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Clozapine

SGA • Brands: Clozaril

Last reviewed: 2025-09-23

General information

Indicated for: Clozapine tablets are an atypical antipsychotic indicated for: Treatment-resistant schizophrenia. Efficacy was established in an active-controlled study. (1.1 , 14.1) Reducing suicidal behavior in patients with schizophrenia or schizoaffective disorder. Efficacy was established in an active-controlled study. (1.2 , 14.2)

Dosing & forms

  • Forms/strengths: —
  • Frequency: —
  • Food: —
  • Typical range: 300–600 mg/day (target), up to 900 mg/day
  • Therapeutic range: 350–600 ng/mL

Mechanism (brief)

Low D2 affinity; higher D4; serotonergic, adrenergic, histaminergic, and anticholinergic activity.

Metabolism & Half‑life

  • Metabolism: Primarily CYP1A2 (also 3A4, 2D6). Smoking induces clearance.
  • Half‑life: ~12 h (steady state ~12–16 h).

Therapeutic Drug Monitoring (TDM)

Recommended: Yes

Reference range: 350–600 ng/mL

Sampling: 12‑h trough (or pre‑AM dose)

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Monitoring highlights

  • ANC monitoring (REMS program) — Weekly x6 mo; q2w x6 mo; monthly thereafter
  • Metabolic: weight, BMI, fasting lipids/glucose — Baseline, 3 mo, annually

In‑depth reading

Sources