Has the drug Vynanse (an ADD drug) been known to cause severe leg cramps? I ve been on the drug for about 6 months now; I m 56 years old. I use to get leg cramps occasionally (3-4 times a year; the pain was moderate) but since taking Vynanse, I get leg cramps about twice a month. They are excruciating; I cannot walk or even get up off the floor. The last time this occurred, about 2 weeks ago, I went into my bedroom closet, shut the door, and yelled in agony - something I never thought I d do. The cramps last about 15 minutes, stop for about 30 seconds, then start up again. This continues for about an hour. Thanks for your insight.