A prescription drug is a standard medical drug that is regulated by legislation to require a prescription before it can be obtained. The term is used to diffrentiate it from over the counter drugs which can be obtained without a precription. Prescription drug has specific definition. Generally over the counter drugs doesn’t require any consent or approval of doctor whereas in the prescription drug doctor approval is must. Prescription drugs are more reliable and non hazardous to health.
Generally a lower dosage of a drug will be approved for over the counter (OTC) use, while higher dosages comes under prescription drug. Distribution of prescription drug always includes package insert, which gives elaborate information about the medicine. Different countries have different rules and regulations related to prescription drug, for example in the United Kingdom they are referred to as Prescription Only Medicine or POM.