Chlorpromazine Oral: Dosing, Duration, and Precautions

Therapeutic action

Sedative antipsychotic.

Indications

Due to the numerous and potentially severe adverse effects of chlorpromazine, patients should be kept under close surveillance.

• Acute or chronic psychosis, in the event of intolerance or treatment failure with other antipsychotics. Preferably use haloperidol for this indication.

Forms and strengths

• 25 mg and 100 mg tablets.

Dose

• Adult: 25 to 50 mg once daily in the evening for one week. Increase gradually to 50 mg in the morning and 100 mg in the evening; if insufficient, administer 100 mg 3 times daily.
• Reduce the dose by half in older patients.
• Use the lowest effective dose, especially in prolonged treatment.

Duration

Discontinue treatment gradually over 4 weeks. If signs of relapse occur, increase the dose then decrease it more gradually.

• Acute psychosis: at least 3 months.
• Chronic psychosis: at least one year.

Contra-indications, adverse effects, precautions

• Do not administer to patients with cardiac disorders, dementia, closed-angle glaucoma, prostate disorders, Parkinson's disease, or a history of neuroleptic malignant syndrome.
• Administer with caution and carefully monitor use in older patients and in patients with hypokalaemia, hypotension, renal or hepatic impairment, or a history of seizures.
• May cause drowsiness, dyskinesia, extrapyramidal symptoms, weight gain, orthostatic hypotension, hyperprolactinaemia, and anticholinergic effects including dry mouth, blurred vision, urinary retention, constipation, and tachycardia.
• May also cause hyperglycaemia, photosensitivity, impaired thermoregulation, agranulocytosis, and neuroleptic malignant syndrome, which requires immediate discontinuation.
• In case of extrapyramidal symptoms, try reducing the dose of chlorpromazine or add biperiden or trihexyphenidyl if symptoms are severe.
• Avoid or monitor combinations with CNS depressants, drugs with anticholinergic effects, antidiabetics, lithium, antihypertensive drugs, and drugs that prolong the QT interval.
• Avoid alcohol during treatment.
• Pregnancy: re-evaluate whether treatment is still necessary. If continued, use the lowest effective dose and observe the neonate if the mother was under treatment in the 3rd trimester. If treatment starts during pregnancy, preferably use haloperidol.
• Breast-feeding: if absolutely necessary, use the lowest effective dose.