All ED medications in the PDE5 inhibitor class — sildenafil, tadalafil, vardenafil, and avanafil — share a similar side effect profile because they work in the same way. Most side effects are mild, predictable, and short-lived, but it is important to be informed before starting treatment.
Common Side Effects
The following side effects occur in more than 1 in 10 men taking PDE5 inhibitors:
- Headache — the most frequently reported side effect, caused by blood vessel dilation
- Facial flushing — a warm, red feeling in the face and neck
- Nasal congestion — a stuffy or blocked nose
- Indigestion or dyspepsia — stomach discomfort, particularly with tadalafil
Less Common Side Effects
These affect fewer than 1 in 10 men:
- Dizziness — due to a mild drop in blood pressure
- Visual disturbances — a blue tint or increased light sensitivity, more common with sildenafil
- Back pain and muscle aches — particularly associated with tadalafil
- Nausea
Rare but Serious Side Effects
Seek immediate medical attention if you experience:
- Priapism — an erection lasting more than four hours. This is a medical emergency that can cause permanent damage if untreated
- Sudden vision loss — may indicate non-arteritic anterior ischaemic optic neuropathy (NAION)
- Sudden hearing loss — sometimes accompanied by tinnitus or dizziness
- Chest pain during or after sex — stop activity and call 999; do not take GTN if you have taken a PDE5 inhibitor
Tips for Managing Side Effects
- Start with the lowest effective dose — your prescriber may begin at 50 mg sildenafil or 10 mg tadalafil and adjust from there
- Stay hydrated — drinking water can reduce headache and flushing
- Avoid excess alcohol — alcohol can worsen side effects and reduce the medication's effectiveness
- Take with or after food — for tadalafil, this can reduce indigestion
- Give it time — some side effects diminish after the first few uses as your body adjusts
When to Speak to Your Doctor
If side effects are persistent or bothersome, speak to your GP or prescriber. Switching to a different PDE5 inhibitor or adjusting the dose often resolves the issue. Never stop prescribed medication without medical advice.