How it works
Avanafil is a selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5), the enzyme that degrades cyclic guanosine monophosphate (cGMP) in the smooth muscle cells of the corpus cavernosum. During sexual stimulation, local release of nitric oxide (NO) activates guanylate cyclase, raising cGMP levels and producing smooth muscle relaxation that allows blood to enter the erectile tissue. By preventing cGMP breakdown, avanafil amplifies this NO–cGMP signal. It has no direct relaxant effect on the corpus cavernosum and exerts no action in the absence of sexual stimulation. In vitro, avanafil is more than 100-fold selective for PDE5 over PDE6 (found in the retina) and more than 1,000-fold selective over PDE4, PDE8 and PDE10. (DailyMed avanafil label)How to use
Two things decide whether a dose is safe and useful: the timing, and what else is in your system.Take 100 mg about 15–30 minutes before sex
The usual starting dose is 100 mg. Depending on response and tolerability, the prescriber may choose 50 mg or 200 mg. Take no more than once per day, and remember that sexual stimulation is required.
Avoid contraindicated combinations
Never take avanafil with nitrates, nitric-oxide donors, riociguat, or another erectile-dysfunction medicine. Strong CYP3A4 inhibitors are also contraindicated; some moderate inhibitors require no more than 100 mg every 48 hours.
Dose schedule
Before each dose, check for any new heart, blood-pressure, prostate, antifungal, antibiotic, or HIV medicines. Food can delay onset, so use the timing agreed with your prescriber. After several correctly timed attempts, review efficacy and effects with the prescriber — do not repeat the dose on the same day or move to 200 mg without approval.Clinical evidence
Avanafil was evaluated in the REVIVE trial (NCT00790751), a randomised, double-blind, placebo-controlled phase 3 study in 646 men with erectile dysfunction of at least six months’ duration (of whom 72% had tried another ED treatment). Patients received placebo or avanafil 50, 100 or 200 mg on demand for 12 weeks, without restrictions on food or alcohol. Coprimary endpoints were the change in the proportion of sexual attempts resulting in successful vaginal penetration (SEP2) and successful intercourse (SEP3), and the change in the International Index of Erectile Function — Erectile Function domain (IIEF-EF) score. All three doses were significantly superior to placebo on all coprimary endpoints (p ≤ 0.001). Success rates within 15 minutes of dosing were 64–71% with avanafil versus 27% with placebo. Discontinuations due to adverse events were 1.9–3.1% across avanafil groups. Population considerations. Avanafil is contraindicated in severe hepatic impairment (Child–Pugh class C). In moderate hepatic impairment, the dose should not exceed 50 mg once daily. No dose adjustment is required in mild hepatic impairment. For severe renal impairment (CrCl <30 mL/min), avanafil is not recommended. The REVIVE trial excluded men with diabetes, a history of radical prostatectomy, spinal cord injury, or significant cardiovascular disease, so efficacy in these groups has not been studied in a dedicated phase 3 setting. (EMA Spedra EPAR; NCT00790751)Interactions — why combinations matter
Avanafil potentiates the hypotensive effect of organic nitrates and nitric-oxide donors because both act through the same NO–cGMP pathway in vascular smooth muscle; the combined cGMP elevation can cause dangerous drops in blood pressure. Strong CYP3A4 inhibitors (such as ketoconazole, ritonavir, clarithromycin) markedly increase avanafil plasma concentrations because avanafil is predominantly metabolised by this enzyme. Conversely, CYP3A4 inducers (rifampicin, carbamazepine) reduce exposure and may diminish efficacy. Alpha-blockers also lower blood pressure through a separate mechanism (α1-adrenoceptor blockade), and the additive vasodilatory effect requires careful dose spacing.What has been reported
Storage
Keep in the original package, away from moisture and direct heat, and out of children’s reach. Follow the temperature limit on your pack and do not use it after the expiry date.What to expect
Avanafil is designed for on-demand use and may act within the prescribed pre-sex window, but timing is not a guarantee of response. It requires stimulation and does not address every cause of erectile dysfunction — review several correctly used doses with the doctor.Related reading
For EU authorisation history and the trial evidence behind avanafil, see the avanafil medicine page. See erectile dysfunction for how the underlying condition is assessed, and safety for how doctor review works.Start a consultation
Sexual health consultation
Answer the sexual health questionnaire and a registered doctor reviews it.
They decide whether treatment is appropriate, which one, and at what dose —
and declining is a normal outcome. See what it costs
and how the review works.