Which set of chronic adverse effects is classically associated with long-term phenytoin therapy?

• A Nephrolithiasis, metabolic acidosis, and paresthesias
• B Weight gain, alopecia, and pancreatitis
• C Hyponatraemia, osteomalacia, and leukopenia
• D Gingival hyperplasia, hirsutism, and megaloblastic anaemia ✓

Explanation

Phenytoin causes gingival hyperplasia through fibroblast proliferation, hirsutism, and folate deficiency leading to megaloblastic anaemia. It also induces vitamin A metabolism causing osteomalacia, but hyponatraemia is typical of carbamazepine and oxcarbazepine, while nephrolithiasis and acidosis belong to topiramate and acetazolamide. Recognising these drug-specific clusters is standard examination material.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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