A prescription drug (also prescription medication or prescription medicine) is a licensed medicine that is regulated by legislation to require a medical prescription before it can be obtained. The term is used to distinguish it from over-the-counter drugs which can be obtained without a prescription. Different jurisdictions have different definitions of what constitutes a prescription drug.
A prescription is a health-care programme that governs the plan of care for an individual patient and is implemented by a qualified practitioner. A qualified practitioner might be a physician, dentist, nurse practitioner, pharmacist, psychologist, or other health care providers. Prescriptions may include orders to be performed by a patient, caretaker, nurse, pharmacist, physician or other therapist. Prescriptions have legal implications, as they may indicate that the prescriber takes responsibility for the clinical care of the patient and in particular for monitoring efficacy and safety. As medical practice has become increasingly complex, the scope of meaning of the term 'prescription' has broadened to also include clinical assessments, laboratory tests, and imaging studies relevant to optimizing the safety or efficacy of medical treatment.