Section 02 · Monograph
Chlorpromazine
Reviewed Nov 2026FDA label
ThorazinePhenothiazine antipsychotic
- Forms
- Tab: 10, 25, 50, 100, 200mg | IV/IM: 25mg/mL
- Dose
- Acute migraine (off-label): 12.5mg IV every 15 min up to 37.5mg, or 25-50mg IM; usually with IV fluids
- MOA
- D2, H1, α1 and muscarinic blockade
Black Box Warning
- Increased mortality in elderly patients with dementia-related psychosis
Indications
- Schizophrenia, nausea and vomiting, intractable hiccups, acute intermittent porphyria, tetanus adjunct, preoperative apprehensionFDA-labeled
Off-Label Uses
- Acute migraine in the emergency departmentOff-label
Mechanism of Action
- Phenothiazine with D2, H1, alpha-1 adrenergic and muscarinic blockade producing antiemetic, sedative and antimigraine effects
Full Dosing
Adult / usual
- Acute migraine (off-label): 12.5mg IV every 15 minutes up to 37.5mg, usually with an IV fluid bolus; or 25-50mg IM
- Observe closely for hypotension and sedation; consider diphenhydramine to prevent dystonia
Contraindications
- Comatose states or severe CNS depression
- Known hypersensitivity to phenothiazines
- Pediatric patients with Reye's syndrome (relative)
Drug Interactions
- Additive CNS depression with opioids, alcohol and benzodiazepines
- QT-prolonging drugs increase arrhythmia risk
- Anticholinergic and antihypertensive effects are additive
Adverse Effects
- Hypotension (especially IV), sedation
- Extrapyramidal reactions including acute dystonia and akathisia
- QT prolongation
- Anticholinergic effects
- Tardive dyskinesia and neuroleptic malignant syndrome
Monitoring Parameters
- Blood pressure
- ECG/QTc if risk factors
- Extrapyramidal symptoms
Pregnancy & Lactation
- Neonatal extrapyramidal and withdrawal symptoms with late-pregnancy exposure
- Present in milk; use caution