For me, 24-hour Claritin will usually dry me out for 16-20 hours. Does fuck-all for any other symptoms, but runny nose is the one I hate, so it’s a primary weapon in my arsenal. If my nose is running, I can’t sleep, it makes a mess, and unless I’m religious about fancy kleenex I will end up with a rash on my nose or upper lip. Ending the runny nose makes a cold much more bearable for me.