A half man half horse is standing in at a  pharmacist counter. The pharmacist is handing up a bottle of medicine.
There is no such thing as a half man and a half horse.
Why does the man need medicine?
Looks like you're already familiar with the side effects.
scene: pharmacy description: A half man half horse is standing in at a pharmacist counter. The pharmacist is handing up a bottle of medicine. uncanny: There is no such thing as a half man and a half horse. entities: Centaur, Pharmacist. caption: Looks like you're already familiar with the side effects.
The side effect of this man's prescription drug is that it turns him into a centaur. This funny part is how nonchalant the pharmacist is about this side effect: her response is as if she sees this very unusual side effect quite regularly, and it's not a big deal. Apparently, the only action required is to be familiar with the side effect, as if it were a more benign one like drowsiness.