A patient with atrial fibrillation develops symmetric arthralgia, myalgia, and a positive ANA after starting a class IA antiarrhythmic. Which drug is most likely responsible?
- A Quinidine
- B Procainamide ✓
- C Flecainide
- D Sotalol
Correct answer: B. Procainamide
Explanation
Procainamide is well known for causing a drug-induced lupus-like syndrome, characterized by arthralgia, myalgia, and a positive ANA, especially in slow acetylators. Quinidine is more associated with cinchonism (tinnitus, headache) and thrombocytopenia, rather than a lupus-like reaction.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.