ADMINISTRATION ROUTES:
PO, IV, IM
ALTERNATIVE NAMES:
Largactil
ICU INDICATIONS:
- Nausea and vomiting
- Intractable hiccups
- Psychosis
PRESENTATION AND ADMINISTRATION:
IV:
50 mg/2 mL vial
Dilute required dose in 500-1000 mL of Normal saline to a concentration of no greater than 1 mg/mL and administer at 1 mg/min in adults or 0.5 mg/min in children
Dilute with Normal saline only. Do not mix with other medications in the syringe or in IV fluids. Solutions that develop a pink or yellow colouration on exposure to light should be discarded
Store at room temperature. Protect from light
PO:
10 mg, 25mg, 100 mg tablets (white or off white)
Note: Swallow whole. Do not break, crush or chew. Not suitable for nasogastric administration.
DOSAGE:
PO:
10 mg TDS
Large doses (up to 300 mg per day) may be required to treat adults with Schizophrenia; however, such doses are not appropriate in the critically ill
IV / IM:
12.5mg IV TDS
50 mg by continuous infusion over 24hrs may be used in patients with intractable hiccups
DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:
Dose in renal impairment
| GFR (ml/min) | DOSE |
|---|---|
| <10 | use a reduced dose |
| 10-20 | dose as in normal renal function |
| >20-50 | dose as in normal renal function |
Dose in renal replacement therapy
| MODALITY | DOSE |
|---|---|
| CAPD | dose as in normal renal function |
| HD | dose as in normal renal function |
| CVVHDF | dose as in normal renal function |
DOSAGE IN PAEDIATRICS:
PO:
0.5-2 mg/kg TDS
IV/IM:
0.25-1 mg/kg TDS
Note: Chlorpromazine should generally not be used in children under 6 months of age except where potentially lifesaving. It should not be used in conditions for which specific children's dosages have not been established.
CLINICAL PHARMACOLOGY:
The precise mechanism whereby the therapeutic effects of chlorpromazine are produced is not known. Chlorpromazine has actions at all levels of the central nervous system as well as on multiple organ systems. Chlorpromazine has strong antiadrenergic and weaker peripheral anticholinergic activity; ganglionic blocking action is relatively slight. It also possesses slight antihistaminic and antiserotonin activity
CONTRAINDICATIONS:
- Hypersensitivity to phenothiazines
- Depressed conscious state (unless the airway is protected)
- Hypotension or requiring vasopressor or inotropic support
WARNINGS:
The extrapyramidal symptoms which can occur with chlorpromazine may be confused with the CNS signs of an undiagnosed primary disease responsible for the vomiting
PRECAUTIONS:
General:
Given the likelihood that some patients exposed chronically to antipsychotics will develop tardive dyskinesia, it is advised that all patients in whom chronic use is contemplated be given, if possible, full information about this risk. The decision to inform patients and/or their guardians must obviously take into account the clinical circumstances and the competency of the patient to understand the information provided.
Chlorpromazine should be administered cautiously to persons with cardiovascular, liver or renal disease. There is evidence that patients with a history of hepatic encephalopathy due to cirrhosis have increased sensitivity to the CNS effects of chlorpromazine (i.e. impaired cerebration and abnormal slowing of the EEG).
Because of its CNS depressant effect, chlorpromazine should be used with caution in patients with chronic respiratory disorders such as severe asthma, emphysema, and acute respiratory infections, particularly in children (1-12 years of age)
Laboratory Tests:
No tests in addition to routine ICU tests are indicated
Drug/Laboratory Test Interactions:
Chlorpromazine may cause false positive urinary pregnancy tests
Pregnancy:
Safety for the use of chlorpromazine during pregnancy has not been established. Reproductive studies in rodents have demonstrated potential for embryotoxicity, increased neonatal mortality, and nursing transfer of the drug. Tests in the offspring of the drug-treated rodents demonstrate decreased performance. The possibility of permanent neurological damage cannot be excluded
Nursing Mothers:
There is evidence that chlorpromazine is excreted in the breast milk of nursing mothers. Because of the potential for serious adverse reactions in nursing infants from chlorpromazine, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother
Paediatric Use:
Chlorpromazine should generally not be used in children under 6 months of age except where potentially lifesaving. It should not be used in conditions for which specific children's dosages have not been established
IMPORTANT DRUG INTERACTIONS IN ICU:
Chlorpromazine prolongs and intensifies the action of CNS depressants. It may also diminish the effect of oral anticoagulants.
Phenothiazines can produce alpha-adrenergic blockade.
Chlorpromazine may lower the convulsive threshold; dosage adjustments of anticonvulsants may be necessary. Potentiation of anticonvulsant effects does not occur. However, it has been reported that chlorpromazine may interfere with the metabolism of phenytoin and thus precipitate phenytoin toxicity.
Concomitant administration with propranolol results in increased plasma levels of both drugs
ADVERSE REACTIONS:
Body as a whole:
Neuroleptic malignant syndrome
Central nervous system:
Drowsiness, seizures, dystonias, motor restlessness, pseudo-parkinsonism, and tardive dyskinesia
Cardiovascular system:
Hypotension, tachycardia, non-specific T wave changes
Gastrointestinal system:
Jaundice, nausea, constipation, dry mouth
Haematological system:
Agranulocytosis, eosinophilia, leukopaenia, haemolytic anaemia, aplastic anaemia, thrombocytopenic purpura, pancytopaenia