Concept About Chlorpromazine – This book covers the entire syllabus of “Pharmacology” prescribed by BNMC- for diploma in nursing science & midwifery students. We tried to accommodate the latest information and topics. This book is an examination setup according to the teachers’ lectures and examination questions.
At the end of the book, previous questions are given. We hope in touch with the book students’ knowledge will be upgraded and flourish. The unique way of presentation may make your reading of the book a pleasurable experience.
Concept About Chlorpromazine
Pharmacological action of Chlorpromazine.
❖ Non-specific dopamine receptor (D1 and D2) antagonist.
❖Most effective in schizophrenia than other drugs.
❖ Strongly sedative
Theory-1:
Anti-psychotic action: Due to post-synaptic inhibition of dopamine receptor in the mesolimbic system
Theory-2
Extra-pyramidal syndrome effect Due to blockage of postsynaptic receptors in the nigrostriatal pathway (neuralgic cause of Parkinsonism).
Theory-3
Endocrine effect; Due to blockage of dopamine receptors in tubero-infundibular dopamine pathway (increase prolactine secretion).
Pharmacological action of Chlorpromazine
CNS effects
1. Anti-psychotic effect:
➤ Apathy
➤ Reduced initiative
➤ Aggressive tendencies reduced.
2. Extra-pyramidal effect (block of nigrostriatal dopamine receptor)
➤ Parkinson like symptoms.
➤ Tardive dyskinesia
3. Effects on CTZ: inhibition of CTZ produces
➤ Anti-emetic action
➤ Anti-hiccup action.
4. Effects on hypothalamus:
➤ Hypotension
➤ Hypothermia
5. Endocrine effects: (increase prolactine secretion) –
➤ Amenorrhoea
➤ Galactorrhoea
➤ Cynaecomastia
On ANS
1. Postural hypotension due to a-1 adrenergic blocking action leading to fall of B.P.
2. Anti-cholinergic & anti-serotonine like action.
On CVS
1. Postural/orthostatic hypotension due to a blockage
2. Reflex tachycardia.
3. Anti-arrhythmic effect.
On Endocrine system
Chlorpromazine depresses hypothalamus and so decreases the release of GH, ACTH, oxytocin and Gonadotropin hormones and increase release of prolactin. As a result no ovulation take place due to lack of preovulatory LH surge, but signs and symptoms like pregnancy (e.g. Amenorhoea & lactation) develops called “Pseudopregnancy”.
Other Effects
1. Analgesia.
2. Antihistaminic effect: sedation.
3. Local anaesthetic effect
4. Diuretic effect: due to decrease ADH secretion
Indication of Chlorpromazine
1. Major psychosis: Treatment of the Schizophrenia and depression with agitation (dose: 100-1000 mg/day).
2. Minor disorder: Anxiety, neurosis, manic depression, alcoholism, drug dependence.
3. As anti-emetic and anti-hiccup agent.
4. Delirious condition of children.
5. Pre-anaesthetic medication with narcotic analgesics.
6. Pre-eclampsia, eclampsia & in tetanus for muscle relaxation.
7. Management of withdrawal symptoms caused by the barbiturate and alcohol.
8. Amphetamine poisoning.
9. Pruritus (anti-histaminic action).
10. Huntington’s chorea.
Contraindication of Chlorpromazine
1. Growing children.
2. Hepatic diseases
3. Comatose patient
4. Poisoning by CNS depressants
5. Bone marrow depression.
Adverse effects of Chlorpromazine
A. On ANS
➤ Dryness of mouth
➤ Blurring of vision
➤ Cycloplegia
➤ Constipation
➤ Difficulty in micturation
➤ Impotency
➤ Failure of ejaculation
B. On CVS
➤ Postural hypotension
➤ Syncope
➤ Reflex tachycardia
C. On CNS
➤ Mental depression
➤Tremor, dystonia
➤ Drowsiness, lathery
➤ Extra-pyramidal effects (common in children)
D. On Endocrine system
➤ Increase prolactin secretion:
- Amenorrhoea
- Galactorrhoea
- Gynaecomastia
➤ Infertility Antihistaminic action: Sedation Idiosyncratic & hypersensitivity
➤ Cholestatic jaundice
➤ Skin rashes
➤ Leukopenia
➤ Agranulocytosis
➤ Photosensitivity
Treatment of Schizophrenia
Anti-psychotic drugs:
➤ Tab. Chlorpromazine (largactile) 100 mg 1+1+1
➤ Tab. Perkinil (5 mg) | To prevent extra-pyramidal side 1+0+1 effects of largactile.
➤ Inj. Fluphenazine decanote (25-100 mg): 1 amp. IM every 1-4 weeks (according to severity), (for long time prophylactic and to prevent relapse).