Thorazine (chlorpromazine hydrochloride) is a first-generation typical antipsychotic medication with a well-established clinical profile for managing severe psychiatric and neurological disorders. As a phenothiazine derivative, it functions primarily as a dopamine D2 receptor antagonist, exerting potent antipsychotic, antiemetic, and sedative effects. Its use spans over six decades, supported by extensive clinical evidence and a comprehensive understanding of its pharmacodynamic and pharmacokinetic properties. Thorazine remains a cornerstone in acute agitation management, treatment-resistant psychosis, and certain off-label applications where newer agents may be insufficient or contraindicated.

Features

• Active ingredient: Chlorpromazine hydrochloride
• Available formulations: Oral tablets (10 mg, 25 mg, 50 mg, 100 mg, 200 mg), syrup (25 mg/5 mL), and injectable solution (25 mg/mL)
• Half-life: Approximately 30 hours
• Metabolism: Hepatic, primarily via CYP2D6
• Excretion: Renal and fecal
• Pregnancy category: C
• DEA schedule: Not controlled

Benefits

• Rapid reduction of psychotic symptoms, including hallucinations, delusions, and disorganized thinking
• Effective management of acute agitation and violent behavior in emergency psychiatric settings
• Proven efficacy in treatment-resistant cases where atypical antipsychotics have failed
• Useful as an antiemetic for severe nausea and vomiting unresponsive to conventional treatments
• Cost-effective option compared to many newer antipsychotic agents
• Established long-term safety profile with decades of clinical use and post-marketing surveillance

Common use

Thorazine is indicated for the management of manifestations of psychotic disorders, including schizophrenia and schizoaffective disorder. It is also used in the treatment of acute intermittent porphyria, severe behavioral problems in children (1–12 years) marked by combativeness and explosive hyperexcitable behavior, and as an adjunct in the treatment of tetanus. Off-label uses include management of intractable hiccups, severe anxiety, and as an antiemetic in palliative care settings. Its use in dementia-related psychosis is not recommended due to increased mortality risk in elderly patients with dementia-related psychosis.

Dosage and direction

Dosage must be individualized based on diagnosis, severity of symptoms, and patient response. For psychosis in adults: initial dose 25–50 mg orally two to three times daily, increasing gradually over 1–2 weeks to 400–800 mg daily in divided doses. Maximum daily dose should not exceed 2000 mg. For acute agitation: 25–50 mg IM, may repeat in 1–4 hours if necessary. Switch to oral therapy as soon as feasible. For children aged 6 months–12 years: 0.25 mg/kg orally every 4–6 hours or 0.5 mg/kg IM every 6–8 hours. Maximum IM dose 40 mg/day for children under 5 years or 75 mg/day for children 5–12 years. Always titrate gradually and use the lowest effective dose.

Precautions

Monitor for extrapyramidal symptoms (EPS), tardive dyskinesia, and neuroleptic malignant syndrome (NMS). Regular assessment of CBC, liver function, and ocular exams recommended with prolonged use. Use with caution in patients with cardiovascular disease, hepatic impairment, or seizure disorders. May impair mental/physical abilities required for hazardous tasks. Avoid abrupt discontinuation after long-term use. Orthostatic hypotension may occur, particularly with parenteral administration. Photosensitivity reactions possible; advise sun protection. Hyperprolactinemia may occur with chronic use.

Contraindications

Hypersensitivity to chlorpromazine or other phenothiazines. Comatose states, significant CNS depression due to alcohol, barbiturates, opioids, or other agents. Bone marrow suppression. Pre-existing severe cardiovascular disease. Concomitant use with large doses of hypnotics. Should not be used in children under 6 months except where potentially lifesaving.

Possible side effect

Common: Sedation, dizziness, orthostatic hypotension, dry mouth, blurred vision, constipation, weight gain.
Serious: Extrapyramidal symptoms (dystonia, akathisia, parkinsonism), tardive dyskinesia, neuroleptic malignant syndrome, agranulocytosis, seizures, jaundice, pigmentary retinopathy with prolonged high-dose therapy. Cardiovascular effects including QT prolongation, tachycardia, and ECG changes. Endocrine effects including galactorrhea, amenorrhea, and gynecomastia.

Drug interaction

Potentiates CNS depression with alcohol, barbiturates, opioids, and other sedatives. May potentiate effects of antihypertensives. Concurrent use with anticholinergics may increase risk of hyperthermia. CYP2D6 inhibitors (e.g., fluoxetine, paroxetine) may increase chlorpromazine levels. May antagonize effects of levodopa and direct-acting sympathomimetics. Use with QT-prolonging agents may increase arrhythmia risk.

Missed dose

If a dose is missed, administer as soon as remembered unless it is nearly time for the next dose. Do not double doses. Maintain regular dosing schedule. Abrupt discontinuation after long-term use should be avoided; taper gradually under medical supervision.

Overdose

Symptoms include severe CNS depression, hypotension, tachycardia, extrapyramidal symptoms, agitation, restlessness, convulsions, cardiac arrhythmias, and coma. Treatment is supportive and symptomatic. Gastric lavage may be considered if presented early. Maintain airway and administer IV fluids for hypotension. Avoid epinephrine. ECG monitoring required. Extrapyramidal symptoms may be treated with diphenhydramine or benztropine.

Storage

Store at controlled room temperature (20–25°C/68–77°F). Protect from light. Keep in tightly closed container. Do not freeze oral liquid formulation. Keep all medications out of reach of children and pets.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Thorazine is a prescription medication that should be used only under the supervision of a qualified healthcare professional. Individual response to medication may vary. Always consult with a healthcare provider for diagnosis and treatment recommendations. Never adjust dosage or discontinue medication without medical supervision.

Reviews

“Thorazine remains an essential tool in our psychiatric emergency department for rapid control of acute agitation. While newer agents have advantages, nothing matches its rapid onset and potency in severe cases.” - Board Certified Psychiatrist, 15 years experience

“In treatment-resistant schizophrenia, we occasionally revert to Thorazine when atypical antipsychotics fail. The response can be remarkable, though monitoring for EPS is crucial.” - Psychiatric Pharmacist Specialist

“While sedating, Thorazine’s antiemetic properties make it valuable in palliative care when other antiemetics fail. The cost-effectiveness is an additional benefit in resource-limited settings.” - Palliative Medicine Physician