My old prescription says I can take one twice a day. I've taken three today and I can feel a sleepy effect, but not enough to nod off. That's probably because it's been a while. Right after I took the third, I nodded off at the computer. LOL Reminded me of my first pregnancy. Lordy, that was awful!! And my boss had the gall to tell me not to get pregnant... and here I sat almost in front of her nodding off. LOL Yeah, I got fired! I was glad 'cause I got to stay home and sleep whenever I felt like it.