This is an issue for me
In fact, my prescription plan tries to force me to two OTC medications: Prilosec and Claritin.
Fortuantely, (or unfortunately), Prilosec stopped working for me and I have been moved to Protonix and Claritin was ruled out years because because it raises my blood pressure.
They still want to limit the amount of Zyrtec (allergy) medication to 60 pills every 90 days, instead of taking it every day as prescribed. However, I'm allergic to dust and work in very old buildings. In the summer, I end up in 5 or 6 different buildings and during the school year at least 2 others for workshops, etc. And even my own building aggravates my allergies.
Buying OTC is much more expensive than going through doctor and pharmacy service.