What information must be included on a written prescription for a drug?

The correct choice emphasizes the essential components that must be included on a written prescription to ensure safe and effective medication use. A prescription serves as a communication tool between the prescriber and the pharmacist, hence it must include critical information.

The drug name is necessary so the pharmacist knows exactly which medication to dispense. The dosage form identifies the specific form in which the medication is to be administered, such as tablet, capsule, or liquid. Directions for use provide clear instructions on how the patient should take the medication, which is vital for proper administration and effectiveness. Lastly, the quantity prescribed indicates how much medication the patient should receive, which is crucial for treatment adherence and management of refills.

Including these elements ensures that both the pharmacist and patient have a clear understanding of the prescription, which enhances patient safety and medication effectiveness. This level of detail is required by law in many jurisdictions, such as Virginia, to minimize the risk of medication errors and miscommunication.