Amiodarone prolongs action potential duration (APD) in cardiac tissue. When used long-term, which toxicity requires periodic monitoring by ophthalmological examination?
- A Posterior subcapsular cataract
- B Corneal microdeposits (keratopathy) and rarely optic neuropathy ✓
- C Pigmentary retinopathy
- D Acute angle-closure glaucoma
Explanation
Amiodarone and its active metabolite desethylamiodarone are highly lipophilic iodine-rich compounds that deposit in many tissues. Corneal microdeposits (vortex keratopathy) occur in virtually all patients on long-term amiodarone and are visible on slit-lamp examination as whorl-like deposits; they rarely cause visual symptoms and are not an indication to stop the drug. However, amiodarone can also cause optic neuropathy/optic neuritis in a small percentage, which may lead to permanent visual loss. Routine ophthalmological review is recommended annually. Pigmentary retinopathy is a toxicity of chloroquine/hydroxychloroquine, not amiodarone.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
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Written and medically reviewed by the StethoPrep medical team.