Clozapine is prescribed for a patient with treatment-resistant schizophrenia. The mandatory baseline investigation and the life-threatening adverse effect it monitors are:

• A Liver function tests — hepatic necrosis
• B ECG — QTc prolongation and torsades de pointes
• C Absolute neutrophil count — agranulocytosis ✓
• D Renal function tests — interstitial nephritis

Explanation

Clozapine carries a 1–2% risk of potentially fatal agranulocytosis, necessitating mandatory monitoring of absolute neutrophil count (ANC) before initiation and regularly throughout therapy (weekly for 6 months, then fortnightly, then monthly). Drug must be discontinued if ANC falls below 1500/mm3. Clozapine also causes metabolic syndrome, myocarditis, and excessive salivation, but agranulocytosis is the most critical safety concern.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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