StatPearls covers risperidone as an atypical antipsychotic used for schizophrenia, bipolar disorder, and irritability in autism, among other indications. I can’t reproduce StatPearls verbatim, but here’s a concise, clinically useful summary of the typical points you’d see in that entry.
What risperidone is
- Class: Atypical antipsychotic (dopamine D2 and serotonin 5-HT2A receptor antagonist; also blocks other receptors such as alpha-1 and H1 to a lesser extent).
- Available forms: Oral tablets and orally disintegrating tablets; long-acting injectable (Risperdal Consta) administered every 2 weeks.
Common indications
- Schizophrenia (adults and adolescents)
- Bipolar I disorder (manic or mixed episodes, often as an adjunct to mood stabilizers)
- Irritability associated with autism spectrum disorder in children/adolescents (FDA-approved in children typically aged 5–16)
Key pharmacology
- Metabolism: Hepatic metabolism with active metabolite 9-hydroxyrisperidone (paliperidone is the active metabolite of risperidone, but paliperidone is used as a separate drug).
- Pharmacokinetics: Oral bioavailability relatively good but subject to first-pass metabolism; long-acting injectable offers dosing every 2 weeks.
Dosing is highly indication- and age-specific
- Adults with schizophrenia: starting around 1 mg twice daily (2 mg/day total) and titrating to a typical range of 4–6 mg/day; some patients may go to up to 8 mg/day in practice, but higher doses increase risk of side effects.
- Mania/bipolar: often 2–3 mg/day, titrating based on response and tolerability.
- Autism-related irritability (children/adolescents): pediatric dosing is lower and titrated; typical total daily doses are in the range of 0.5–3 mg/day (divided dosing), with adjustments by weight and response.
- Long-acting injectable (Risperdal Consta): 25–50 mg by deep intramuscular injection every 2 weeks (dose may be adjusted in some cases).
Important adverse effects and safety
- Movement disorders: Extrapyramidal symptoms (EPS) including dystonia, akathisia, and parkinsonism; risk increases with higher doses.
- Hyperprolactinemia: Galactorrhea, menstrual irregularities, breast tenderness, gynecomastia; can affect bone health with long-term exposure.
- Metabolic effects: Modest weight gain; changes in lipids and glucose risk are lower than with some other antipsychotics but still notable—monitor weight, fasting glucose, and lipids.
- Sedation and orthostatic hypotension: Common early effects; may improve with dose adjustment.
- QT interval: Possible QT prolongation, particularly with higher doses or in patients with other risk factors.
- Elderly patients with dementia-related psychosis: Increased mortality risk; not recommended for this population.
- Others: anticholinergic effects, sexual side effects, and rare agranulocytosis (very uncommon but monitor as with other antipsychotics).
Monitoring and safety
- Baseline and periodic: weight, height/BMI, waist circumference; fasting glucose or HbA1c; fasting lipids; blood pressure; prolactin if symptoms suggest hyperprolactinemia.
- EPS screening: watch for muscle stiffness, tremor, restlessness (use AIMS if indicated).
- Pregnancy/lactation: Risperidone is categorized cautiously; discuss risks if pregnancy is planned or suspected. It can be excreted in breast milk.
- Drug interactions:
- CYP2D6 inhibitors (e.g., fluoxetine, paroxetine) can raise risperidone levels.
- CYP2D6 inducers can lower levels.
- Additive CNS depressant effects with alcohol or sedatives.
- QT-prolonging drugs increase risk of QT interval prolongation.
- Discontinuation: Do not stop abruptly; taper to minimize withdrawal symptoms and potential relapse.
Counseling tips
- Take with or without food; consistency helps with absorption.
- Be aware of potential drowsiness or dizziness when starting.
- Report signs of EPS, significant weight gain, changes in menstrual cycle, galactorrhea, or severe sedation.
- Avoid abrupt changes in dosing; follow prescriber instructions for switching from oral to injectable or between formulations if applicable.
If you want, I can:
- Break this down by indication (schizophrenia vs mania vs autism-related irritability) with typical starting doses and targets.
- Create a quick one-page reference with dosing ranges and key adverse effects tailored to adults or to pediatric patients.
- Provide a section-by-section outline mirroring StatPearls (indications, dosing, mechanism, pharmacokinetics, adverse effects, interactions, monitoring, special populations, pregnancy/lactation, and patient education).
Tell me your target use (clinical reference for an adult, pediatrics, pharmacy student, or patient handout) and I’ll tailor the summary.