Common adverse effects of allopurinol include which of the following?

• A. Dizziness
• B. GI distress
• C. Liver or kidney damage
• D. Headache

Answer: (B)

Allopurinol's common adverse effects are most often related to the gastrointestinal system. The most frequent problem reported with this oral medication is GI distress—nausea, and sometimes vomiting or diarrhea. This makes GI upset the typical side effect you’d expect with standard dosing.

Dizziness and headache can occur, but they’re less common. Liver or kidney damage is not a common, everyday side effect and is more associated with rare hypersensitivity reactions or in patients with preexisting organ dysfunction or certain drug interactions.

So the everyday pattern you’d expect with allopurinol is GI distress, which is why that option fits best.