Atypical Antipsychotic — Autism Spectrum Disorder / Schizophrenia / Tic Disorders Pregnancy: Use with caution — neonatal withdrawal/EPS if used near term; avoid unless clearly necessary

Risperidone (Paediatric)

Brand names: Risperdal, Risperidone Orodispersible

Adult dose

Dose: Schizophrenia: 2 mg on day 1, 4 mg on day 2, then 4–6 mg/day; Mania: 2–6 mg/day

Route: Oral

Frequency: Once or twice daily

Max: 16 mg/day

Adult reference — see paediatric dose section

Paediatric dose

Dose: ASD behavioural symptoms: initial 0.25 mg/day (<20 kg) or 0.5 mg/day (≥20 kg); increase by 0.25–0.5 mg every 2 weeks mg/day (fixed initiation, not strictly per-kg)/kg

Route: Oral (liquid 1 mg/mL, orodispersible or standard tablets)

Frequency: Once daily or divided twice daily

Max: ASD: 1.5 mg/day (<20 kg); 2.5 mg/day (20–45 kg); 3.5 mg/day (>45 kg); Schizophrenia (≥13 years): up to 6 mg/day

BNFc: licensed for irritability/aggression in autism (≥5 years); for schizophrenia in adolescents (≥13 years); for mania (≥10 years). Liquid formulation (1 mg/mL) enables accurate low-dose titration in young/small children. EPS (extrapyramidal side effects) less than haloperidol but still significant — monitor. Metabolic monitoring mandatory.

Dose adjustments

Renal

Start at 0.25–0.5 mg twice daily; increase by 0.5 mg BD every week — renal impairment slows elimination of active moiety

Hepatic

Same low starting dose as renal impairment; titrate slowly

Paediatric weight-based calculator

Patient weight (kg)

Clinical pearls

ASD irritability: RUPP (Research Units on Paediatric Psychopharmacology) trial established risperidone significantly reduces irritability, aggression, and self-injurious behaviour in children with ASD — first FDA-approved treatment for this indication; aripiprazole also approved
Metabolic monitoring: mandatory at baseline and every 3 months — weight, BMI, fasting glucose, fasting lipids; metabolic syndrome risk is substantial in children; dietary and lifestyle counselling alongside
Hyperprolactinaemia: can cause pubertal delays, galactorrhoea, gynacomastia in boys — measure prolactin if suspected; aripiprazole is prolactin-sparing alternative
Tardive dyskinesia risk: increases with cumulative dose and duration — lowest effective dose for shortest necessary duration; AIMS (Abnormal Involuntary Movement Scale) every 6 months
NMS: fever + rigidity + altered consciousness + autonomic instability — stop immediately; ITU if severe; bromocriptine/dantrolene used in severe cases

Contraindications

QT prolongation
Dementia-related psychosis in elderly (increased mortality — not applicable to paediatrics but note)
Hypersensitivity to risperidone

Side effects

Weight gain (significant — metabolic monitoring essential)
Extrapyramidal symptoms (EPS): dystonia, akathisia, tardive dyskinesia (prolonged use)
Hyperprolactinaemia (galactorrhoea, amenorrhoea, gynaecomastia)
Sedation
QTc prolongation
Metabolic syndrome (dyslipidaemia, hyperglycaemia)
Orthostatic hypotension
Neuroleptic malignant syndrome (rare)

Interactions

QT-prolonging drugs — additive risk
CYP2D6 inhibitors (fluoxetine, paroxetine) — increase risperidone levels significantly
Carbamazepine — reduces risperidone levels (CYP3A4 induction)
CNS depressants — additive sedation
Antihypertensives — additive hypotension

Monitoring

Weight and BMI (monthly × 3 months, then 3-monthly)
Fasting glucose and lipids (baseline, 3 months, then annually)
Prolactin (if symptoms suggest hyperprolactinaemia)
ECG (QTc)
AIMS assessment every 6 months
Blood pressure (orthostatic)

Reference: BNF for Children; NICE NG11 (ASD); RUPP Trial NEJM 2002; MHRA Antipsychotic Metabolic Monitoring Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways