In the US, prescription and OTC are theoretically completely unrelated, but in practice patent holders want their drugs to be prescription, where end users aren

In the US, prescription and OTC are theoretically completely unrelated, but in practice patent holders want their drugs to be prescription, where end users aren't involved in the process of selecting or paying for the drug, whereas generic manufacturers want the drugs to be OTC, where end users are choosing the product in a competitive market. See, for example, Prilosec (Omeprazole) switching from prescription to OTC.