Sildenafil and tadalafil are the two most widely prescribed treatments for erectile dysfunction. Both have a long track record, and both are sold as cheaper generics. The question that matters is often not ed meds online which one is "better", but which one matches your plans.

Sildenafil is normally taken about an hour before sex and works for four to five hours. A heavy meal can delay the effect. Tadalafil, on the other hand, can work for up to 36 hours, and food has little effect. Plenty of men also take a low daily dose of tadalafil so they do not have to plan ahead.

If you want a simple comparison, this practical guide walks through timing, food and side effects.

A few safety points: never take either medicine with nitrate heart medicines or with "poppers". Tell your doctor about any other medicines you take. Common side effects are headache, flushing, a blocked nose and indigestion. Seek medical help straight away for an erection lasting more than four hours or sudden changes in vision.

Do not chase higher strengths. The licensed doses are 25, 50 or 100 mg for sildenafil and 2.5 to 20 mg for tadalafil. Bigger doses do not reliably work better, but they do raise the risk of side effects. Stick to the dose on your prescription.

When you buy medicine online, check the strength on the pack and keep the leaflet. A valid prescription is required for every order of a prescription medicine. You can read more on this page.

This article is for general information only. Always check with your doctor before starting a new medicine.