Is it safe having sildenafil with lsd or mdma pills?
There are no reported cases of severe toxicity mixing MDMA or LSD and sildelnafil. The combination is “probably” (but not “absolutely”) safe. The risk of problems or adverse effects depends on dosage, timing, previous experience with both substances and personal characteristics. It is possible (at least theoretically) some “rebound” effect between vasoconstrictor properties of amphetamines and vasodilator of sildenafil. Moderate dosages of both substances diminish the risk of problems. The most dangerous combination, as 2fruits said, is between PDE-5 inhibitors (Viagra, Cialis, Levitra…) and poppers.