What is a drug interaction and can you give a common example?

• A. An alteration of effect when two meds interact; e.g., NSAIDs with anticoagulants increasing bleeding risk.
• B. A medication that cures two diseases at once.
• C. When two drugs cancel each other's effects completely.
• D. A drug that only works when taken with food.

Answer: (B)

Drug interaction means two medicines influence each other’s effects, changing how strong or how long each one works. This can make a drug work more than usual, less than usual, or produce a new effect. A common example is taking NSAIDs with an anticoagulant like warfarin; NSAIDs can affect platelets and increase bleeding risk, while the anticoagulant slows clotting—together they alter the overall effect and raise harm risk.

Other statements don’t describe an interaction. It’s not about a medicine curing two diseases at once, nor about two drugs completely canceling each other’s effects, and it isn’t about a drug that only works with food.