embase, EBSCO, Web of Science and Cochrane library databases; the reference lists of the retrieved studies were also investigated. A literature review was performed to identify all published randomized or non-randomized controlled trials that compared tadalafil with sildenafil for the treatment of ED and to assess the quality of the studies. Two investigators independently and blindly screened the studies for inclusion. The meta-analysis was performed using RevMan 5.0.
Results
A total of 16 trials that compared tadalafil with sildenafil for the treatment of ED were included in the meta-analysis. In the meta-analysis, tadalafil and sildenafil appeared to have similar efficacies and overall adverse event rates. However, compared with sildenafil, tadalafil significantly improved psychological outcomes. Furthermore, the patients and their partners preferred tadalafil over sildenafil, and no significant difference was found in the adherence and persistence rates between tadalafil and sildenafil. Additionally, the myalgia and back pain rates were higher and the flushing rate was lower with tadalafil than with sildenafil.
Conclusion
Tadalafil shares a similar efficacy and safety with sildenafil and significantly improves patients’ sexual confidence. Furthermore, patients and their partners prefer tadalafil to sildenafil. Hence, tadalafil may be a better choice for ED treatment.
Introduction
Erectile dysfunction (ED) is defined as the inability to achieve and maintain an erection sufficient to permit satisfactory sexual intercourse. ED is one of the most common sexual dysfunctions, and an estimated 5–20% of men are affected by moderate to severe ED around the world [1]. The prevalence of ED is approximately 15.77% in southern India, 15.0–49.5% in China, 56.1% in Iran and 58.9% in south-western Nigeria [2–5]. The estimated global prevalence has been increasing, and approximately 322 million men worldwide could be affected by ED by the year 2025 [6]. Although ED is a benign disorder, it can affect physical and psychosocial health and may have a significant impact on the quality of life of patients and their partners.
Currently, several treatment strategies are available for patients with ED, including non-invasive and invasive options. Oral phosphodiesterase type 5 inhibitors (PDE5-Is) are the first-line therapy for ED [7]. PDE5-Is are similar to cyclic guanosine monophosphate (cGMP) in structure; thus, PED5-Is can bind to PDE5 competitively and inhibit cGMP hydrolysis, leading to a penile erection [8]. Four PDE5-Is (sildenafil, tadalafil, vardenafil and avanafil) are currently approved by the US FDA and have comparable efficacy and side effect profiles [9]. Sildenafil and tadalafil are the two most common phosphodiesterase inhibitors (PDEIs) around the world. Sildenafil, the original PDEI, was introduced in 1998. Sildenafil has a quick onset of action of 30 min after the initial dose, a duration of action of 4–6 h and a maximum duration of 12 h [10]. Sildenafil is effective for the treatment of ED, although 20–50% of patients who respond to sildenafil discontinue its use [11]. Tadalafil is a selective, long-acting PDEI that was released in 2003. Tadalafil has an onset of 20 min and should be taken 30 min prior to intercourse; additionally, this drug has the longest duration of action in its class and a maximum duration of 72 h. A total of 52% of patients can have successful intercourse within 30 min of taking tadalafil [12]. Recently, several systematic reviews and meta-analyses have comparatively analysed the role of PDEIs, including sildenafil and tadalafil, in the treatment of ED. However, because most of these review articles were indirect comparative analyses, the differences between sildenafil and tadalafil remain unclear [13–15]. Hence, this meta-analysis was conducted to directly compare sildenafil with tadalafil for the treatment of ED and to provide guidance for the clinical treatment of ED.
Materials and methods
Search strategy
In January 2017, the PubMed, EBSCO, Web of Science, Cochrane library and Embase databases were searched for randomized or non-randomized controlled clinic trials of sildenafil and tadalafil. The search was performed by combining the term “erectile dysfunction or sexual dysfunction” with the following words describing the drug: tadalafil or Cialis and sildenafil or Viagra. We also searched for additional relevant studies by examining the reference lists of the selected papers and reviews. The search process was not limited by language, country or year of publication. The search strategy is presented in Fig. 1 .
Study selection
For the present systematic review, randomized or non-randomized controlled trials that met the following criteria were included: (a) the study included a comparison between sildenafil and tadalafil; (b) the study provided accurate data that applied to a meta-analysis, including the International Index of Erectile Function (IIEF)-EF domain, preference and treatment–emergent adverse events (TEAEs); and (c) the full text of the study could be acquired. When the same study was published in different journals or in different years, the most recent version was used for the meta-analysis. Abstracts, reviews and articles that did not contain accurate relevant data and a comparative analysis of sildenafil and tadalafil were excluded.
Quality assessment
Two independent reviewers evaluated all identified publications, and any disagreement between reviewers was resolved by a third reviewer. The methodological quality was assessed using the Jadad score, with a Jadad score ≥3 indicating a high-quality article [16].
Data extraction
Data extractions were performed by one reviewer and checked by a second reviewer. Information was extracted from the studies that met the above-mentioned inclusion criteria using a structured form. The first author, publication year, sample size, therapy that the patients received and assessment indices, including the IIEF, the men’s preference, the Self-Esteem and Relationship questionnaire (SEAR), total Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) scores and TEAEs, were collected for each study.
Statistical analysis
A meta-analysis of comparable data was performed using RevMan 5.0. Statistical heterogeneity between studies was assessed using the I 2 statistic. Pronounced heterogeneity was indicated by a P value ≤0.05 and an I 2 value ≥50%; in these cases, a randomized effects model was executed. A P value ≥0.05 and I 2 ≤ 50 indicated no obvious heterogeneity between the studies, and a fixed effects model was chosen for the meta-analysis. Continuous data are presented as weighted mean differences (WMDs), and odds ratios (ORs) were calculated for dichotomy [both with 95% confidence intervals (CIs)]. Egger’s test was performed to evaluate the risk of publication bias. Additionally, a sensitivity analysis was performed to assess the stability of the outcome when low-quality and highly heterogeneous trials were included in the analysis.
Results
Search results
A total of 1657 articles were identified through the electronic databases and the manual review of the reference lists of the included studies. Based on the search strategy, a total of 16 studies were included in the review [17–31]. A total of 5189 patients were recruited in the final meta-analysis, and the mean patient age ranged from 36.9 to 56.2 years. Seven articles were open-label, randomized, multicentre, controlled studies; nine of the studies had a crossover design; and the other studies were prospective and observational. All the studies compared sildenafil and tadalafil. The common instruments used to assess these two PDEIs (sildenafil and tadalafil) were the IIEF-EF, preference, TEAEs, adherence and persistence. The characteristics of the studies are listed in Table 1 .
Table 1
Characteristics of the included studies
| Author | Year | Number | Intervention | Control | Assessment | Jadad score |
|---|---|---|---|---|---|---|
| Bai et al. | 2016 | 383 | Tadalafil: 20 mg | Sildenafil: 100 mg | preference, TEAEs | 2 |
| Buvat et al. | 2013 | 770 | Tadalafil: 5 mg OaD, 10 mg PRN | Sildenafil: 50 mg PRN | IIEF score, TEAEs | 2 |
| Helen et al. | 2008 | 100 | Tadalafil: 20 mg | Sildenafil: 100 mg | Preference, IIEF-EF, TEAEs | 2 |
| Eardley et al. | 2005 | 291 | Tadalafil: 10 mg, 20 mg | Sildenafil: 25,50,100 mg | Preference, IIEF, TEAEs | 2 |
| Govier et al. | 2003 | 215 | Tadalafil: 20 mg | Sildenafil: 50 mg | Preference, TEAEs | 3 |
| Hatzimouratids et al. | 2014 | 770 | Tadalafil: 2.5, 5 mg OaD; 10, 20 mg PRN | Sildenafil: 25, 50, 100 mg PRN | IIEF | 3 |
| Rubio-Aurioles et al. | 2012 | 418 | Tadalafil: 5 mg OaD, 20 mg PRN | Sildenafil: 100 mg PRN | IIEF, TEAEs | 2 |
| Rodriguez Tolra et al. | 2006 | 90 | Tadalafil: 20 mg | Sildenafil: 50 mg, vardenafil: 20 mg | IIEF, preference, TEAEs | 2 |
| Von Keitz et al. | 2004 | 265 | Tadalafil: 20 mg | Sildenafil: 50 mg | preference, TEAEs | 3 |
| Li et al. | 2016 | 63 | tadalafil: 20 mg | sildenafil: 100 mg | preference, IIEF | 2 |
| Cairol et al. | 2014 | 104 | Tadalafil | Sildenafil, vardenafil, lodenafil | IIEF, persistence and adherence | 2 |
| Stroberg et al. | 2003 | 147 | Tadalafil: 20 mg | Sildenafil: 25, 50, 100 mg | preference, TEAEs | 2 |
| Ahn et al. | 2007 | 160 | Tadalafil: 20 mg | Sildenafil: 50, 100 mg | preference, TEAEs | 2 |
| El-Meliegy et al. | 2013 | 493 | Tadalafil | Sildenafil, vardenafil | persistence, adherence, IIEF, | 2 |
| Taylor et al. | 2009 | 409 | Tadalafil | Sildenafil, vardenafil | TEAEs | 2 |
| Rubio-Aurioles et al. | 2013 | 511 | Tadalafil | Sildenafil, vardenafil | persistence, adherence IIEF | 2 |
TEAE treatment–emergent adverse events, IIEF International Index of Erectile Function, OaD once a day, PRN on demand
Efficacy measures
A meta-analysis was conducted to examine the efficacy of sildenafil and tadalafil. No significant differences were found in the changes in the IIEF-EF between patients who used sildenafil and those who used tadalafil (random effects model: WMD: 0.03, 95% CI: −0.32 to 0.39, P = 0.85). The pooled mean effect size of the IIEF intercourse satisfaction result for tadalafil versus sildenafil was 0.45 (95% CI: −0.96 to 1.86, P = 0.53). Our analysis found heterogeneity among the trials, and a random effects model was adopted. Similarly, for IIEF overall satisfaction and IIEF sexual desire, the pooled mean effect sizes were 0.00, 95% CI: −0.03 to 0.03, P = 0.98 and 0.00, 95% CI: −0.02 to 0.02, P = 0.99, respectively; neither of these studies exhibited evidence of heterogeneity. Compared with sildenafil, tadalafil significantlly improved the SEAR Confidence (fixed effects model: WMD: 1.26, 95% CI: 1.04–1.45, P < 0.00001), SEAR Sexual Relationship (fixed effects model: WMD: 1.52, 95% CI: 1.32–1.72, P < 0.00001) and EDITS total scores (fixed effects model: WMD: 3.82, 95% CI: 3.63–4.01, P < 0.00001; Table 2 ; Fig. 2 ).
Table 2
| Index | Study | Heterogeneity test | Test for overall effect | Egger’s test | ||
|---|---|---|---|---|---|---|
| I 2 (%) | P | WMD (95% CI) | P | P | ||
| IIEF-EF | 3 | 96 | 0.03 [−0.32 to 0.39] | 0.85 | 0.783 | |
| IIEF intercourse satisfaction | 2 | 56 | 0.13 | 0.45 [−0.96 to 1.86] | 0.53 | – |
| IIEF overall satisfaction | 2 | 41 | 0.19 | 0.00 [−0.03 to 0.03] | 0.98 | – |
| IIEF sexual desire | 2 | 0 | 0.55 | 0.00 [−0.02 to 0.02] | 0.99 | – |
| SEAR confidence | 2 | 14 | 0.28 | 1.26 [1.04–1.45] | – | |
| SEAR sexual relationship | 2 | 43 | 0.19 | 1.52 [1.32–1.72] | – | |
| EDITS total | 2 | 0 | 0.93 | 3.82 [3.63–4.01] | – | |
IIEF International Index of Erectile Function, SEAR Self-Esteem and Relationship questionnaire, EDITS Erectile Dysfunction Inventory of Treatment Satisfaction
Forest plot of continuous variables: a IIEF-EF; b IIEF intercourse satisfaction; c IIEF overall satisfaction; d IIEF sexual desire; e SEAR confidence; f SEAR sexual relationship; g EDITS total
Preference, adherence and persistence
Table 3
| Index | Study | Heterogeneity test | Test for overall effect | Egger’s test | ||
|---|---|---|---|---|---|---|
| I 2 (%) | P | OR (95% CI) | P | P | ||
| Preference—man | 9 | 88 | 8.04 [4.99–12.96] | 0.129 | ||
| Preference—women | 2 | 48 | 0.17 | 14.50 [8.39–25.05] | – | |
| Adverse event | 5 | 0 | 0.55 | 1.09 [0.89–1.34] | 0.39 | 0.059 |
| Adverse event—headache | 12 | 37 | 0.09 | 0.97 [0.79–1.19] | 0.77 | 0.002 |
| Adverse event—myalgia | 4 | 0 | 0.51 | 4.89 [1.66–14.43] | 0.004 | – |
| Adverse event—back pain | 5 | 0 | 0.44 | 1.79 [1.06–3.02] | 0.03 | 0.229 |
| Adverse event—dyspepsia | 7 | 0 | 0.76 | 1.41 [0.98–2.03] | 0.06 | 0.106 |
| Adverse event—flushing | 10 | 0 | 0.87 | 0.39 [0.27–0.54] | 0.002 | |
| Adverse event—nasal congestion | 7 | 0 | 0.86 | 0.69 [0.45–1.06] | 0.09 | 0.014 |
| Adverse event—nasopharyngitis | 3 | 5 | 0.35 | 0.93 [0.52–1.67] | 0.8 | 0.042 |
| Adherence 3 months | 3 | 72 | 0.03 | 1.11 [0.52–2.35] | 0.79 | 0.889 |
| Adherence 6 months | 3 | 92 | 3.32 [0.74–14.93] | 0.12 | 0.622 | |
| Persistence 3 months | 3 | 66 | 0.05 | 1.29 [0.66–2.53] | 0.46 | 0.77 |
| Persistence 6 months | 3 | 27 | 0.25 | 1.33 [0.97–1.83] | 0.08 | 0.843 |
Forest plot of dichotomy: a preference—man; b preference—women; c adverse event; d adherence 3 months; e adherence 6 months
TEAEs
The most common TEAEs in patients treated with oral PDEIs included overall adverse events, headache, myalgia, back pain, dyspepsia, flushing, nasal congestion and nasopharyngitis. All the data were dichotomized, and ORs were calculated. For all studies, the random effects OR for the adverse events ratio of tadalafil versus sildenafil was 1.09 (95% CI: 0.89–1.34, P = 0.39), suggesting that the tadalafil and sildenafil groups shared a similar overall adverse events ratio. A total of 12 studies included headache data, and the pooled estimate of the OR was 0.97 (95% CI: 0.79–1.19, P = 0.77). The OR of myalgia for tadalafil compared with sildenafil based on the fixed effects model meta-analysis was larger (OR 4.89, 95% CI: 1.66–14.43, P = 0.004). Five articles contained back pain data, with no evidence of heterogeneity (I 2 = 0%, P = 0.44), and the pooled mean size for tadalafil versus sildenafil was 1.79 (95% CI: 1.06–3.02, P = 0.03). When comparing patients who suffered from flushing, significant differences were found between the tadalafil and sildenafil groups (fixed effects model: OR 0.39, 95% CI: 0.27–0.54, P < 0.00001). Other adverse events included dyspepsia, nasal congestion and nasopharyngitis, but no significant difference was found for these parameters between the tadalafil and sildenafil groups. The sensitivity analysis that excluded the above studies indicated that the pooled effect remained significantly different, and the direction of the forest plot did not change. Thus, the analysis results were stable (Table 3 ; Fig. 3 ).
Publication bias
Egger’s test was conducted to assess the presence of possible publication bias. No evidence of publication bias was found for the IIEF-EF, preference, overall adverse events, back pain, dyspepsia, nasopharyngitis, adherence and persistence (Egger’s test P ≥ 0.05). The Egger’s test results found publication bias for headache, flushing and nasal congestion (P ≤ 0.05). The other parameters were not evaluated using Egger’s test because only two studies included relevant data (Tables 2 , ,3; 3 ; Figs. 2 , ,3). 3 ). Study quality was evaluated with the Jadad scoring system, and the results are shown in Table 1 .
Discussion
According to a recent network meta-analysis published in 2015 that indirectly compared the efficacy and safety of PDEIs, sildenafil had the greatest efficacy but the highest rate of overall adverse events, whereas tadalafil had intermediate efficacy and the lowest overall rate of all adverse events [15]. However, our study, which differs from previous systematic reviews, is the first meta-analysis to directly compare the efficacy and safety of sildenafil and tadalafil. PDE5-Is selectively block the PDE5 enzyme, which catalyses the hydrolysis of cGMP to GMP and thus prolongs erectile function [32]. PDEIs are the most commonly used drugs to treat ED, and the effects of the PDEIs used to treat ED have been investigated. The IIEF is a widely used, validated and self-administered questionnaire that has demonstrated a high degree of sensitivity and specificity for the assessment of ED [33]. First, we used the IIEF to evaluate the overall efficacy of sildenafil and tadalafil. Previous studies reported that PDEIs were more effective than placebos for treating ED and were generally safe and well tolerated [13]. Interestingly, our efficacy analysis revealed that sildenafil and tadalafil had equivalent abilities to improve IIEF-EF scores. No significant between-group differences for tadalafil and sildenafil were evident for the IIEF sexual desire, IIEF intercourse satisfaction and IIEF overall satisfaction domains. This finding is somewhat unexpected and may result from differences in the distribution of efficacy profiles within the different treatment strata assessed. However, a high level of significant between-trial heterogeneity was evident across the articles included in this meta-analysis, and the time or dose of administration of the PDEIs was diverse. The sensitivity analysis based on various exclusion criteria did not alter the forest plot and pooled effect, which strengthened our result.
ED involves both physiological and psychological factors, and increasing importance has recently been attached to the psychological aspects of ED diagnosis and management [34, 35]. PDEIs can improve a patient ’ s sexual confidence both directly, via improved EF, and indirectly, via improved spontaneity and diminished time concerns. Tadalafil significantly improves EF among psychogenic ED patients [36, 37]. Furthermore, pooled evidence suggests that tadalafil improves psychological outcomes, including the SEAR Confidence and Sexual Relationship scores and the total EDITS scores, to a greater degree than sildenafil. The SEAR is a subject-reported measure of psychosocial outcomes in men with ED, whereas the EDITS is a reliable and validated questionnaire used to assess patient satisfaction with ED treatment [38, 39]. The study by Eusebio Rubio-Aurioles revealed that the time concerns domain score was significantly lower for tadalafil once a day (OaD) compared with sildenafil PRN (on demand) treatment (P < 0.001) [23]. Thus, tadalafil improves sexual confidence more efficiently than sildenafil.
The adverse event rate for PDE5-Is is greater than the rate for placebos, but PDE5-Is are generally well tolerated for the treatment of ED. The most common adverse drug reactions include headache, flushing, nasal congestion, nasopharyngitis and dyspepsia [40], which are reflections of the vasodilatory effects on the capillary smooth muscle in other parts of the body. A trade-off network meta-analysis published by Yuan J suggested that PDE5-Is were generally safe and well tolerated and found no major difference in the safety profiles [13]. A later systematic review revealed that sildenafil had the highest rate of overall adverse events and that tadalafil had the lowest overall rate of all adverse events [15]. However, our meta-analysis suggests that the overall adverse event rate of tadalafil is equal to that of sildenafil, although the specific adverse events differ. For instance, there is no significant difference in the incidence of headache, dyspepsia, nasal congestion or nasopharyngitis between tadalafil and sildenafil, but tadalafil is associated with a higher incidence of myalgia and back pain and a lower occurrence of flushing than sildenafil. Furthermore, we found that the adherence and persistence rates of tadalafil were equal to those of sildenafil, which may be due to the medications’ similar efficacy, safety and tolerability properties.
In this study, we found that the majority of the patients and their partners preferred tadalafil over sildenafil. Currently, there are several effective and safe oral PDE5-Is for the treatment of ED, and various factors that are important to both the patient and his partner, such as biological, social, psychological and/or cultural factors, will influence the treatment choices [29]. Current ED guidelines also emphasize that the assessment of ED treatment must consider the effects on patient and partner satisfaction, which include psychosocial outcomes as well as efficacy and safety [1]. Therefore, this analysis evaluated the psychosocial outcomes and drug attributes of tadalafil versus sildenafil and found that tadalafil could improve psychosocial outcomes, including the SEAR Confidence and Sexual Relationship scores and the total EDITS scores, more than sildenafil. A previous study suggested that time concerns appeared to play a role in patient decisions regarding the ED treatment type, and the study by Eusebio Rubio-Aurioles reported that significant improvements in the PAIRS time concerns were observed after baseline. The improvement in the tadalafil group was superior to that of the sildenafil group, indicating that men who took tadalafil felt less time pressure and a reduced sense of urgency and had to do less planning before and during sexual encounters compared with those taking sildenafil [23]. Additionally, the mean half-life of sildenafil is approximately 4 h, with demonstrated improvement in EF for up to 8–12 h post-dose; conversely, the mean half-life of tadalafil is 17.5 h, with demonstrated improvement in EF for up to 36 h post-dose. The different pharmacokinetic profiles of tadalafil and sildenafil profiles grant patients more freedom to perform sexual intercourse with less need to plan ahead [41].
We must acknowledge the limitations of this meta-analysis. First, the studies included in the present meta-analysis were randomized or non-randomized controlled studies, and the blinding methods of these studies were not described in detail. We noted that the studies had flaws in quality, primarily in terms of the study design, patient selection, blinding and outcome data; thus, the results of this meta-analysis should be interpreted with caution. However, the results were strengthened by the fact that most of the included studies were randomized, multicentre trials. Second, high heterogeneity of IIEF-EF, IIEF intercourse satisfaction, men’s preference, adherence and persistence was found; this could be explained by the inclusion of studies with a low sample size and the various timing or doses of the PDEIs. A sensitivity analysis based on various exclusion criteria did not alter the forest plot and pooled effect, which strengthened our results. Third, when examining the risk of bias table across studies, we found publication bias for headache, flushing and nasal congestion, which limited the stated conclusions. Hence, a large-scale, high-quality, randomized, double-blind trial should be included in the meta-analysis to provide good evidence for the selection of specific PDEIs for the treatment of ED in the future. A comprehensive assessment of biases, study quality and heterogeneity should be a routine component of systematic reviews. Although the methods may be hampered by issues such as a low number of studies, large effect sizes and the design of the included studies, comprehensive assessments allow the reader to be more confident that the evidence presented is robust and that simple causes of confounding have been considered and explored. Without such an assessment, the conclusions of a systematic review may be weak and could lead to the application of inappropriate practices in healthcare settings.
Conclusion
Tadalafil and sildenafil have been shown to exhibit comparable efficacy, safety and satisfaction for the treatment of ED, and tadalafil dramatically improved the psychological outcomes. The adherence and persistence rates for tadalafil and sildenafil were equal. Furthermore, both men and women preferred tadalafil to sildenafil for the treatment of ED. Thus, tadalafil may be a better choice for ED treatment. The findings of this meta-analysis will provide important evidence for the selection of PDEIs for the clinical treatment of ED.
Cialis vs. Viagra: What’s the Difference?
Used by millions of men in the United States alone, PDE5 inhibitors such as tadalafil (the active ingredient in Cialis®) and sildenafil (the active ingredient in Viagra®) are two of the most widely used drugs for treating erectile dysfunction (ED), and for good reason.
Cialis and Viagra both work in very similar ways and have similar effects on your erections and sexual performance. But when it comes to effectiveness, convenience, safety and affordability between Cialis and Viagra, which contender wins out?
The truth is that although Cialis and Viagra are similar, there are a few key differences between these two medications that may make one medication a better choice for you than the other.
Below, we’ve compared Cialis and Viagra on several criteria, from their effectiveness as options for treating ED to their duration of action, ability to be taken with food, potential side effects and more.
We’ve also shared a few things that you should know about taking Cialis or Viagra before using either medication to treat ED, including potential drug interactions.
What is Viagra?
Viagra is a brand name medication for treating erectile dysfunction, or ED. It contains the active ingredient sildenafil and was developed by Pfizer throughout the 1980s and early 90s, originally as a treatment for angina (a type of chest pain caused by certain heart conditions).
During testing for sildenafil, researchers discovered that many of the participants in their clinical trials reported erections as a side effect.
Viagra was approved by the FDA in 1998, making it the first prescription medication for treating erectile dysfunction. It’s now widely sold as brand name Viagra and as a generic medication as sildenafil.
Both Viagra and generic sildenafil are available as oral medications, meaning tablets you take in advance of sex. It takes about 30 to 60 minutes for a normal dose of Viagra to start working and provide relief from erectile dysfunction.
What is Cialis?
Cialis is also a brand name, prescription medication that’s approved by the FDA for treating ED, or erectile dysfunction. It contains the active ingredient tadalafil and was originally developed by Lilly ICOS, a company now owned by Eli Lilly and Company.
Tadalafil, the active ingredient in Cialis, gained approval from the FDA in 2003. Today, tadalafil is available in brand name form as Cialis and as a generic medication. Like sildenafil, it comes as an oral tablet for use before sex.
How Cialis and Viagra Work
To understand how Cialis and Viagra work as ED medications, it’s important to quickly go over the basics of how you get an erection in the first place.
Erections start with stimulation, either sensory (when someone touches you, or you hear or see something sexually arousing) or mental (when you visualize a sexual moment). When you start to become sexually aroused, your nervous system stimulates your penis.
As nerve impulses from your brain and the nerves around your penis start to have an effect, the blood vessels that supply your penis dilate, allowing more blood to flow into your penis.
This blood flows into a pair of sponge-like, elongated areas of erectile tissue called the corpora cavernosa, which run along the length of your penis. As blood flows in, this tissue expands and becomes firmer, creating a penile erection.
As your penis increases in length and firmness, a fibrous membrane called the tunica albuginea contracts, preventing blood from escaping the tissue while you have sex.
After you reach orgasm and ejaculate, the same process occurs, but in reverse, with the fibrous tissue relaxing and blood exiting your penis via outward-flowing blood vessels.
So, how do ED medications like Cialis, Viagra and others fit into this process, and how can they make it easier to get an erection?
Cialis and Viagra, as well as their generic equivalents, belong to a class of drugs referred to as PDE5 inhibitors. These medications work by inhibiting the actions of an internal enzyme called phosphodiesterase type 5 (or PDE5, for short).
PDE5 is present inside the smooth muscle cells of certain blood vessels, including the vessels that supply blood to your penis. Through a complex mechanism, PDE5 works to regulate the flow of blood to your penis and other areas of your body with blood vessels containing PDE5.
By inhibiting the actions of PDE5, medications like Cialis and Viagra increase the total amount of blood that can flow to your penis when you’re sexually aroused.
This increase in blood flow can make it easier for you to get an erection when you feel ready to have sex and maintain it during sexual intercourse.
Now, it’s important to understand that the effects of Cialis, Viagra and similar medications solely target your vascular system — that is, the vessels that transport blood throughout your body and to your penis.
They aren’t “sex pills,” and they won’t make you feel sexually aroused on their own, nor will they have an effect on the hormones that give you sexual desire.
However, because medications like Cialis and Viagra can make it easier to get and maintain an erection (and in turn, improve your sexual performance), they can make it easier to get and stay hard when you’re already sexually aroused.
Because both drugs work by affecting the blood vessels that supply your penis, it’s important to be careful before using them if you have a cardiovascular issue, such as high blood pressure, a history of heart disease or if you’ve previously had a heart attack.
We’ve discussed these issues — as well as the steps that you can take to use Cialis or Viagra as safely as possible — further down the page.
genuine Viagra® makes it possible
Does Cialis or Viagra Last Longer?
Although Cialis and Viagra work very similarly to improve blood flow to your penis and treat ED, there’s a huge difference in terms of the amount of time that each medication remains active in your body.
Cialis is a long-lasting erectile dysfunction medication. In fact, it’s sometimes referred to as the “weekend pill” for treating ED because it can last for so long.
On average, a normal dose of Cialis or generic tadalafil will offer relief from erectile dysfunction for approximately 36 hours.
This long-lasting effect makes Cialis or generic tadalafil an excellent choice if you’re affected by erectile dysfunction, but don’t know exactly what time of day you’re going to have sexual activity with your partner.
Whether you’re going away for a weekend or just want to be prepared for a more spontaneous sexual encounter without needing to plan out taking oral drugs for ED ahead of time, a dose of Cialis is usually more than enough.
Viagra, on the other hand, is a shorter-acting medication for erectile dysfunction. On average, a normal dose of Viagra or generic sildenafil will provide relief from erectile dysfunction for around four hours.
This means that Viagra can be a great choice if you need short-term relief from ED, such as for a single night. For example, if you need a sexual confidence boost after a date, taking a Viagra or generic sildenafil tablet can let you focus on enjoying yourself without worrying about ED.
People’s needs from ED medication can differ dramatically, so it’s best to talk to your healthcare provider before deciding that a specific medication is going to be best for you based on the time it’s active within your body.
It’s also important to keep in mind that Cialis and Viagra don’t always last for precisely 36 or four hours per dose. You may notice the effects of either medication fading sooner or later based on factors such as your body weight, eating habits and certain medical conditions.
However, in general, Cialis is longer lasting and a better choice for weekends that could involve multiple sexual encounters, whereas Viagra is usually a better choice if you need to treat sexual dysfunction like ED for a single evening.
Which Medication Works Faster?
Cialis and Viagra are both fast-acting medications that should produce noticeable improvements in your erections and sexual function within one hour.
On average, it takes around 30 minutes for Cialis to start working. In some cases, you may not notice the full effects of Cialis on your erections and general sexual peformance for one to two hours after taking the medication.
Similarly, Viagra typically starts to work within 30 minutes, although it may take about one hour for the effects of the medication to become fully apparent.
Regardless of whether you use Cialis or Viagra, a few simple techniques can help you to make sure that your medication works in time for you to have sex:
Aim to take your medication about an hour before sex. This way, the medication will be completely active (or close to completely active) by the time you and your partner begin sexual activity.
Take note of how long it takes before you “feel” the effects of your medication. You may notice that it takes a certain amount of time before you can notice improvements in your erections. This knowledge can help you to “tailor” your future use of ED medication.
Avoid eating too much food before using ED medication. Some ED medications, such as Viagra, may take longer to work if taken with a large meal. We’ve discussed the effects of high-fat meals on ED medication in more detail below.
In general, both medications take a similar amount of time to start working and should be taken 30 to 60 minutes before sex for optimal results.
Which Medication is More Effective: Cialis or Viagra?
Cialis and Viagra are both highly effective as treatments for ED. Both medications have passed through comprehensive, large-scale clinical trials as part of the FDA approval process, with the research showing that both medications work well at producing improved erections.
For example, in an article published in the journal Clinical Interventions in Aging, experts looked at the existing efficacy data for tadalafil (the active ingredient in Cialis) to judge its effectiveness as a treatment for erectile dysfunction.
They found that 88 percent of men with erectile dysfunction reported successful erections after taking Cialis, versus approximately 64 percent of men who used a non-therapeutic placebo.
They also found that the men who used Cialis reported higher levels of sexual satisfaction, as well as more successful attempts at sexual intercourse.
A meta-analysis of clinical trial reports for sildenafil (the active ingredient in Viagra) also found that it was an effective drug for improving erectile function in men with ED.
The meta-analysis, which was published in the journal BMC Urology, noted that 82 percent of men with erectile dysfunction reported improved erections after using sildenafil at a dosage of 100mg prior to sex.
The men who used sildenafil were also more able to successfully have penetrative sex with their partners, suggesting that sildenafil produced improvements in sexual satisfaction.
When it comes to medication, It’s easy to get obsessed with numbers and assume that because one medication shows an improvement in a slightly larger number of men, it must be the best of the two options.
However, the reality is that Cialis and Viagra are both extremely effective treatments for erectile dysfunction, and that the tiny differences in effectiveness shown in some studies are just that — tiny differences.
Put simply, if you have erectile dysfunction and want a reliable drug that can enhance blood flow and give you reliable, prolonged erections, Cialis and Viagra are both good options.
