Managing Side Effects: What to Expect When You Start Treatment for Erectile Dysfunction

How ED medications work

The most commonly prescribed ED treatments in the UK are PDE5 inhibitors, which include sildenafil (the active ingredient in Viagra), tadalafil (Cialis), and vardenafil (Levitra). They work by relaxing the blood vessels in the penis, increasing blood flow when you're sexually aroused. They don't cause an automatic erection — arousal is still needed.

Common side effects

Most side effects are mild, temporary, and tend to ease as your body adjusts to the medication. The most frequently reported include:

•  Headache — the most common side effect, caused by the blood vessel-relaxing action of the medication. Usually mild and can be managed with paracetamol

• Facial flushing — a warm, red feeling in the face and neck. This is harmless and typically passes within a few hours

• Nasal congestion — a blocked or stuffy nose, again caused by blood vessel dilation

• Indigestion or heartburn — taking the medication with food can sometimes help, though sildenafil works best on an empty stomach

• Dizziness — usually mild. Avoid standing up too quickly and don't combine ED medication with excessive alcohol

How long do the effects (and side effects) last?

 This depends on which medication you're taking. Sildenafil typically lasts four to six hours, while tadalafil can remain effective for up to 36 hours (which is why it's sometimes called the "weekend pill"). Side effects usually follow a similar timeline — they peak within the first couple of hours and then gradually fade.