Over-the-counter (OTC) drugs are medicines that may be purchased by a consumer directly from a healthcare professional without a prescription. In many countries, OTC drugs are chosen by a regulatory agency to certify that the particular ingredients contained in the drug, are safe and effective when used without a physician’s care.

See also:
Prescribing information
Prescribing Analysis and Cost (PACT)
Food And Drug Administration (FDA)
European Medicines Agency