My local chemist has gone off to be fed at her majesties pleasure for fiddling prescriptions. A simple straightforward fraud:
Customer turns up with prescription for a liquid drug.
Chemist says "Not in stock at the moment but I have the same drug in pill form, will that do". Customer says " I suppose so".
Kerching! Liquid medicine is nearly always more expensive than the pill type.
Claim for liquid, supply pills, and repeat, again and again and again.