Safety information · Internal patient-safety page
Avanafil safety summary
Avanafil is the fastest-acting of the PDE5 inhibitors, taken around 15–30 minutes before sex. Like sildenafil and tadalafil it enhances the natural erection response to arousal. It does not cause an erection on its own. The one absolute rule of the class applies in full: never combine it with nitrates.
What it's used for
- Take one tablet about 15–30 minutes before sexual activity.
- Maximum one dose per day.
- Sexual stimulation is still required for it to work.
- A heavy or high-fat meal delays the onset of effect.
Most common side effects
- Headache.
- Flushing of the face.
- Nasal congestion.
- Back pain.
- Dizziness.
Serious side effects: stop and seek care
- An erection lasting more than 4 hours (priapism): go to emergency care; untreated it permanently damages the penis.
- Sudden loss or decrease of vision in one or both eyes: stop and seek urgent care.
- Sudden hearing loss or ringing in the ears.
- Chest pain during or after sex: call emergency services; do not take nitrates.
- Severe allergic reaction (rash, swelling, difficulty breathing).
Who should not take it
- Anyone taking nitrates or nitric-oxide donors (including amyl nitrite 'poppers'): the combination can cause a life-threatening drop in blood pressure.
- Anyone taking riociguat.
- Heart attack or stroke within the last 6 months, unstable angina, or severe heart failure.
- Uncontrolled high blood pressure, or low blood pressure.
- Severe liver or kidney impairment.
- Loss of vision from non-arteritic anterior ischaemic optic neuropathy (NAION) or hereditary retinal disorders.
- Combination with strong CYP3A4 inhibitors such as ketoconazole or ritonavir.
Interactions to flag
- Nitrates and 'poppers': never combine, in any form.
- Alpha-blockers (for prostate or blood pressure): can cause dizziness or fainting; doses need spacing and adjusting.
- Other blood-pressure medicines: additive lowering.
- Strong or moderate CYP3A4 inhibitors: some antibiotics (erythromycin), antifungals (ketoconazole) and HIV medicines raise avanafil levels.
- Grapefruit and grapefruit juice: same effect; avoid them during the 24 hours before taking avanafil.
- Alcohol: increases dizziness and makes an erection harder to achieve.
- Other erectile-dysfunction medicines: never combine.
Message us in the app chat if you notice any of these
- An erection lasting more than 4 hours: go to emergency care first.
- Any sudden change in vision or hearing.
- Chest pain, dizziness or fainting during sex.
- It isn't working after several attempts: the dose or the treatment can be reviewed.
AEMPS CIMA: Avanafil 100 mg
Back to your consultationThis page summarises information from the regulator-approved leaflet for reference only. It is not medical advice and does not replace the assessment of an EU-licensed doctor. Your doctor will review your individual history, dose and interactions during your consultation.