ADMINISTRATION ROUTES:
PO, IM
ALTERNATIVE NAMES:
Ridal, Risperidal
ICU INDICATIONS:
- Agitation and delirium
- Psychosis
PRESENTATION AND ADMINISTRATION:
IM:
Long-acting Depot ONLY (not for use in ICU)
PO:
Tablets:
Ridal 0.5mg (red), 1mg (white), 2mg (orange), 3mg (yellow), 4mg (green)
Risperidal 0.5mg (brownish / red), 1mg (white), 2mg (orange), 3mg (yellow), 4mg (green)
Oral Disintegrating Tablets:
Risperdal Quicklet 0.5mg (light coral), 1mg (light coral), 2mg (coral)
Oral Solution:
Risperdal Solution 1 mg/mL
DOSAGE:
PO:
0.5 - 1 mg BD
Increase to max 8 mg BD
DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:
Dose in renal impairment
| GFR (ml/min) | DOSE |
|---|---|
| <10 | 0.5 mg BD increasing to 1 - 2 mg BD |
| 10-20 | 0.5 mg BD increasing to 1 - 2 mg BD |
| >20-50 | 0.5 mg BD increasing to 1 - 2 mg BD |
Dose in renal replacement therapy
| MODALITY | DOSE |
|---|---|
| CAPD | 0.5 mg BD increasing to 1 - 2 mg BD |
| HD | 0.5 mg BD increasing to 1 - 2 mg BD |
| CVVHDF | 0.5 mg BD increasing to 1 - 2 mg BD |
DOSAGE IN PAEDIATRICS:
0.02 mg/kg BD
Increase to 0.15 mg/kg BD
CLINICAL PHARMACOLOGY:
Risperidone is a benzisoxazole derivative. It is a selective monoaminergic antagonist with a high affinity for serotoninergic 5-HT2 and dopaminergic D2 receptors. Risperidone binds also to alpha1-adrenergic receptors and, with lower affinity, to H1-histamine and alpha2-adrenergic receptors. It has no cholinergic action. It may improve the positive symptoms of schizophrenia with less depression of motor activity and induction of catalepsy as seen with classical neuroleptics. Extrapyramidal side effects are reduced by balance central serotonin and dopamine antagonism.
CONTRAINDICATIONS:
- Sensitivity to risperidone
WARNINGS:
Increased risk of deaths in patients with dementia
Elderly patients with dementia-related psychosis treated with atypical antipsychotic drugs are at an increased risk of death compared to placebo.
Hyperglycaemia and Diabetes Mellitus
Hyperglycaemia, in some cases extreme and associated with ketoacidosis or hyperosmolar coma or death, has been reported in patients treated with atypical antipsychotics including risperidone.
Neuroleptic Malignant Syndrome (NMS)
A potentially fatal symptom complex sometimes referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with administration of antipsychotic drugs, including risperidone.
Tardive Dyskinesia
A syndrome of potentially irreversible, involuntary, dyskinetic movements may develop in patients treated with antipsychotic drugs.
PRECAUTIONS:
General:
Risperidone may induce hypotension.
Classical neuroleptics are known to lower the seizure threshold. Caution is recommended when treating patients with epilepsy.
Laboratory Tests:
No tests additional to routine ICU tests are indicated
Drug/Laboratory Test Interactions:
None reported
IMPORTANT DRUG INTERACTIONS IN ICU:
Given the primary CNS effects of risperidone, it should be used with caution in combination with other centrally-acting medicines.
Carbamazepine has been shown to decrease the plasma levels of the active antipsychotic fraction of risperidone. On discontinuation of carbamazepine the dosage of risperidone should be re-evaluated and, if necessary, decreased.
ADVERSE REACTIONS:
Cardiovascular System:
Hypotension, tachycardia, hypertension
Digestive System:
Dry mouth, constipation, dyspepsia, vomiting
Nervous System:
Somnolence, dizziness, tremor, hypertonia
Haematological System:
Decreased neutrophil count, decreased platelet count