Generic Name

Chlorpromazine

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Classification

FDA Approved Indications

• Schizophrenia
• Manic-depressive illness (short-term adjunct)
• Intractable hiccups
• Nausea and vomiting (preoperative antiemetic)
• Tic disorders

Mechanism of Action

Chlorpromazine blocks dopamine D2 receptors in the brain, reducing dopaminergic transmission, which alleviates psychotic symptoms.

Dosage and Administration

Adult: Typically 25-50 mg two to three times daily; dosage may be adjusted based on clinical response and tolerability.

Pediatric: Use is limited; dosing varies and should be determined by a specialist.

Geriatric: Start at lower doses (e.g., 25 mg daily) due to increased sensitivity and risk of adverse effects; titrate cautiously.

Renal Impairment: Adjust dose based on clinical response and tolerability; no specific guidelines, monitor closely.

Hepatic Impairment: Use with caution; no specific dose adjustments, start low and go slow.

Pharmacokinetics

Absorption: Well absorbed from the gastrointestinal tract

Distribution: Widely distributed in body tissues; crosses blood-brain barrier and placenta

Metabolism: Hepatic metabolism via hydroxylation and conjugation; CYP450 involvement varies

Excretion: Primarily via renal route as metabolites

Half Life: About 16-30 hours, variable depending on individual factors and chronicity of use

Contraindications

• Comcurrent use with CNS depressants or alcohol
• Comatose states
• Bone marrow suppression

Precautions

• Use cautiously in elderly patients (due to risk of falls, sedation, and neuroleptic malignant syndrome)
• History of Parkinson’s disease
• Seizure disorders
• Prolonged QT interval

Adverse Reactions - Common

• Sedation (Very common)
• Dizziness (Common)
• Dry mouth (Common)
• Extrapyramidal symptoms (restlessness, tremors) (Common)

Adverse Reactions - Serious

• Neuroleptic malignant syndrome (fever, rigidity, altered mental status) (Rare)
• QT prolongation and arrhythmias (Rare)
• Agranulocytosis (Rare)
• Seizures (Rare)

Drug-Drug Interactions

• CNS depressants (additive sedation)
• Anticholinergics (potential for increased side effects)
• Other QT-prolonging agents (risk of arrhythmias)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed.
• Report any signs of movement disorders, fever, muscle rigidity, or unusual blood work to a healthcare provider.
• Avoid alcohol and CNS depressants.
• Be aware of the potential for sedation and avoid driving until sedation levels are known.

Special Considerations

Black Box Warnings:

• Increased mortality in elderly patients with dementia-related psychosis

Genetic Factors: Dosing may need adjustment based on CYP450 enzyme activity.

Lab Test Interference: May cause false positives in urine drug screens.

Overdose Management

Signs/Symptoms: Extrapyramidal symptoms, hypotension, somnolence, seizures, respiratory depression, coma.

Treatment: Supportive care, gastric lavage if early, activated charcoal, IV fluids, and monitoring of vital signs. No specific antidote.

Storage and Handling

Storage: Store at room temperature away from light and moisture.

Stability: Stable under recommended conditions for shelf life specified in packaging.