chlorpromazine

General information

• Class: Antipsychotic
• Common US brands: Thorazine
• Typical dose range: Dosing is individualized by indication and setting. The label emphasizes gradual titration until symptoms are controlled, then step-down to the lowest effective maintenance dose (label).
• Therapeutic drug monitoring not routinely recommended.
• Last reviewed: 2026-02-22

Dosing & forms

• Forms/strengths: Oral tablets: 10 mg, 25 mg, 50 mg, 100 mg, 200 mg (manufacturer-dependent); label notes higher strengths for severe neuropsychiatric conditions.; Other formulations (outside this page’s focus) include injections and oral concentrates in some labeling/manufacturer catalogs (label-dependent).
• Frequency: Psychotic disorders: label examples include outpatient starts such as 10 mg three or four times daily or 25 mg two or three times daily; more severe cases may be titrated upward in semi-weekly intervals (label).
• Typical range: Dosing is individualized by indication and setting. The label emphasizes gradual titration until symptoms are controlled, then step-down to the lowest effective maintenance dose (label).

Mechanism (brief)

Low-potency phenothiazine first-generation antipsychotic (D2 antagonism) with prominent antihistamine (H1) and anticholinergic effects; often associated with sedation and orthostatic hypotension.

Metabolism & Half‑life

• Metabolism: Hepatic metabolism
• Half‑life: —

Therapeutic Drug Monitoring (TDM)

Recommended: No

Monitoring highlights

• Sedation and functional impairment (falls risk, driving safety).
• Orthostatic symptoms and blood pressure (especially early titration).
• Anticholinergic effects (bowel/urinary symptoms, delirium risk).
• Movement symptoms (akathisia, rigidity, tremor; tardive dyskinesia screening).
• Weight and cardiometabolic risk factors over time.

Sources

• Chlorpromazine hydrochloride tablets prescribing information — DailyMed (2025)
• First-Generation Versus Second-Generation Antipsychotics in Adults: Comparative Effectiveness — Agency for Healthcare Research and Quality (NCBI Bookshelf) (2012)
• The American Psychiatric Association Practice Guideline for the Treatment of Patients With Schizophrenia — American Psychiatric Association (2020)
• AGNP Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology — Pharmacopsychiatry (2018)