American Board of Internal Medicine (ABIM) Certification Practice Exam

What class of medication is commonly used for managing gout but has contraindications with diltiazem?

1. Non-steroidal anti-inflammatory drugs

2. Xanthine oxidase inhibitors

3. Colchicine

4. Glucocorticoids

The correct answer is: Colchicine

Colchicine is a medication frequently used to manage acute attacks of gout as well as for prophylaxis in patients with chronic gout. Its utility stems from its ability to reduce inflammation associated with gout flares without being a traditional non-steroidal anti-inflammatory drug (NSAID). When considering the interaction with diltiazem, a calcium channel blocker primarily used for hypertension and certain heart conditions, colchicine is notable for its specific contraindications. Both colchicine and diltiazem are metabolized by the liver, particularly through the CYP3A4 enzyme pathway. When taken together, the risk of colchicine toxicity increases due to diltiazem's effect on this metabolic pathway, potentially leading to dangerous side effects, including gastrointestinal issues and central nervous system toxicity. Other medications listed such as NSAIDs, xanthine oxidase inhibitors, and glucocorticoids do not have the same significant interaction profile with diltiazem, making colchicine unique in this aspect when it comes to their concurrent use. Therefore, prioritizing safety when prescribing is crucial, and that's why colchicine's interaction with diltiazem is a vital consideration in clinical practice.