What are PDE5 inhibitors?
PDE5 inhibitors are prescription medicines that work by blocking an enzyme called phosphodiesterase type 5. This helps blood vessels in the penis relax in response to sexual stimulation. They do not cause an erection without arousal.
Medicines in this class
Common examples include sildenafil, tadalafil, vardenafil and avanafil. They differ mainly in how quickly they act and how long their effect lasts.
Important safety warning: nitrates
PDE5 inhibitors must not be combined with nitrate medicines (such as those used for chest pain/angina) or certain other drugs, because the combination can cause a dangerous drop in blood pressure.
Other precautions
They may not be suitable for people with certain heart conditions, very low or uncontrolled blood pressure, recent stroke or heart attack, or some eye and liver conditions. Side effects can include headache, flushing, indigestion and nasal congestion.
Talk to a professional
Only a qualified healthcare professional can assess whether a medicine is appropriate. This page does not recommend doses or treatment regimens.