Don't take with...

Alcohol

If tadalafil is taken with alcohol it causes a drop in blood pressure, that leads to dizziness. Moreover, alcohol impairs sexual performance.

Any form of nitrate medication

Causes a severe drop in blood pressure. Might lead to dizziness, fainting, or even a heart attack. Don't use Tadalafil in case that you take: glyceryl trinitrate, isosorbide mononitrate or isosorbide dinitrate (angina and heart failure treatments), amyl nitrate and nicorandil.

Tadalafil will be less effective with...

Medicines that speed up the breakdown of tadalafil by the liver: phenytoin, carbamazepine, phenobarbital and rifampicin.