Chlorpromazine

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)

Adult Oral Dosing
1. Start: 25 mg orally three times daily
2. Titrate to 400 mg/day in divided doses
  1. May increase dose 20 to 50 mg/day every few days in severe cases
3. Target: 200 to 500 mg/day in most cases (800-1000 mg/day may be needed in some severe cases)
4. Maximum: 1000 mg/day in divided doses
Adult IM Dosing (hospitalized patients)
1. Start 24 mg IM
2. May repeat 25 to 50 mg IM in next hour
3. May increase dose as needed over days to maximum of 400 mg every 4 to 6 hours

Intractable Hiccups
1. Oral: 25 to 50 mg orally every 6 to 8 hours as needed
2. IM: 25 to 50 mg IM (if refractory to oral dosing)
3. Infusion: 25 to 50 mg in 500 to 1000 ml NS slow IV infusion (if refractory to IM dosing)
Presurgical Apprehension
1. Oral: 25 to 50 mg orally 2 to 3 hours before procedure
2. IM: 12.5 to 25 mg IM 1 to 2 hours before procedure
Nausea or Vomiting
1. Avoid in hypotensive patients
2. Oral: 10 to 25 mg orally every 4 to 6 hours as needed
  1. May increase to 25 to 50 mg every 3 to 4 hours as needed
3. IM: 12.5 mg IM for perioperative Nausea, Vomiting
  1. May repeat 12.5 mg IM dose at 30 minutes if not hypotensive
4. IV: 2 mg IV injected over 2 minutes (no faster than 1 mg/min) every 2-3 minutes as needed
  1. Cummulative maximum: 25 mg
  2. Use a diluted solution of Chlorpromazine 1 mg/ml
Acute Intermittent Porphyria
1. Oral: 25 to 50 mg orally every 6 to 8 hours as needed
2. IM: 25 mg IM every 6 to 8 hours as needed (if patient unable to take oral doses)
Tetanus
1. IM: 25 to 50 mg IM every 6 to 8 hours
2. Infusion: 25 to 50 mg in 500 to 1000 ml NS slow IV infusion (no faster than 1 mg/ml)

Indications
1. Psychosis or severe behavioral disorder
2. Nausea or Vomiting
Dosing (age 6 months to 12 years)
1. Oral: 0.55 mg/kg orally every 4 to 6 hours
2. IM: 0.55 mg/kg IM every 6 to 8 hours
  1. Maximum IM dose up to age 5 years (23 kg): 40 mg/day
  2. Maximum IM dose up to age 5 to 12 years (23 to 46 kg): 75 mg/day

Potentiates Central Nervous System Depressants (e.g. Alcohol, Opioids) with apnea risk
Metabolized by CYPA12, CYP2D6 and CYP3A4