Prophylactic drugs are designed to maintain a healthy state by preventing disease.

• A. Maintain a healthy state by preventing disease
• B. Cure infection
• C. Relieve symptoms
• D. Diagnose disease

Answer: (A)

Prophylactic therapy is preventive medicine: it aims to keep someone healthy by reducing the chance that disease will develop. These drugs are used before illness occurs, in situations where there’s a known risk, to stop problems from arising (for example, antibiotics to prevent infection around surgery or vaccines that prime the immune system).

That makes the best choice the one that states maintaining a healthy state by preventing disease. The other ideas describe different roles: curing an active infection is therapeutic treatment, not prevention; relieving symptoms happens after disease is present; and diagnosing disease involves identifying a condition, not preventing it.