Well... Meds alone won't fix the problem. I usually treat bruxism with an anterior bite plane worn 24x7 for 2 weeks which then goes to night-time wear only after the first two weeks. I also usually prescribe a steroid (medrol (methylprednisolone) dose pack) for the first week of therapy. This works 99% of the time. If that doesn't do the trick, there are other meds as a 2nd line therapy, .
Best treatment. Bruxism does not necessarily need to be treated unless there is damage to the dentition and/or facial pain. There are some medications that help such as clonazepam, gabapentin, and clonadine but the best first treatment is an oral splint made by a dentist familiar with these disorders.