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Chlorpromazine

Brands and Forms

  • Thorazine
    • tablet: 10mg, 25mg, 50mg, 100mg, 200mg
    • capsule: 30mg, 75mg, 150mg
    • ampul: 25mg/ml
    • vial: 25mg/ml
    • liquid: 10mg/5ml
    • suppository: 25mg, 100mg
  • Largactil
    • tablet: 10mg, 25mg, 50mg, 100mg, 200mg

Uses of Chlorpromazine

In psychiatry, Chlorpromazine can be used for treating Psychotic Disorders including Schizophrenia, and Manic and Mixed Episodes in Bipolar Disorder.

In general medicine, Chlorpromazine is used for nausea and vomiting, restlessness and apprehension before surgery, acute intermittent porphyria, tetanus, and intractable hiccups.

How Chlorpromazine Works

Chlorpromazine is a low-potency Typical Antipsychotic. It is an antagonist at: dopamine D1, D2, D3 and D4 receptors; serotonin 1 and 2 receptors; histamine H1 receptors; adrenergic α1 and α2 receptors; muscarinic M1 and M2 acetylcholine receptors.

Cautions when Using Chlorpromazine

In elderly individuals with Dementia, use of antipsychotics has been associated with increased rates of sudden death. It is unclear whether the antipsychotic use is a cause, or simply a marker, of deteriorating health in these individuals.

Individuals with Parkinson disease or Lewy-Body Dementia may have increased sensitivity to Chlorpromazine, which may manifest as confusion, obtundation, severe extrapyramidal symptoms, and neuroleptic malignant syndrome.

In people with pre-existing heart disease, glaucoma, seizure disorders, brain damage, or hepatic or renal function impairment, advice from the appropriate medical specialist should be obtained before starting Chlorpromazine.

Patients who are unfamiliar with the effects of Chlorpromazine should avoid driving or operating heavy machinery when starting this medication.

Use caution when combining this medication with other CNS depressants.

People taking this medication should avoid extreme heat exposure.

Dosing of Chlorpromazine

For treating psychosis and Manic or Mixed Episodes, the usual therapeutic dose range is 200-800mg/day, given in divided doses 2-4 times per day. In some cases up to 2000mg/day may be needed. It can be started at 25-50mg three times a day, and then increased quite quickly as needed until symptoms come under control.

Lower doses tend to give more sedative action than antipsychotic action.

When wanting to stop this medication, the dose should be decreased gradually over a period of 6-8 weeks.

Onset of action

Manic and psychotic symptoms can improve within 1 week of use, but full therapeutic effect in Bipolar Disorder and Psychotic Disorders may take several weeks. If there is no significant effect after 4 weeks at the maximum tolerated dose, then it may not work at all.

Acute agitation can improve after a single dose.

Kidney impairment

Use with caution.

Liver impairment

Use with caution.

Side-effects of Chlorpromazine

Below is a list of most of the reported side-effects of Chlorpromazine. Most of these side-effects occur in only a minority of individuals, and many also resolve with time while the medication is continued.

Cardiovascular: Orthostatic hypotension; hypertension; tachycardia; bradycardia; syncope; circulatory collapse; ECG changes.

Central Nervous System: faintness; drowsiness (can be very significant); extrapyramidal symptoms; headache; weakness; tremor; fatigue; slurring; insomnia; vertigo; seizures; neuroleptic malignant syndrome; cerebral edema.

Dermatologic: photosensitivity; skin pigmentation; dry skin; rash.

Endocrine/Metabolic: increased appetite and weight gain; elevated cholesterol; decreased sweating; heat stroke; elevated prolactin.

Eyes, Ears, Nose and Throat: blurred vision; dry mouth; pigmentary retinopathy; glaucoma; photophobia; increased intraocular pressure; mydriasis; nasal congestion; miosis.

Gastrointestinal: dyspepsia; constipation; intestinal obstruction; nausea; jaundice.

Genitourinary: urinary retention and hesitancy; impotence; sexual dysfunction; menstrual irregularities; lactation; moderate breast engorgement; priapism; breast enlargement; galactorrhea.

Hematologic: agranulocytosis; eosinophilia; leukopenia; hemolytic anemia; thrombocytopenic purpura; pancytopenia.

Psychiatric: depressed mood; negative symptoms.

Respiratory: laryngospasm; bronchospasm; dyspnea, aspiration pneumonia; asthma; laryngeal edema.

Common side-effects of Chlorpromazine

Dizziness, sedation, dry mouth, constipation, urinary retention, blurred vision, weight gain, postural hypotension, sexual dysfunction, extrapyramidal symptoms.

Rare but serious side-effects of note of Chlorpromazine

Chlorpromazine overdose

CNS depression, hypotension, extrapyramidal symptoms, agitation, restlessness, convulsions, fever, hypothermia, hyperthermia, coma, autonomic reactions, cardiac arrhythmias.

Chlorpromazine and pregnancy

Category C: some animal studies show adverse effects at very high doses, but no controlled human studies have been done; should only be used in pregnancy if clearly needed and if benefits outweigh potential risks.

Medical Monitoring for Chlorpromzine

Because of the significant risk of weight gain and accompanying metabolic changes, the following measures should be taken prior to starting the medication, then monthly for the first 3 months of use, and then every 3 months:

  • Body Mass Index (BMI)
  • waistline circumference at umbilicus
  • blood pressure
  • fasting blood glucose
  • fasting blood lipids and cholesterol

Because of the small risk of agranulocytosis, a complete blood count should be measured prior to starting the medication, then one month after starting it, one month after every dose increase, and otherwise every 3-6 months.

To monitor for elevated prolactin, prolactin levels should be measured prior to starting the medication, and then one month after every dose increase.

Drug Interactions with Chlorpromazine

  • When combining with other CNS depressants can cause significant sedation and reduced levels of consciousness.
  • Chlorpromazine can increase blood levels of beta-blockers.
  • Chlorproamzine blood levels can be increased by beta-blockers and Paroxetine.
  • Combining with Cisapride and Sparfloxacin can result in life-threatening cardiac arrhythmias, including torsades de pointes.