- Phenothiazine released in the early 1950s and among the first Antipsychotic agents
- Low potency Dopamine D2 receptor Antagonist (Antipsychotic effect)
- Also blocks Histamine H1 and muscarinic M1 receptors (Antiemetic effect)
- Schizophrenia, Mania or other acute Psychosis
- Adult Oral Dosing
- Start: 25 mg orally three times daily
- Titrate to 400 mg/day in divided doses
- May increase dose 20 to 50 mg/day every few days in severe cases
- Target: 200 to 500 mg/day in most cases (800-1000 mg/day may be needed in some severe cases)
- Maximum: 1000 mg/day in divided doses
- Adult IM Dosing (hospitalized patients)
- Start 24 mg IM
- May repeat 25 to 50 mg IM in next hour
- May increase dose as needed over days to maximum of 400 mg every 4 to 6 hours
- Adult Miscellaneous
- Intractable Hiccups
- Oral: 25 to 50 mg orally every 6 to 8 hours as needed
- IM: 25 to 50 mg IM (if refractory to oral dosing)
- Infusion: 25 to 50 mg in 500 to 1000 ml NS slow IV infusion (if refractory to IM dosing)
- Presurgical Apprehension
- Oral: 25 to 50 mg orally 2 to 3 hours before procedure
- IM: 12.5 to 25 mg IM 1 to 2 hours before procedure
-
Nausea or Vomiting
- Avoid in hypotensive patients
- Oral: 10 to 25 mg orally every 4 to 6 hours as needed
- May increase to 25 to 50 mg every 3 to 4 hours as needed
- IM: 12.5 mg IM for perioperative Nausea, Vomiting
- May repeat 12.5 mg IM dose at 30 minutes if not hypotensive
- IV: 2 mg IV injected over 2 minutes (no faster than 1 mg/min) every 2-3 minutes as needed
- Cummulative maximum: 25 mg
- Use a diluted solution of Chlorpromazine 1 mg/ml
- Acute Intermittent Porphyria
- Oral: 25 to 50 mg orally every 6 to 8 hours as needed
- IM: 25 mg IM every 6 to 8 hours as needed (if patient unable to take oral doses)
-
Tetanus
- IM: 25 to 50 mg IM every 6 to 8 hours
- Infusion: 25 to 50 mg in 500 to 1000 ml NS slow IV infusion (no faster than 1 mg/ml)
- Children
- Alpha adrenergic blockade
-
Anticholinergic Symptoms
- Dry Mouth
- Sedation
- Extrapyramidal Side Effects
- Hyperprolactinemia
- Weight gain and Glucose Intolerance
- QTc Prolongation
- Potentiates Central Nervous System Depressants (e.g. Alcohol, Opioids) with apnea risk
- Metabolized by CYPA12, CYP2D6 and CYP3A4
- Chlorpromazine (DailyMed)
- Chlorpromazine (Stat Pearls)
- Mann (2022) Chlorpromazine, StatPearls, Treasure Island
- (2016) Med Lett Drugs Ther 58(1510): 160-5
- Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 42-3
- Hamilton (2020) Tarascon Pocket Pharmacopoeia