In medical abbreviations, PRN means:

• A. When necessary
• B. Immediately
• C. Before meals
• D. After meals

Answer: (A)

PRN means a medication is given as needed, in response to the patient’s symptoms, rather than on a fixed schedule. The Latin term pro re nata translates to “as needed.” This approach is common for relief-based drugs like pain medications or antiemetics, where a dose is given when the patient reports symptoms or when symptoms recur, often with a specified maximum daily dose and a minimum interval between doses to keep usage safe. The idea is to treat the symptom when it occurs rather than giving doses automatically. Immediate administration describes urgent action for acute situations and is not what PRN conveys, while before or after meals refers to fixed timing around meals, not symptom-driven use.