Phosphodiesterase-5 inhibitors, such as sildenafil (for example, Viagra), have made a big difference in the treatment of erection problems (erectile dysfunction). But they can cause life-threatening side effects for anyone who also takes nitroglycerin or another medicine containing an organic nitrate. This combination can make your blood pressure fall too low. This can possibly cause a stroke, a heart attack, or death. Do not take nitrate medicines up to 24 hours after you take sildenafil (for example, Viagra) or vardenafil (for example, Levitra). Do not take nitrate medicines up to 48 hours after you take tadalafil (for example, Cialis).
Medicines that contain organic nitrates include:
- Nitroglycerin (such as Nitro-Dur, Nitrolingual, Nitrostat).
- Isosorbide (such as Dilatrate, Isordil).
- Nitroprusside (such as Nitropress).
- Amyl nitrite or amyl nitrate. These are sometimes called "poppers." They are sometimes abused.
Nitrates found in foods are not a danger when taking phosphodiesterase-5 inhibitors.