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Atypical Antipsychotic (D2/5-HT2A Antagonist) Pregnancy: Caution — neonatal EPS/withdrawal; if essential, lowest effective dose

Risperidone

Brand names: Risperdal, Risperdal Consta (LAI)

Adult dose

Dose: Schizophrenia: 2 mg OD–BD on day 1, 4 mg OD–BD on day 2, then 4–6 mg/day. Elderly: max 2 mg/day. LAI (Risperdal Consta): 25–50 mg IM every 2 weeks.
Route: Oral or IM (LAI)
Frequency: OD–BD oral; every 2 weeks (LAI)
Max: 16 mg/day oral; 50 mg/2 weeks LAI
More EPS than quetiapine/aripiprazole, especially at doses >6 mg. Significantly elevates prolactin (galactorrhoea, menstrual irregularities, sexual dysfunction). Available as liquid solution for those with swallowing difficulties.

Paediatric dose

Dose: 0.01 mg/kg
Route: Oral
Frequency: BD
Max: 3 mg/day (children <50 kg); 6 mg/day (children ≥50 kg)
Concentration: 1 mg/mL solution mg/ml
Autism spectrum disorder (irritability/aggression): ≥5 years and ≥20 kg: 0.25 mg OD, titrate to 0.5–1 mg/day. Schizophrenia ≥15 years: adult-like dosing starting 1 mg/day. MHRA: not for conduct disorders as sole treatment.

Dose adjustments

Renal

Reduce to half normal dose in renal impairment

Hepatic

Reduce to half normal dose in hepatic impairment

Paediatric weight-based calculator

Autism spectrum disorder (irritability/aggression): ≥5 years and ≥20 kg: 0.25 mg OD, titrate to 0.5–1 mg/day. Schizophrenia ≥15 years: adult-like dosing starting 1 mg/day. MHRA: not for conduct disorders as sole treatment.

Clinical pearls

  • Prolactin: persistently elevated — screen for galactorrhoea, menstrual irregularities, sexual dysfunction at each review
  • Long-term bone density: hyperprolactinaemia causes low bone density — DEXA at baseline and every 2–3 years on long-term therapy
  • LAI (Risperdal Consta): cover with oral risperidone for first 3 weeks after starting injection (delayed therapeutic levels)
  • Children with ASD: 0.25 mg/day starting dose — highly effective for irritability/self-injury, but metabolic monitoring essential

Contraindications

  • QT prolongation or risk factors

Side effects

  • EPS (dose-dependent — akathisia, parkinsonism, tardive dyskinesia)
  • Hyperprolactinaemia (galactorrhoea, amenorrhoea, sexual dysfunction, osteoporosis long-term)
  • Weight gain
  • Metabolic syndrome
  • Sedation
  • Orthostatic hypotension
  • QT prolongation

Interactions

  • Antihypertensives — additive hypotension
  • QT-prolonging drugs — additive risk
  • Carbamazepine — reduces risperidone levels by 50% (increase dose)
  • CYP2D6 inhibitors (fluoxetine, paroxetine) — increase risperidone levels

Monitoring

  • Weight and BMI
  • Blood glucose and lipids
  • Prolactin level (baseline, 6 months, then annually)
  • ECG (QTc)
  • EPS assessment
  • DEXA (long-term)

Reference: BNFc; BNF; NICE NG117; BNF for Children; BAP Antipsychotic Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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