Agranulocytosis from antiarrhythmic agents. What to watch for when a medication is first prescribed

Anyone who prescribes antiarrhythmic medications should strongly consider monitoring patients for the first 3 months of its use. If agranulocytosis is going to develop, it almost always does so in that period. A complete blood cell count every 1 to 2 weeks can detect neutropenia before symptoms and infectious complications appear. Fever and associated systemic symptoms should always induce evaluation. Treatment involves discontinuation of the causative agent, use of antibiotics and antifungal drugs for infectious complications as needed, and close observation. Spontaneous recovery should occur within 5 weeks. If it does not, a nonpharmacologic cause should be considered.