I Have Been Taken Levetiracetam 500 Mg For 3 1/2

I have been taken levetiracetam 500 mg for 3 1/2 years however, now after taking 1 pill, 6 hours later I have diarrhea. I started taking equate anti-diarrheal 2mg twice a week, which has helped. Is this safe, I want to continue using Keppra, I have not had any focal seizures during the 3 1/2 years.