I am on Keppra, 1000mg am, 1500 mg pm, and gabapentin 300 mg am/pm, for epilepsy, paxil 30 mg for hot flashes, Zyrtec 10 mg for allergies. I ve noticed i get sudden diarrhea (loose stools) and then i get black tarry stools (not every time, but once a month) after the diarrhea. Is this side effects from the medications? I have had an upper and lower GI test, with only internal hemorrhoids.