Largactil (Chlorpromazine)

Chlorpromazine acts on dopamine and other neurotransmitter pathways to treat a range of psychiatric and gastrointestinal conditions.

• Schizophrenia: reduces hallucinations, delusions and thought disorder.
• Acute psychotic disorders: alleviates severe agitation and psychotic symptoms.
• Manic episodes of bipolar disorder: stabilises mood and diminishes manic energy.
• Severe nausea and vomiting: controls refractory emesis when other agents fail.
• Preoperative sedation: provides calming and anti‑emetic effects before surgery.

• Chlorpromazine blocks dopamine D2 receptors, diminishing dopaminergic neurotransmission that underlies psychosis. It also antagonises histamine H1, muscarinic, alpha‑adrenergic and serotonergic receptors, contributing to its sedative, anti‑emetic, and anticholinergic properties while influencing vascular tone and gastrointestinal motility.

Adverse reactions can vary from mild to life‑threatening and should be monitored during therapy.

Common Side Effects

• Sedation: drowsiness or fatigue.
• Dry mouth: reduced salivary flow.
• Constipation: slowed gastrointestinal transit.
• Blurred vision: due to anticholinergic activity.
• Weight gain: increased appetite.
• Orthostatic hypotension: dizziness on standing.

Serious or Rare Side Effects

• Neuroleptic malignant syndrome: high fever, muscle rigidity, autonomic instability.
• Tardive dyskinesia: involuntary, repetitive movements.
• Agranulocytosis: severe reduction in white blood cells.
• Severe hypotension: marked drop in blood pressure.
• Seizures: especially in predisposed individuals.

Chlorpromazine requires careful assessment before and during treatment.

• Cardiac monitoring: patients with pre‑existing heart disease should be observed for arrhythmias.
• CNS depression: avoid alcohol and other sedatives that may enhance drowsiness.
• Anticholinergic load: monitor for urinary retention, glaucoma or constipation.
• Metabolic effects: watch for weight gain and lipid changes.
• Pregnancy and lactation: use only if benefits outweigh potential risks.
• Store at ambient temperature: keep below 25 °C, in the original container, protected from moisture and light.

Chlorpromazine can interact with several drug classes, altering efficacy or safety.

Major Interactions (Avoid)

• Monoamine oxidase inhibitors (MAOIs): risk of hypertensive crisis.
• CNS depressants (e.g., benzodiazepines, opioids): additive sedation and respiratory depression.
• Anticholinergic agents: heightened anticholinergic side effects.

Moderate Interactions (Monitor Closely)

• Antihypertensives: may potentiate hypotensive effects.
• Lithium: increased risk of neurotoxicity.
• Antidiabetic drugs: may mask hypoglycemia symptoms.