Chlorpromazine is used in the following conditions:

• Schizophrenia and other psychotic disorders (particularly paranoid types), mania, and hypomania.
• In cases of anxiety with psychomotor agitation, excitement, violent, or dangerously impulsive behavior. It is often used as an adjunct for short-term management in such conditions.
• Persistent (intractable) hiccups.
• Nausea and vomiting associated with terminal illness (when other treatments are ineffective or unavailable).
• Childhood schizophrenia and autism.
• Use medicines only as advised by a registered physician

Chlorpromazine functions as an antagonist (blocking agent) at multiple postsynaptic receptors. It primarily blocks dopaminergic receptors (D1, D2, D3, and D4), contributing to its antipsychotic effects on both positive and negative symptoms. It also acts on serotonergic receptors (5-HT1 and 5-HT2), providing anxiolytic, antidepressant, and anti-aggressive effects, while helping reduce extrapyramidal symptoms—though it may cause weight gain, hypotension, sedation, and sexual dysfunction. Additionally, it blocks histaminergic (H1) receptors, leading to sedation, antiemetic effects, dizziness, reduced blood pressure, and weight gain. Its action on alpha1/alpha2 receptors produces antisympathetic effects such as lowered blood pressure, reflex tachycardia, dizziness, sedation, hypersalivation, incontinence, and sexual dysfunction, and may also reduce pseudoparkinsonism. Chlorpromazine also affects muscarinic (cholinergic) M1/M2 receptors, resulting in anticholinergic effects such as dry mouth, blurred vision, constipation, urinary retention, sinus tachycardia, ECG changes, and memory impairment. These anticholinergic effects may help lessen extrapyramidal side effects. Furthermore, it weakly inhibits presynaptic dopamine reuptake, which may contribute to mild antidepressant and antiparkinsonian effects. This mechanism may also influence psychomotor agitation and, in rare cases, worsen psychosis.

Adults: In general medicine and psychiatry-

• Oral route: average daily dose of 30 to 75 mg (mild cases) or 75 to 100 mg (more severe cases) in divided doses. It is occasionally necessary to give a higher dosage which, when increased gradually, can reach 900 mg or more per day in some psychiatric patients.
• Once the optimum dosage has been reached, it is maintained as long as necessary for the control of symptoms during the critical phase of the illness. Eventually, however, it should be gradually reduced so that the patient can be maintained on the lowest effective dosage.

Adults: In surgery and anesthesia-

• To potentiate hypnotics, analgesics and anesthetics and as an antiemetic.
• Oral route: doses of 25 to 50 mg are administered 2 to 3 hours before anesthesia and every 4 to 6 hours after surgery.

Children:

• Usual single dose: 1/4 mg per pound (1/2 mg/kg) by oral route. This dose can be repeated every 4 to 6 hours as necessary. The normal daily dose is 40 mg for a child of 5 years (40 pounds), 75 mg for children of 5 to 12 years (50 to 100 pounds) except in psychiatric patients where dosages can be progressively elevated above these levels.
• In surgery and anesthesia, doses of 1/4 mg per pound, by the same method recommended for adults.

Interactions leading to reduced chlorpromazine levels: Food, alcohol, and benztropine may decrease the absorption of chlorpromazine. Antacids can delay its absorption. Lithium and long-term use of barbiturates may increase the clearance of chlorpromazine.

Interactions leading to increased chlorpromazine levels: Tricyclic antidepressants may reduce the clearance of chlorpromazine, resulting in higher serum concentrations. Concomitant use with CYP1A2 inhibitors—especially strong inhibitors such as ciprofloxacin and fluvoxamine, or moderate inhibitors like oral contraceptives and vemurafenib—can raise chlorpromazine plasma levels. As a result, patients may experience dose-related adverse effects.

Severe central nervous system depression or coma caused by alcohol, barbiturates, analgesics, or other CNS depressants. Also contraindicated in patients with blood disorders, severe liver disease, or known hypersensitivity to phenothiazines.

Drowsiness is common at the start of therapy but usually lessens with dose reduction or continued use. Orthostatic hypotension may occur, especially with higher doses. Dystonic and extrapyramidal reactions can develop during prolonged treatment or at high doses, but these effects may be managed by reducing the dose or using antiparkinsonian medication.

Less commonly reported effects include nasal congestion, blurred vision, dry mouth, sedation, nausea, constipation, changes in libido, gynecomastia, weight gain, pigmentation of the skin and cornea, photosensitivity, blood dyscrasias, leukopenia, eosinophilia, and ECG changes.

Rarely, prolongation of the QT interval has been observed. There have also been isolated reports of sudden death, possibly of cardiac origin, as well as unexplained sudden death in patients receiving phenothiazine antipsychotics.

Cholestatic jaundice and liver injury (mainly cholestatic or mixed type) have been reported infrequently.

Very rare cases of systemic lupus erythematosus have been noted; in some cases, antinuclear antibodies may be present without clinical symptoms.

Priapism has also been reported very rarely in patients receiving chlorpromazine.

Pregnancy Category C. Animal studies following oral administration have demonstrated reproductive toxicity, including dose-dependent embryo-fetotoxicity (increased resorption and fetal death). A higher rate of malformations was observed in mice, but only at doses associated with maternal toxicity. Data on reproductive toxicity via parenteral administration are insufficient. In humans, the teratogenic potential of chlorpromazine has not been conclusively established, and studies with related phenothiazines have produced inconsistent findings. Chlorpromazine is excreted into breast milk in variable amounts; therefore, its use in breastfeeding mothers is not recommended unless the anticipated benefit outweighs potential risks.

Chlorpromazine may enhance the effects of other phenothiazines and CNS depressants. At the initiation of therapy, the usual doses of barbiturates, analgesics, narcotics, or antihistamines should be reduced. Patients should avoid alcohol consumption during treatment.

Phenothiazines may prolong the QT interval, particularly in the presence of bradycardia, hypokalemia, or congenital/acquired QT prolongation.

Caution is advised in patients with arteriosclerosis, cardiovascular disease, or conditions where a sudden drop in blood pressure may be harmful. If hypotension occurs and a vasopressor is required, norepinephrine is preferred over epinephrine, as epinephrine may worsen hypotension.

Due to its anticholinergic effects, chlorpromazine should be used cautiously in patients with glaucoma or prostatic hypertrophy.

During long-term therapy, especially with high doses, regular monitoring of blood counts and liver function is recommended.

Drowsiness may occur at the beginning of treatment; therefore, patients should avoid driving or engaging in activities requiring mental alertness until this effect diminishes.

Phenothiazines may lower the seizure threshold and trigger epileptic seizures; hence, patients should continue their usual anticonvulsant therapy at the same dose.

Because of its antiemetic action, chlorpromazine may mask symptoms of increased intracranial pressure or intestinal obstruction.

False-positive or false-negative pregnancy test results have been reported in patients receiving phenothiazines.

Elderly: Older patients are more sensitive to the adverse effects of chlorpromazine. The initial dose should be approximately half of the usual adult dose, with gradual adjustments under regular supervision.

Anti-emetic drugs, Phenothiazine drugs, Phenothiazine related drugs

Store below 30°C, protected from light and moisture. Keep out of reach of children.