Prescription medications require a physician's prescription and are intended only for the person for whom they're prescribed, while anyone can buy over-the-counter medicines, according to the U.S. Food and Drug Administration. In addition, the types of regulatory processes governing the two types of medicines differ.
Prescription medications undergo a more strenuous regulatory and approval process than over-the-counter medicines, as the FDA explains. Prescription medicines are only approved for use after they are tested on animal and human subjects. The approval process also includes analysis of how the drugs work in the human body and how they're made. Over-the-counter medicines don't require separate approval if their ingredients, formulations, doses and labeling have already been approved by the FDA.