# Avanafil (Stendra): the fourth ED pill, and how it compares

> Avanafil, sold as Stendra, is the fourth FDA-approved PDE5 inhibitor pill for erectile dysfunction, approved in 2012. It works the same way as sildenafil and tadalafil and still needs sexual stimulation. What sets it apart on its label is a fast rise in blood levels and a 12-hour nitrate window, and its label says it may be taken with or without food.

_Last updated: 2026-10-17_

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Status: FDA-approved prescription medicine for ED. Source: Stendra prescribing information (Metuchen Pharmaceuticals), DailyMed, checked 2026-10-17.

**In short:** avanafil is the least familiar of the four PDE5 inhibitor pills approved in the US for erectile dysfunction. The FDA approved it as Stendra in April 2012 ([Drugs@FDA, NDA 202276](https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=202276)), and its current DailyMed label lists Metuchen Pharmaceuticals as the labeler ([Stendra label, DailyMed](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)). It works through the same enzyme as Viagra and Cialis. The differences are in timing, food, a few interaction rules and how it ranks in pooled trial data, and this page takes each one from the label or a published study. **Evidence level:** an approved drug backed by four placebo-controlled trials; comparisons with the other pills come mostly from network meta-analyses, not head-to-head trials.

| Label feature                                                        | Avanafil (Stendra)                                                                 | Sildenafil (Viagra)                                        | Tadalafil (Cialis)                    |
| -------------------------------------------------------------------- | ---------------------------------------------------------------------------------- | ---------------------------------------------------------- | ------------------------------------- |
| First US approval                                                    | 2012                                                                               | 1998                                                       | 2003                                  |
| Time to peak blood level (fasted)                                    | Median 30 to 45 minutes                                                            | 30 to 120 minutes, median 60 minutes                       | 30 minutes to 6 hours, median 2 hours |
| Half-life                                                            | About 5 hours                                                                      | About 4 hours                                              | 17.5 hours (mean)                     |
| High-fat meal                                                        | Peak about 1.12 to 1.25 hours later and 39% lower; label says with or without food | Peak about 60 minutes later and 29% lower                  | Label says without regard to food     |
| Earliest nitrate use after a dose, in an emergency, under monitoring | At least 12 hours                                                                  | Label says it is unknown when nitrates can be given safely | At least 48 hours                     |
| Retina enzyme (PDE6) selectivity, lab                                | More than 100-fold                                                                 | About 10-fold                                              | 700-fold                              |
| Never combine with                                                   | Nitrates, riociguat, vericiguat                                                    | Nitrates, riociguat                                        | Nitrates, riociguat                   |

Figures come from the FDA prescribing information for [Stendra](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6), [Viagra](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0b0be196-0c62-461c-94f4-9a35339b4501) and [Cialis](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=bcd8f8ab-81a2-4891-83db-24a0b0e25895). Each label reports its own studies, so the rows sit side by side but are not a head-to-head test. Doses and timing for any of these pills are set by the label and the prescriber, so they are left out here.

## What is avanafil?

Avanafil is a prescription phosphodiesterase 5 (PDE5) inhibitor, and the Stendra label says it is "indicated for the treatment of erectile dysfunction in adult males" ([Stendra label, section 1](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)). It is a pale yellow tablet, and the label lists its initial US approval as 2012. The label also says it is not indicated for women or for anyone under 18. Stendra is the brand name; avanafil is the active ingredient, the same way sildenafil sits inside Viagra.

## How does avanafil work?

Avanafil blocks PDE5, the enzyme that breaks down cGMP, the chemical messenger that relaxes the smooth muscle in the penis so blood can flow in during arousal. The label explains that arousal releases nitric oxide, which raises cGMP, and that avanafil "has no direct relaxant effect" on the tissue itself; it only keeps that signal going longer, so "the inhibition of PDE5 has no effect in the absence of sexual stimulation" ([Stendra label, section 12.1](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)). That is the same mechanism as sildenafil and tadalafil, which our explainer on [how ED medications work](/how-ed-medications-work/) walks through step by step.

## How is avanafil different from sildenafil and tadalafil?

On paper, avanafil sits closest to sildenafil: both are short-acting pills with half-lives of roughly 4 to 5 hours, while tadalafil's half-life is 17.5 hours ([Stendra label](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6); [Viagra label](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0b0be196-0c62-461c-94f4-9a35339b4501); [Cialis label](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=bcd8f8ab-81a2-4891-83db-24a0b0e25895)). Where avanafil stands out is speed of absorption: its label gives a median time to peak blood level of 30 to 45 minutes when fasted, against a median of 60 minutes for sildenafil and 2 hours for tadalafil. In lab tests, avanafil is more than 100 times more potent at PDE5 than at PDE6, the related enzyme in the retina, while sildenafil is only about 10 times more potent; the Viagra label ties its color-tinged vision effect to that lower selectivity. Lab selectivity is a hint, not proof of fewer side effects, and each label reports its own studies. For the two older pills side by side, see [tadalafil vs sildenafil](/tadalafil-vs-sildenafil/).

## Avanafil vs Viagra: is it the same drug?

No. Avanafil and Viagra (sildenafil) are different molecules in the same drug class, made by different companies and approved under separate FDA applications. They share the same mechanism, the same need for arousal and the same ban on nitrates ([Stendra label](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6); [Viagra label](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0b0be196-0c62-461c-94f4-9a35339b4501)). They differ in how quickly blood levels rise, how much a fatty meal slows them, how long the label says to wait before emergency nitrates, and how they rank in pooled trial data, covered below. Our explainer on [what sildenafil is](/what-is-sildenafil/) covers Viagra's own label in full.

## What did the trials measure about how fast avanafil works?

One trial, Study 4 on the label, was built to test speed. It enrolled 440 men with ED, about 41% of them with severe ED and 16% with diabetes, who were encouraged to attempt intercourse about 15 minutes after taking avanafil or placebo and timed the onset with a stopwatch ([Stendra label, section 14](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)). Its main measure was the share of attempts with an erection firm enough for penetration at about 15 minutes that went on to successful intercourse. The mean was 25.9% and 29.1% in the two avanafil groups against 14.9% on placebo, a statistically significant difference, though the median on placebo was zero ([Hellstrom et al., Journal of Urology, 2015](https://pubmed.ncbi.nlm.nih.gov/25591992/)).

The published paper also reported a significant difference from placebo as early as 10 to 12 minutes after dosing. Two things keep this in proportion. Most attempts at the 15-minute mark did not succeed even on avanafil, and several of the authors worked for the companies behind the drug. The prescriber sets the timing for each man.

## How well did avanafil work in its main trials?

In the general ED trial (Study 1, 646 men, 3 months), every avanafil dose beat placebo on all three main measures. The share of attempts ending in successful intercourse rose to 41% to 57% on avanafil, depending on dose, against 27% on placebo ([Stendra label, section 14](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)). Gains were smaller in harder-to-treat groups. In men with diabetes (Study 2, 390 men), successful attempts reached 34% to 40% against 20.5% on placebo. In men after nerve-sparing prostate removal (Study 3, 286 men), they reached 23% to 26% against 9% on placebo. Those percentages are trial averages across many attempts, not a forecast for one man.

## Avanafil vs sildenafil and tadalafil: which works better?

The pooled evidence generally ranks avanafil below sildenafil and tadalafil for effect, while noting that most comparisons are indirect. A 2015 network meta-analysis of 82 trials (47,626 men) found that avanafil at a usual starting dose had side-effect rates similar to sildenafil but "a markedly lower global efficacy" ([Chen et al., European Urology, 2015](https://pubmed.ncbi.nlm.nih.gov/25817916/)). A 2021 analysis of 179 trials (50,620 men) called avanafil one of the "less effective interventions" ([Madeira et al., World Journal of Urology, 2021](https://pubmed.ncbi.nlm.nih.gov/32388784/)). A 2026 dose-specific network meta-analysis of 83 trials put sildenafil first on the odds of reaching satisfactory erectile function, reported the lowest odds for the lower avanafil dose among the doses listed in its abstract, and ranked avanafil's odds of treatment-related side effects second only to vardenafil's ([Salonia et al., Journal of Sexual Medicine, 2026](https://pubmed.ncbi.nlm.nih.gov/42296271/)). Two of that paper's authors were employed by the drug company Viatris, and network rankings rest on indirect comparisons, so these are group-level rankings, not a verdict for any one man.

## Does food affect avanafil?

A fatty meal slows avanafil down but barely changes how much of it the body absorbs. With a high-fat meal, the label reports peak blood levels arriving about 1.12 to 1.25 hours later and 39% lower, with total exposure down only about 3.8%, and it calls those changes "of minimal clinical significance," so avanafil "may be taken with or without food" ([Stendra label, sections 2.2 and 12.3](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)). For comparison, a high-fat meal delays sildenafil's peak by about 60 minutes and lowers it by 29% ([Viagra label, section 12.3](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0b0be196-0c62-461c-94f4-9a35339b4501)), and Cialis "may be taken without regard to food" ([Cialis label, section 2](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=bcd8f8ab-81a2-4891-83db-24a0b0e25895)). In the trials, food and alcohol were not restricted. Grapefruit juice is a separate issue, covered under interactions.

## What are the side effects of avanafil?

The side effects the label lists most often are headache, flushing, a stuffy nose, sore throat or cold symptoms and back pain. In three placebo-controlled trials, headache was reported by 5.1% to 10.5% of men on avanafil depending on dose, against 1.7% on placebo; flushing by 3.2% to 4.3%, against none on placebo; and nasal congestion by 1.8% to 2.9% ([Stendra label, section 6.1](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)). Between 1.4% and 2.0% of men on avanafil stopped because of side effects, depending on dose, against 1.7% on placebo. Across all trials, one man reported a change in color vision. The label warns that side-effect rates from different drugs' trials cannot be compared directly. Our guide to [ED medication side effects](/ed-medication-side-effects/) covers the class as a whole.

Rarer warnings match the rest of the class: sudden vision loss in one or both eyes (a possible sign of the optic nerve condition NAION), sudden hearing loss, and erections lasting more than 4 hours. The label says to stop avanafil and seek care for the first two, and to get emergency help for the third ([Stendra label, sections 5.3 to 5.5](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)).

## What are avanafil's interactions?

The interaction rules fall into two groups: medicines that drop blood pressure further, and medicines that raise avanafil levels in the blood. Avanafil must never be taken with nitrates "in any form," or with the heart and lung drugs riociguat or vericiguat ([Stendra label, section 4](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)). Alpha-blockers such as doxazosin and tamsulosin, other blood pressure medicines and substantial drinking, for which the label's example is more than 3 units of alcohol, can add to its blood-pressure-lowering effect.

Avanafil is cleared mainly by the liver enzyme CYP3A4, so drugs that block that enzyme raise its levels. Ketoconazole raised avanafil exposure about 13-fold, and ritonavir also about 13-fold, so the label says not to use avanafil at all with strong CYP3A4 blockers such as ketoconazole, itraconazole, clarithromycin and several HIV protease inhibitors ([Stendra label, section 7.2](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)). With moderate blockers, such as erythromycin, diltiazem, verapamil and fluconazole, the label sets a lower limit, and it says grapefruit juice is likely to raise exposure too. The label also says combining avanafil with other ED treatments has not been studied and is not recommended. For how these rules look on the sildenafil side, see [sildenafil drug interactions](/sildenafil-drug-interactions/).

  Do not take avanafil with any nitrate medicine, including nitroglycerin, or
  with riociguat or vericiguat. If chest pain starts after taking avanafil, get
  emergency care and tell the team when you took it. Get emergency help for an
  erection lasting more than 4 hours, and stop avanafil and seek care for sudden
  loss of vision or hearing.

## Who should not take avanafil, or should be extra careful?

Some men were left out of avanafil's trials, so the label does not recommend it for them until more is known. That group includes men who in the last 6 months had a heart attack, stroke, life-threatening heart rhythm problem or a procedure to reopen heart arteries, men with resting blood pressure below 90/50 or above 170/100, and men with unstable angina, angina during intercourse or heart failure of New York Heart Association class 2 or higher ([Stendra label, section 5.1](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)). The label says not to use it with severe kidney disease or dialysis or with severe liver disease, and it does not recommend it for men with inherited retinal disease such as retinitis pigmentosa. It asks for caution with a curved or scarred penis, including Peyronie's disease, and with conditions that raise the risk of a prolonged erection, such as sickle cell anemia.

## Is there a generic avanafil, and what does it cost?

Yes. The FDA approved a generic avanafil application from Hetero Labs in June 2024, with an "AB" rating, meaning the FDA rates it therapeutically equivalent to Stendra ([Drugs@FDA, ANDA 209266](https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=209266)), and a generic avanafil tablet label from Camber Pharmaceuticals is listed on DailyMed ([avanafil tablets, DailyMed](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1d04e17d-7399-430a-a8bb-fa1912b155e9)). An approved generic is a different thing from a compounded or "research" product, which is not FDA-approved. Prices depend on the strength, the quantity, the pharmacy and any discount program, so it is worth comparing current prices for the exact prescription. Our breakdown of [what online ED treatment costs](/online-ed-treatment-cost/) explains how visit fees and pharmacy prices add up.

## When should you talk to a clinician about avanafil?

Before taking it, because avanafil is a prescription medicine and the label says ED should first be checked for underlying causes ([Stendra label, section 5](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)). The American Urological Association says men with ED should be told about FDA-approved oral PDE5 inhibitors, "including discussion of benefits and risks/burdens, unless contraindicated," and that ED "is a risk marker for underlying cardiovascular disease" worth checking ([AUA Erectile Dysfunction guideline]()). Bring a full list of medicines, including antifungals, antibiotics, HIV drugs, blood pressure and prostate medicines, and mention any heart, eye, kidney or liver history. A man who wants a short-acting pill with a fast rise in blood levels may have reasons to ask about avanafil; a man who wants the strongest pooled track record or a longer window may be pointed elsewhere. Which pill fits, and how to take it, is a decision for you and the prescriber.

## Sources

1. [Stendra (avanafil) tablets, prescribing information and patient information, Metuchen Pharmaceuticals, DailyMed (label version July 2024)](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fa7d93e3-b69b-4e02-8146-89760cd8e9d6)
2. [Viagra (sildenafil citrate) tablets, prescribing information, Pfizer, DailyMed](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0b0be196-0c62-461c-94f4-9a35339b4501)
3. [Cialis (tadalafil) tablets, prescribing information, Eli Lilly, DailyMed](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=bcd8f8ab-81a2-4891-83db-24a0b0e25895)
4. [Drugs@FDA: NDA 202276, Stendra, US Food and Drug Administration](https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=202276)
5. [Drugs@FDA: ANDA 209266, avanafil, US Food and Drug Administration](https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=209266)
6. [Avanafil tablets, Camber Pharmaceuticals, DailyMed](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1d04e17d-7399-430a-a8bb-fa1912b155e9)
7. [Hellstrom WJ et al. Efficacy of avanafil 15 minutes after dosing in men with erectile dysfunction: a randomized, double-blind, placebo controlled study. Journal of Urology, 2015](https://pubmed.ncbi.nlm.nih.gov/25591992/)
8. [Chen L et al. Phosphodiesterase 5 inhibitors for the treatment of erectile dysfunction: a trade-off network meta-analysis. European Urology, 2015](https://pubmed.ncbi.nlm.nih.gov/25817916/)
9. [Madeira CR et al. Efficacy and safety of oral phosphodiesterase 5 inhibitors for erectile dysfunction: a network meta-analysis and multicriteria decision analysis. World Journal of Urology, 2021](https://pubmed.ncbi.nlm.nih.gov/32388784/)
10. [Salonia A et al. A comparative evaluation of on-demand phosphodiesterase-5 inhibitor efficacy in erectile dysfunction treatment: a systematic review and network meta-analysis. Journal of Sexual Medicine, 2026](https://pubmed.ncbi.nlm.nih.gov/42296271/)
11. [Erectile Dysfunction: AUA Guideline, American Urological Association]()

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