I used to take Claritin-D for my hay fever. An aside: I switched to Sudafed because I realized that the decongestant was all that I needed, and the loratadine was useless.
Problem is, the decongestant (pseudoephedrine) keeps me awake.
Now, Claritin-D comes in a 12-hour and 24-hour version. I can’t take the 24-hour because then I’ll be up all night & zombified the next day. But at the same time, I’m a normal human so I am awake for 16 hours a day; hence if I take the 12-hour medicine, I’m sniffing & congested for 4 hours a day. Why can’t I buy a 16-hour medicine?
So now, I take Sudafed, which comes in 3-hour increments. But that’s less convenient…