Chlorpromazine: Difference between revisions

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[[Category: Drugs]][[Category: typical antipsychotic ]]
[[Category: Drugs]][[Category: Typical Antipsychotic ]]
'''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==
[[:Category: Antipsychotic Drug | '''Antipsychotic Drug''']]
===Chlorpromazine 50mg===
[[File:Chlorpromazine 50mg.mp3]]


==Drug Names==
'''Drug class: [[:Category: Typical Antipsychotic  | Typical Antipsychotic]]
{| class="wikitable"
 
!Generic Name 藥名
'''Chlorpromazine (LARGACTIL)'''（中文：[[氯丙嗪]]）
!HA Code 藥物代碼
==Common Strengths of Chlorpromazine Tablet==
!Classification藥物分類
Chlorpromazine are available in the following strengths:
|-
*Tablets: 25 mg, 50 mg, 100 mg
|Chlorpromazine Tablet 25 mg
 
|CHLO44
==Drug Trade Names of Chlorpromazine Tablet==
|P1S1S3
Largactil
|-
 
|Chlorpromazine Tablet 50 mg
==Drug Usage==
|CHLO46
Treatment of schizophrenia and other psychotic disorders
|P1S1S3
|}


==Mechanism of Action==
==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.
Chlorpromazine acts s an antagonist on various postsynaptic receptors:
In addition, chlorpromazine also acts as an antagonist (blocking agent) on different postsynaptic and presynaptic receptors:
*Blocks dopamine D<sub>1</sub>, D<sub>2</sub>, D<sub>3</sub>, and D<sub>4</sub> receptors
*Dopamine receptors (subtypes D1, D2, D3 and D4), which account for its antipsychotic properties
*Blocks serotonin 5-HT<sub>1</sub> and 5-HT<sub>2</sub> receptors
*Serotonin receptors (5-HT2, 5-HT6 and 5-HT7), with anxiolytic, antidepressant, and anti-aggressive properties
*Blocks histamine H<sub>1</sub> receptors
*Histamine receptors (H1 receptors) accounting for sedation, antiemetic effect
*Blocks alpha-1 and alpha-2 adrenergic receptors
*α1- and α2-adrenergic receptors accounting for lowering of blood pressure, reflex tachycardia, vertigo, sedation, hypersalivation and incontinence as well as sexual dysfunction
*Blocks muscarinic acetylcholine receptors
*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.
 
==Route of Administration==
Oral
 
==Dosages==
For schizophrenia in adults:
*Initial: 25 - 50 mg orally 3 times daily
*Maintenance: 200 - 400 mg daily in divided dose
*Maximum: 1000 mg daily


==Dosage==
==Side Effects==
{| class="wikitable"
{| class="wikitable"
!style="text-align: left"| Indication
!style="text-align: left"| Frequency
!style="text-align: left"| Dose
!Adverse reactions
|-
|-
!style="text-align: left"|  
| rowspan="10" | '''Common
*Acute and chronic schizophrenia
| Drowsiness and sedation
*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
|-
|-
!style="text-align: left"| Intractable hiccup
| Dizziness
|By ''mouth
ADULT: 25 – 50 mg 3-4 times a day
|-
|-
!style="text-align: left"| Nausea and vomiting of terminal illness
| Dry mouth
|By ''mouth
|-
ADULT: 10 – 25 mg every 4-6 hours
| Blurred vision
CHILD 1-5 years: 500 micrograms/kg every 4-6 hours; max. 40 mg per day
|-
CHILD 6-11 years: 500 micrograms/kg every 4-6 hours; max. 75 mg per day
| Constipation
CHILD 12-17 years: 10 – 25 mg every 4-6 hours
|-
By ''rectum
| Weight gain
ADULT: 100 mg every 6-8 hours
|-
|}
| Increased appetite
 
|-
Chlorpromazine is given orally as the hydrochloride and the embonate.
| Nausea
 
|-
For both salts, the doses are expressed as the hydrochloride. Chlorpromazine embonate 144 mg is equivalent to 100 mg of chlorpromazine hydrochloride.
| Difficulty urinating
 
|-
If the oral route is not suitable, it may be given rectally as suppositories containing 100 mg of chlorpromazine base
| Skin sensitivity to sunlight
 
|-
==Side Effects==
| rowspan="9" | '''Serious
Chlorpromazine generally produces less central depression than the benzodiazepines, and tolerance to its initial sedative effects develops quickly in most patients. Tardive dyskinesia (involuntary, repetitive body movements) and akathisia (a feeling of inner restlessness and inability to stay still) are less commonly seen with chlorpromazine than they are with high potency typical antipsychotics such as haloperidol or trifluoperazine.
| a. Exterapyramidal symptoms (movement disorders):
 
*Muscle stiffness or spasms
Possible side effects include:
*Tremors
{| class = "wikitable"
*Restlessness (akathisia)
!style="text-align: left"| It has antimuscarinic properties and may cause the following side effects such as
*Parkinson-like symptoms
|
*Dry mouth
*Constipation
*Difficulty to urinate
*Blurred vision
*Mydriasis
*Tachycardia
*ECG changes (particularly Q- and T-wave abnormalities)
*Orthostatic hypotension is common
|-
|-
!style="text-align: left"| Other adverse effects include
| b. Tardive dyskinesia (potentially irreversible involuntary movements of face and tongue)
|
*Delirium
*Agitation
*sedation
*Insomnia
*Nightmares
*Glaucoma
*Inhibition of ejaculation
*Impotence
|-
|-
!style="text-align: left"| Hypersensitivity reactions include
| c. Neuroleptic malignant syndrome (fever, muscle rigidity, altered mental state)
|
*Urticaria
*Exfoliative dermatitis
*Prolonged therapy may lead to deposition of pigment, producing a bluish-purple discoloration in the skin
*Corneal and lens opacities
*Photosensitivity reaction
|-
|-
!style="text-align: left"| Haematological disorders
| d. Low white blood cell count (agranulocytosis)
|
*Haemolytic anaemia
*Thrombocytopenic purpura
*Most cases of agranulocytosis occurred within 4 to 10 weeks starting treatment
|-
|-
!style="text-align: left"| Extrapyramidal dysfunction include
| e. Seizures
|
*Acute dystonia
*A parkinsonism-like syndrome
*Tardive dyskinesia
*Neuroleptic malignant syndrome
|-
|-
!style="text-align: left"| Altered endocrine and metabolic functions
| f. QT prolongation leading to dangerous heart arrhythmias
|
*Developed amenorrhoea, galactorrhoea and gynaecomastia due to hyperprolactinaemia
*Weight gain
*Hyperglycaemia
*Body temperature regulation is impaired and may result in hypo- or hyperthermia depending on environment.
|}
 
==Pharmacokinetics==
{|class="wikitable"
!style="text-align: left"| Oral bioavailability
|Chlorpromazine is readily, although sometimes erratically absorbed after oral doses.
|-
|-
!style="text-align: left"| Onset of action
| g. Difficulty regulating body temperature
|Peak plasma concentrations occur about 2 to 4 hours after ingestion.
|-
|-
!style="text-align: left"| Metabolism
| h. Hormonal changes:
|It is subject to considerable first-pass metabolism in the gut wall and is also extensively metabolized in the liver.
*Increased prolactin levels
*Breast enlargement or milk production
*Menstrual changes
|-
|-
!style="text-align: left"| Elimination half-life
| i. Sever low blood pressure
|
It is excreted in the urine and faeces.
Owing to the first-pass effect, plasma concentrations after oral doses are much lower than those after intramuscular doses.
The plasma half-life of chlorpromazine occurs about 30 hours.
|}
|}
==Pharmacokinetics==
*Absorption: Well absorbed orally, but undergoes extensive first-pass metabolism
*Metabolism: Extensively metabolized in the liver
*Elimination: Mainly in urine as metabolites
*Onset: 30 - 60 minutes after oral administration
*Duration: 4 - 6 hours (single dose), up to 24 hours (multiple doses)
==Drug Precautions==
'''Pregnancy
Use only if potential benefit outweighs risk. May cause extrapyramidal symptoms in newborns if used in 3rd trimester.
'''Breastfeeding
Use caution. Chlorpromazine is excreted in breast milk.
'''Children and Elderly
*Children: Use caution. Safety and efficacy not established in children < 1 year old.
*Elderly: Start at lower doses and titrate slowly due to increased sensitivity to side effects.
'''Renal Impairment
Use with caution. No specific dosage adjustments required.
'''Monitoring Requirements
*Blood pressure
*Body temperature
*Complete blood count
*Liver function tests
*Eye examinations
*ECG in patients at risk of QT prolongation
'''Drug Interactions
*Increased CNS depression with alcohol, barbiturates, opioids
*Increased risk of arrhythmias with drug that prolong QT interval
*Decreased effectiveness of levodopa
*Increased risk of extrapyramidal symptoms with metoclopramide
==FAQ==
'''How Should I Take the Tablet?
Take with or without food.
'''What Should I Avoid While Taking?
Avoid alcohol, driving or operating machinerty until you know how it affect you. Avoid excessive sun exposure.
'''What Happens if I Miss a Dose?
Take the missed dose as soon as you remember unless it is almost time for your next dose. Do not double doses.

Latest revision as of 04:02, 29 July 2024


Antipsychotic Drug

Drug class: Typical Antipsychotic

Chlorpromazine (LARGACTIL)（中文：氯丙嗪）

Common Strengths of Chlorpromazine Tablet[edit]

Chlorpromazine are available in the following strengths:

  • Tablets: 25 mg, 50 mg, 100 mg

Drug Trade Names of Chlorpromazine Tablet[edit]

Largactil

Drug Usage[edit]

Treatment of schizophrenia and other psychotic disorders

Mechanism of Action[edit]

Chlorpromazine acts s an antagonist on various postsynaptic receptors:

  • Blocks dopamine D1, D2, D3, and D4 receptors
  • Blocks serotonin 5-HT1 and 5-HT2 receptors
  • Blocks histamine H1 receptors
  • Blocks alpha-1 and alpha-2 adrenergic receptors
  • Blocks muscarinic acetylcholine receptors

Route of Administration[edit]

Oral

Dosages[edit]

For schizophrenia in adults:

  • Initial: 25 - 50 mg orally 3 times daily
  • Maintenance: 200 - 400 mg daily in divided dose
  • Maximum: 1000 mg daily

Side Effects[edit]

Frequency Adverse reactions
Common Drowsiness and sedation
Dizziness
Dry mouth
Blurred vision
Constipation
Weight gain
Increased appetite
Nausea
Difficulty urinating
Skin sensitivity to sunlight
Serious a. Exterapyramidal symptoms (movement disorders):
  • Muscle stiffness or spasms
  • Tremors
  • Restlessness (akathisia)
  • Parkinson-like symptoms
b. Tardive dyskinesia (potentially irreversible involuntary movements of face and tongue)
c. Neuroleptic malignant syndrome (fever, muscle rigidity, altered mental state)
d. Low white blood cell count (agranulocytosis)
e. Seizures
f. QT prolongation leading to dangerous heart arrhythmias
g. Difficulty regulating body temperature
h. Hormonal changes:
  • Increased prolactin levels
  • Breast enlargement or milk production
  • Menstrual changes
i. Sever low blood pressure

Pharmacokinetics[edit]

  • Absorption: Well absorbed orally, but undergoes extensive first-pass metabolism
  • Metabolism: Extensively metabolized in the liver
  • Elimination: Mainly in urine as metabolites
  • Onset: 30 - 60 minutes after oral administration
  • Duration: 4 - 6 hours (single dose), up to 24 hours (multiple doses)

Drug Precautions[edit]

Pregnancy

Use only if potential benefit outweighs risk. May cause extrapyramidal symptoms in newborns if used in 3rd trimester.

Breastfeeding

Use caution. Chlorpromazine is excreted in breast milk.

Children and Elderly

  • Children: Use caution. Safety and efficacy not established in children < 1 year old.
  • Elderly: Start at lower doses and titrate slowly due to increased sensitivity to side effects.

Renal Impairment

Use with caution. No specific dosage adjustments required.

Monitoring Requirements

  • Blood pressure
  • Body temperature
  • Complete blood count
  • Liver function tests
  • Eye examinations
  • ECG in patients at risk of QT prolongation

Drug Interactions

  • Increased CNS depression with alcohol, barbiturates, opioids
  • Increased risk of arrhythmias with drug that prolong QT interval
  • Decreased effectiveness of levodopa
  • Increased risk of extrapyramidal symptoms with metoclopramide

FAQ[edit]

How Should I Take the Tablet?

Take with or without food.

What Should I Avoid While Taking?

Avoid alcohol, driving or operating machinerty until you know how it affect you. Avoid excessive sun exposure.

What Happens if I Miss a Dose?

Take the missed dose as soon as you remember unless it is almost time for your next dose. Do not double doses.

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