Risperidone (Risperdal): Uses, Dosage, Side Effects, and What to Expect

Risperidone (brand name: Risperdal, Risperdal Consta) is a atypical antipsychotic (second-generation). Risperidone is a potent antagonist at both dopamine D2 and serotonin 5-HT2A receptors. At lower doses (1-3 mg), the 5-HT2A/D2 ratio favors an 'atypical' profile with lower EPS risk. At higher doses (>6 mg), D2 blockade becomes dominant and the side effect profile resembles typical antipsychotics with increased EPS and prolactin elevation. Risperidone is the most potent prolactin-elevating atypical antipsychotic, which has significant clinical implications especially in children and adolescents.

• Schizophrenia
• Bipolar I Disorder (acute manic/mixed episodes)
• Irritability associated with Autism Spectrum Disorder (ages 5-16)

Common off-label uses:

• Tourette's disorder
• PTSD
• Behavioral disturbance in dementia (controversial — black box warning)
• OCD augmentation
• Aggression in intellectual disability

Schizophrenia: 2-4 mg/day (start 1-2 mg, target 4-6 mg). Bipolar mania: 2-6 mg/day. Autism irritability: start 0.25-0.5 mg/day, target 0.5-3 mg based on weight. Long-acting injection (Consta): 25-50 mg every 2 weeks. Take with or without food.

Antipsychotic effects begin within 1-2 weeks. Full response for schizophrenia: 4-6 weeks. Antimanic effects within days to 1 week.

• Weight gain (moderate — less than olanzapine, more than aripiprazole)
• Sedation
• Elevated prolactin (highest of atypicals — can cause breast enlargement, galactorrhea, menstrual irregularities, sexual dysfunction, and long-term bone density loss)
• Extrapyramidal symptoms (dose-dependent)
• Orthostatic hypotension
• Increased appetite

• Hyperprolactinemia (persistent elevation causes gynecomastia, amenorrhea, osteoporosis, and is particularly concerning in children)
• Tardive dyskinesia (risk increases with duration)
• Neuroleptic malignant syndrome
• Metabolic syndrome
• Increased mortality in elderly with dementia (black box warning)
• Cerebrovascular events in elderly

CYP2D6 substrate — fluoxetine, paroxetine increase levels. Carbamazepine decreases levels significantly. Active metabolite paliperidone (9-hydroxyrisperidone) is renally cleared. Additive sedation with CNS depressants.

Category C. Third-trimester exposure may cause extrapyramidal symptoms and withdrawal in newborns. Use only if benefits clearly outweigh risks.

Taper gradually over 1-2 weeks to avoid rebound psychosis and cholinergic/dopaminergic supersensitivity symptoms. Withdrawal dyskinesia possible.