What does the prescription abbreviation PRN stand for?

• A. Immediately
• B. As needed
• C. As directed
• D. With meals

Answer: (B)

PRN means you take the medication as needed based on symptoms, not on a fixed schedule. This abbreviation comes from the Latin pro re nata and is used to signal symptom-driven dosing. It matters in practice because you use the drug only when you’re experiencing the specified symptom (for example, pain), and you stay within the prescribed limits for how often and how much you can take.

Think of a pain reliever prescribed PRN: you don’t take it every hour or every day unless you have pain; you assess your symptoms and use it accordingly, obeying the maximum daily dose and any minimum interval between doses.

The other phrases describe different dosing ideas: taking a drug immediately implies urgent or on-the-spot action, following “as directed” means sticking to the exact schedule given by the clinician rather than responding to symptoms, and “with meals” refers to timing relative to eating, not to symptom-triggered use.