- 10 mg tab x 100
- 25 mg tab x 100
- 100 mg tab x 100
- 25 mg/ 5 mL x 100 mL
Phenothiazine major tranquiliser antipsychotic: dopamine inhibitor that
- alleviates anxiety, tension, agitation
- potentiates CNS depression of analgesics, narcotics, sedatives
- Antiemetic
- Tends to elevate prolactin levels
- Alpha-adrenergic blockade
- Raise serum glucose and cholesterol
Dosage
- Starting: 25 mg bd-tid
- Maintenance: 25-100 mg tid
- Irritant injection, should be given by deep intramuscular injection
- 25-50 mg deep IMI q6-8hr prn x 24 hours
Monitor BP: Transient postural hypotension
Acute Functional Psychosis
- Schizophrenia
- Mania
- Psychotic depression
Long-term treatment of schizophrenia
- Short-term treatment of agitation, behavioural disturbance in patients with delirium or dementia
- Short-term treatment in agitation or severe depression
- Severe behavioural disturbance in mental retardation or autism
- Palliation to enhance effects of analgesics and control nausea and vomiting
- Control of intractable hiccough
Contraindication
- CNS depression
- Circulatory collapse
- Hypersensitivity to phenothiazines – Excipients such as sodium metabisulfite and sodium sulphite can cause allergic reactions
- Bone marrow depression
- Pheochromocytoma
- Active liver disease
Precaution (avoid)
- Epilepsy: neuroleptics lower the seizure threshold
- Parkinson Disease: phenothiazines block post-synaptic dopamine transmission
- Hypoparathyroidism: severe dystonic reaction of untreated
- Myasthenia gravis: because of its strong antimuscarinic effect
- Prostatic hypertrophy: anticholinergic effect
- Disturbs thermoregulation
- Tardive dyskinesia: long-term and often irreversible (total cumulative dose)
- Liver dysfunction
- Retinopathy
- Reye’s syndrome
- Renal disease
- Glaucoma
- Elderly
Adverse effects
- Impair memory and alertness
- Agranulocytosis: 1:1300 – 1:500,000
- Photosensitivity
- Postural Hypotension
- QT Interval
- Dry mouth. Constipation
- Urinary retention
- Blurred vision
- Weight gain
- Raised ANA
- SIADH
- Cholestatic jaundice
- Venous thromboembolism
- Hyperglycaemia
- Neuroleptic malignant syndrome
- Pregnancy Category: C
- Excreted in breast milk
Interactions
- TCAs decrease clearance of chlorpromazine
- CYP1A2 inhibitors: ciprofloxacin, fluvoxamine
- Other CNS depressants
- Oral absorption is erratic and considerable first-pass metabolism (Peak plasma levels 1-4 hours after oral administration)
- Peak plasma levels 15-30 minutes after intramuscular injection
- Widely distributed and crosses blood brain barrier achieving higher concentrations in brain than plasma
- Highly protein bound
- Complex metabolism including hepatic demethylation, N-oxidation, sulphoxidation, deamination, and conjugation such that 43-65% is excreted in the urine in 24 hours but <1% unchanged.
- Supportive treatment of overdose: Nad (not Ad)
- Hypothermia: Shivering is a sign of waning effects of drug
- Severe extrapyramidal effects: Benztropine 1-2 mg (0.2-0.25 mg children) IM +/- increments
- Therapeutic serum level: 100-3– mg/mL / Toxicity: 750 ng/mL / Not routinely monitored
Pharmaceutical sponsor: Sanofi-Aventis 21/10/91, updated 28/8/12
