RISPERDAL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for RISPERDAL (RISPERDAL).
Risperidone is a benzisoxazole atypical antipsychotic that antagonizes dopamine D2 and serotonin 5-HT2A receptors. It also blocks alpha1-adrenergic, alpha2-adrenergic, and histamine H1 receptors.
| Metabolism | Risperidone is extensively metabolized by cytochrome P450 2D6 (CYP2D6) to its active metabolite, 9-hydroxyrisperidone (paliperidone). A minor pathway involves CYP3A4 and CYP3A5. The metabolite is further metabolized via N-dealkylation and oxidative pathways. |
| Excretion | Renal: 70% (30% as unchanged drug, 40% as metabolites), Fecal/Biliary: 14% |
| Half-life | 20 hours (parent drug), 23 hours (active metabolite 9-hydroxyrisperidone). Steady state reached in 5-6 days. Extended in elderly and hepatic/renal impairment. |
| Protein binding | 90% (albumin and alpha-1-acid glycoprotein). Active metabolite 77% bound. |
| Volume of Distribution | 1-2 L/kg. Large Vd indicates extensive tissue distribution and penetration into CNS. |
| Bioavailability | Oral: 70% (with extensive first-pass metabolism). IM: 100% for immediate-release. Long-acting IM: fraction absorbed over depot injection. |
| Onset of Action | Oral: 1-2 hours (peak plasma concentration). Clinical antipsychotic effect: 1-2 weeks for initial response, full effect 4-6 weeks. IM: 30-60 minutes for peak levels. |
| Duration of Action | Oral: 24 hours (maintained with once or twice daily dosing). IM depot: 2 weeks between doses. Clinical effect duration depends on receptor occupancy. |
| Molecular Weight | 410.49 |
| Action Class | Atypical Antipsychotics |
| Brand Substitutes | Sycodone 2mg Tablet, Relivon 2mg Tablet, Restonorm 2mg Tablet, Genrest 2mg Tablet, Zisdon 2mg Tablet, Sycodone 1mg Tablet, Rion 1mg Tablet, Zepid 1mg Tablet, Rozidal 1mg Tablet, Regrace 1mg Tablet, Ristab 4mg Tablet, Rion 4mg Tablet, Rozidal 4mg Tablet, Sizomax 4mg Tablet, Respik Plus 4mg Tablet, Riszes 3mg Tablet, Rpn 3mg Tablet, Ridone 3mg Tablet, Rispee 3mg Tablet, Eritric 3mg Tablet |
2-8 mg orally once daily or divided twice daily; maximum 16 mg/day
| Dosage form | TABLET |
| Renal impairment | CrCl <30 mL/min: initial 0.5 mg twice daily, increase by 0.5 mg increments; max 3 mg/day |
| Liver impairment | Child-Pugh class A or B: initial 0.5 mg twice daily, increase by 0.5 mg increments; max 3 mg/day; Child-Pugh C: not studied |
| Pediatric use | 13-17 yr: 0.5 mg once daily, titrate by 0.5-1 mg/day at ≥24 hr intervals; target 3 mg/day; max 6 mg/day. 10-12 yr: 0.5 mg once daily, titrate by 0.5 mg/day; target 1-2.5 mg/day; max 3 mg/day |
| Geriatric use | Initial 0.5 mg twice daily; increase by 0.5 mg increments; max 3 mg/day; monitor for orthostatic hypotension and sedation |
| 1st trimester | Limited human data; animal studies show increased risk of fetal malformations. Use only if potential benefit outweighs risk. |
| 2nd trimester | Avoid unless necessary; may cause extrapyramidal symptoms and withdrawal in neonate. |
| 3rd trimester | Risk of neonatal extrapyramidal symptoms, agitation, and respiratory distress. Avoid near term. |
Clinical note
Comprehensive clinical and safety monograph for RISPERDAL (RISPERDAL).
| Placental transfer | Risperidone crosses the placenta; detected in umbilical cord blood at 50% of maternal plasma levels. |
| Breastfeeding | Risperidone is excreted into breast milk in low levels. Monitor infant for sedation, poor feeding, and extrapyramidal symptoms. Benefit of breastfeeding likely outweighs minimal risk. |
■ FDA Black Box Warning
Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Risperidone is not approved for the treatment of dementia-related psychosis.
| Serious Effects | Neuroleptic malignant syndrome, Tardive dyskinesia, QT prolongation, Stroke in elderly patients with dementia, Hyperglycemia and diabetes mellitus, Hyperprolactinemia, Orthostatic hypotension, Seizures |
Hypersensitivity to risperidone or any excipients
| Precautions | Increased mortality in elderly patients with dementia-related psychosis, Cerebrovascular adverse events (e.g., stroke, transient ischemic attack) in elderly with dementia, Neuroleptic malignant syndrome (NMS), Tardive dyskinesia, Hyperglycemia and diabetes mellitus, Weight gain, Dyslipidemia, Orthostatic hypotension and syncope, Seizures, Leukopenia, neutropenia, and agranulocytosis, QT interval prolongation, Hyperprolactinemia, Body temperature dysregulation, Dysphagia, Priapism, Thrombotic thrombocytopenic purpura (TTP) |
| Food/Dietary | Grapefruit juice may increase risperidone levels; avoid concurrent use. Risperidone can be taken with or without food. High-fat meals do not affect absorption. Weight gain is common; encourage heart-healthy diet. Alcohol may exacerbate CNS depression and orthostatic hypotension; advise avoidance. |
Loading safety data…
| Lactation Rating |
| L3 (Moderately Safe) |
| Teratogenic Risk | First trimester: Limited human data; animal studies show no evidence of teratogenicity at clinically relevant doses. Second and third trimesters: Risk of extrapyramidal symptoms and/or withdrawal symptoms in neonates if exposed during third trimester. Overall, not considered a major teratogen. |
| Fetal Monitoring | Monitor maternal blood pressure, glucose levels, weight, and psychiatric status. For fetus/neonate, monitor for extrapyramidal symptoms, sedation, and withdrawal signs after delivery. Consider ultrasound for fetal growth if prolonged use. |
| Fertility Effects | Risperidone may increase serum prolactin levels, potentially causing menstrual irregularities, anovulation, and reduced fertility. Effects are reversible upon dose reduction or discontinuation. |
| Clinical Pearls | Risperdal (risperidone) is a second-generation antipsychotic with high affinity for D2 and 5-HT2A receptors. Monitor for orthostatic hypotension during dose titration, especially in elderly. QT prolongation risk is dose-dependent; avoid with hypokalemia, hypomagnesemia, or concomitant QT-prolonging drugs. Therapeutic response for psychosis may take 2-4 weeks. For agitation, consider sublingual or IM formulations. Extrapyramidal symptoms are dose-related; more common at doses >6 mg/day. Prolactin elevation is more pronounced than with other atypical antipsychotics; monitor for galactorrhea, gynecomastia, menstrual irregularities. Weight gain and metabolic syndrome require baseline and periodic monitoring of BMI, fasting glucose, and lipids. Risk of tardive dyskinesia with long-term use. In elderly with dementia-related psychosis, increased mortality. |
| Patient Advice | Take risperidone exactly as prescribed; do not crush or chew tablets. · Avoid alcohol and grapefruit juice as they may worsen side effects. · Rise slowly from sitting or lying to prevent dizziness or fainting. · Report unusual muscle stiffness, tremors, or restlessness immediately. · Notify your doctor if you experience breast swelling, discharge, or sexual dysfunction. · Risperidone may cause drowsiness; avoid driving until you know how the drug affects you. · Do not stop abruptly; withdrawal may cause nausea, vomiting, or insomnia. · Use effective contraception if of childbearing potential; discuss pregnancy plans with your doctor. · Avoid overheating or dehydration; increased body temperature may occur. |