Chlorpromazine

Chlorpromazine (中文:[[ ]]) is a typical antipsychotic medication. It is used to treat psychotic disorders such as

• schizophrenia
• Bipolar disorder
• Severe anxiety
• Attention deficit hyperactivity disorder
• Hiccups that do not improve following other measures

Pronunciation

Chlorpromazine 50mg

Drug Names

Generic Name 藥名	HA Code 藥物代碼	Classification藥物分類
Chlorpromazine Tablet 25 mg	CHLO44	P1S1S3
Chlorpromazine Tablet 50 mg	CHLO46	P1S1S3

Mechanism of Action

Chlorpromazine and other typical antipsychotics are primarily blockers of D2 dopamine receptor. The presumed effectiveness of antipsychotic drugs relied on their ability to block dopamine receptors. This assumption arose from the dopamine hypothesis that maintains that both schizophrenia and bipolar disorder are a result of excessive dopamine activity. In addition, chlorpromazine also acts as an antagonist (blocking agent) on different postsynaptic and presynaptic receptors:

• Dopamine receptors (subtypes D1, D2, D3 and D4), which account for its antipsychotic properties
• Serotonin receptors (5-HT2, 5-HT6 and 5-HT7), with anxiolytic, antidepressant, and anti-aggressive properties
• Histamine receptors (H1 receptors) accounting for sedation, antiemetic effect
• α1- and α2-adrenergic receptors accounting for lowering of blood pressure, reflex tachycardia, vertigo, sedation, hypersalivation and incontinence as well as sexual dysfunction
• M1 and M2 muscarinic acetylcholine receptors causing anticholinergic symptoms such as dry mouth, blurred vision, constipation, difficulty to urinate, sinus tachycardia, and loss of memory.

Dosage

Indication	Dose
Acute and chronic schizophrenia Reduce acute mania in bipolar disorder Control severely violent behaviour Adjunctive management of severe anxiety	By mouth ADULT: Initially 25 mg 3 times a day, adjusted according to response Or initially 75 mg once daily, taken at night, adjusted according to response Maintenance 75 – 300 mg daily ELDERLY or debilitated patients: A third to half adult dose By rectum ADULT: 25 – 50 mg 3 – 4 times a day