Fexofenadine
"I have used anything from chlorpheniramine to claritin to zyrtec and then telfast by far telfast is the only one that didn't make me overly drowsy.

Just this morning I woke up feeling miserable stuck nose and sneezing like over 10 times and heavy headed. I popped a pill and went to work and within an hour I was almost good as new. Throughout the day I was very productive and not once dozy. With my nose not running a bit, I even had the energy to run a 10km in the evening myself!!!"