What is the primary distinction between an over-the-counter (OTC) drug and a prescription drug?

The primary distinction between an over-the-counter (OTC) drug and a prescription drug lies in the requirement for a doctor's authorization. Prescription drugs are medications that can only be dispensed with a valid prescription from a licensed healthcare provider, such as a physician, who has assessed the patient and determined that the medication is necessary for their treatment. This requirement is in place because prescription medications may carry a higher risk of side effects, interactions with other medications, or misuse, necessitating close medical oversight.

On the other hand, OTC drugs are available for purchase without a prescription. They are typically deemed safe and effective for consumers to use for self-diagnosed conditions, assuming that the consumer follows the instructions provided on the packaging. This distinction emphasizes the level of regulation and control concerning how these medications are accessed and used by patients.

The other options do not accurately represent the primary distinction about authorization. OTC drugs can be obtained without the need for a pharmacy, they are not necessarily more effective than prescription drugs, and prescription drugs are not always more expensive than OTC ones. These factors are more related to the context of use and pricing rather than the fundamental regulatory distinction regarding authorization.