Hello doctor, i suffer from allergies & have been prescribed medicines for that but the issue is i get sleep attacks from all of those drugs i have tried which are montek-lc, levocetrizine or even Allegra. In all of these drugs, i feel sleepy throughout the next day. I even tried taking them in the afternoon the previous day but still i get sleep throughout next day. Which drug doesn't cause sleep? Please help as i can't function at all on all these drugs.