you're most likely taking it as an injection, chewing on it, or smoking it. If you were to put it in a capsule (you can buy capsules) and swallow it, you may not get this side effect. I only know this because when I chewed on adderall, I'd get impotent, even with cialis. Doesn't matter now, since I'm impotent from high doses of effexor, although prolonged use of meth can also lead to the need to consider what I'm considering: prosthetic penile implant. It gets hard when you push a button underneath your crotch. fml. avoid amphetamines.