What is Thorazine (chlorpromazine) used for?

What is Thorazine (Chlorpromazine) Used For?

Chlorpromazine is primarily used for treating schizophrenia and acute psychotic episodes, severe agitation and violent behavior in emergency settings, intractable nausea and vomiting, and persistent hiccups unresponsive to other treatments. 1

Primary Psychiatric Indications

Schizophrenia Management

• Chlorpromazine is effective for treating acute episodes and preventing relapse in schizophrenia, with a recommended therapeutic dose equivalent to 600mg per day 1
• It provides global improvement in symptoms and functioning, with patients showing significant clinical response compared to placebo 2
• However, in treatment-resistant schizophrenia (defined as failure of at least 2 adequate antipsychotic trials), clozapine should be considered as the preferred agent rather than chlorpromazine 3, 1

Acute Agitation and Behavioral Emergencies

• Chlorpromazine is recommended for management of severe agitation and violent behavior, particularly in emergency settings 1
• For acute agitation, 12.5 mg IM every 4-6 hours is effective, with similar efficacy to droperidol by 60 minutes 4
• Consider combining with lorazepam for enhanced effect in severe agitation 4

Severe Behavioral Problems in Children

• Chlorpromazine is used for severe behavioral problems in children, though careful monitoring is required due to its side effect profile 1

Non-Psychiatric Indications

Antiemetic Use

• Chlorpromazine is effective for treating intractable nausea and vomiting in various clinical scenarios 1
• It is not first-line for chemotherapy-induced nausea; use only for breakthrough symptoms after 5-HT3 antagonists fail 4
• Prochlorperazine (a related phenothiazine) is generally preferred over chlorpromazine for antiemetic purposes 4

Persistent Hiccups

• Chlorpromazine is recommended as adjunctive treatment for persistent hiccups unresponsive to other interventions 1
• If oral chlorpromazine therapy fails or long-term therapy is anticipated, consider alternative agents like metoclopramide, baclofen, or gabapentin 4

Palliative Care Applications

• Chlorpromazine is used for sedation in management of refractory symptoms at end of life 1
• For terminal restlessness, 12.5 mg IV every 4-12 hours or 25 mg PR every 4-12 hours provides effective symptom control 4
• Starting doses: 12.5mg every 4-12 hours (IV/IM) or 25-100mg every 4-12 hours (rectal) 1

Critical Safety Considerations and Monitoring

Cardiovascular Risks

• Chlorpromazine can cause QTc prolongation, potentially resulting in torsades de pointes, requiring ECG monitoring 1, 5
• Avoid co-administration with other QT-prolonging medications, as this significantly increases arrhythmia risk 1, 4
• Chlorpromazine is more likely to cause hypotension than some other antipsychotics (NNH 7), with significant orthostatic hypotension and dizziness (NNH 11) 1, 2

Extrapyramidal Symptoms

• Extrapyramidal symptoms occur more frequently with chlorpromazine than with atypical antipsychotics 4
• Monitor for dystonic reactions, akathisia, and pseudo-parkinsonism 4
• When compared to medium-dose chlorpromazine (401-800 mg/day), significantly more people experience extrapyramidal symptoms than with low-dose (≤400 mg/day) 6

Special Population Considerations

• Start with lowest effective doses (12.5-25 mg) for elderly and debilitated patients 4
• Elderly patients have increased risk of falls due to orthostatic hypotension and sedation, and higher sensitivity to anticholinergic effects and extrapyramidal symptoms 4
• Patients with hepatic encephalopathy due to cirrhosis have increased sensitivity to CNS effects of chlorpromazine 7

Other Important Adverse Effects

• Chlorpromazine is clearly sedating (NNH 5) 2
• It causes considerable weight gain (NNH 2) 2
• Regular assessment of cardiovascular status, extrapyramidal symptoms, and metabolic parameters is essential 1, 5
• Given chronic use, patients should be informed about the risk of tardive dyskinesia 7

Dosing Principles

• The optimal dosing range is 12.5-400 mg/day, with most modern practice favoring the lower end of this spectrum 4
• The minimum effective dose for schizophrenia treatment is equivalent to 600mg per day 1
• The usual effective parenteral dose ranges from 37.5-150mg/day 1
• For parenteral administration in acute agitation: 12.5mg every 4-12 hours IV/IM or 3-5mg/hour IV 1