Chlorpromazine

THORAZINE

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What it isLow-potency first-generation antipsychotic with broad D2, histamine, alpha-1, muscarinic, and serotonin blockade; schizophrenia.

Why this oneIt also treats intractable hiccups and severe nausea—an unusually broad clinical niche for an antipsychotic.

What limits itOrthostatic hypotension and anticholinergic burden exceed the extrapyramidal risk. Photosensitivity and corneal deposits emerge with long use.

FDA-approved for

schizophrenia (1954)
nausea/vomiting (~1957)

Off-label

migraine and headache in the emergency department

FDA label

Read the full label on DailyMed ↗

BOXED WARNING Increased mortality in elderly patients with dementia-related psychosis; not approved for dementia-related psychosis.

FDA dosing	Population	Start	Target	Max
Psychotic disorders (schizophrenia/mania), outpatient	Adults	10 mg TID–QID or 25 mg BID–TID	~400 mg/day	800 mg/day (higher not uncommon)
Psychotic disorders, hospitalized acute schizophrenic/manic	Adults	25 mg TID	~500 mg/day	2000 mg/day (little gain >1000)
Nausea and vomiting	Adults	10–25 mg q4–6h PRN	10–25 mg q4–6h PRN
Intractable hiccups	Adults	25–50 mg TID–QID	25–50 mg TID–QID
Presurgical apprehension	Adults	25–50 mg 2–3h pre-op	25–50 mg 2–3h pre-op
Acute intermittent porphyria	Adults	25–50 mg TID–QID	25–50 mg TID–QID
Severe behavioral problems	Children 6 mo–12 yr	0.25 mg/lb q4–6h PRN	50–100 mg/day (older children up to 200 mg/day+)	500 mg/day (retarded pts)
Nausea and vomiting	Children 6 mo–12 yr	0.25 mg/lb q4–6h	0.25 mg/lb q4–6h

Titration Increase by 20–50 mg at semi-weekly intervals (more severe adult cases)

Renal Undefined

Hepatic Undefined

Instructions

Increase dose gradually until symptoms controlled; more gradually in elderly/debilitated/emaciated
After control, gradually reduce to lowest effective maintenance dose
Acute states: often initiated with IM/IV, then substitute oral
Not for pediatric patients <6 months except where potentially lifesaving

Contraindications

Comatose states or presence of large amounts of CNS depressants (alcohol, barbiturates, narcotics)

Cautions

Neuroleptic malignant syndrome, tardive dyskinesia, extrapyramidal reactions
Hypotension (esp. postural); caution in cardiovascular disease
Cholestatic jaundice (usually 2nd–4th week; sensitivity reaction) — caution in liver disease
Hematologic: agranulocytosis, leukopenia — watch weeks 4–10; report sore throat/infection

Adverse reactions

Drowsiness (esp. first 1–2 weeks)
Postural hypotension, tachycardia, dizziness, fainting
Jaundice (cholestatic)
Hematologic disorders: agranulocytosis, leukopenia, hemolytic/aplastic anemia, thrombocytopenic purpura

Pregnancy Undefined

Lactation Undefined

⚠ BOXED WARNING

Increased mortality in elderly patients with dementia-related psychosis

Cost, est. cash$5–$150/month

Generic entry1982

Classes and tags

Clinical profile

Therapeutic safety burden2 / 4

Overdose danger2 / 4

Weight-gain liability3 / 4

Sedation liability3 / 4

QT / Torsades3 / 4

Direct muscarinic antagonism3 / 4

Embryofetal risk2 / 4

Legacy pregnancy categoryC

Defining liabilityMetabolic effects, extrapyramidal symptoms/tardive dyskinesia and agent-specific QT or orthostatic risk.

Mechanism of action: Chlorpromazine ballicule

Chlorpromazine ballicule: receptor binding, kinetics and half-life diagram

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Memory aids: mascots and interaction avatars

Chlorpromazine THORAZINE mascot mnemonic cartoon — **“Thor’s Color promising”**
Photosensitive skin discoloration
Polka dots on pink → α1 blocker → syncope if titrated too quickly (hit the floor)
Spooky mascot → antipsychotic

CYP2D6 substrate

Open Chlorpromazine in the interactive console ↗