risperidone microspheres

General information

• Class: Long-acting injectable antipsychotic
• Common US brands: RISPERDAL CONSTA
• Typical dose range: Administration is intramuscular every 2 weeks. Dose selection is individualized to response and tolerability within labeled ranges.
• Long-acting injectable formulation available.
• Therapeutic drug monitoring not routinely recommended.
• Last reviewed: 2025-12-30

Dosing & forms

• Forms/strengths: Intramuscular injection every 2 weeks (q2wk).
• Typical range: Administration is intramuscular every 2 weeks. Dose selection is individualized to response and tolerability within labeled ranges.

Mechanism (brief)

Long-acting injectable risperidone formulation (microspheres) providing sustained dopamine D2 and serotonin 5-HT2A antagonism; used for maintenance treatment when adherence support is prioritized.

Metabolism & Half‑life

• Metabolism: CYP2D6
• Half‑life: Steady-state range 72–144 h

Therapeutic Drug Monitoring (TDM)

Recommended: No

Long‑acting injectable (LAI)

Monitoring highlights

• Weight/BMI and waist circumference; fasting lipids and glucose/HbA1c at baseline and periodically.
• Movement disorder monitoring (parkinsonism, akathisia, tardive dyskinesia).
• Prolactin-related symptoms; targeted labs when indicated.
• Blood pressure/orthostasis monitoring in older adults or antihypertensive co-use.
• ECG monitoring when baseline QTc risk is elevated or QT-prolonging co-medications are present.

Sources

• RISPERDAL CONSTA (risperidone) long-acting injection — Prescribing Information — DailyMed (2025)
• RISPERDAL (risperidone) prescribing information — DailyMed (2025)
• Long-acting injectable risperidone: efficacy and safety of the first long-acting atypical antipsychotic — American Journal of Psychiatry (2003)
• The CANMAT and ISBD Guidelines for the Management of Patients With Bipolar Disorder: 2021 Update — Bipolar Disorders (2021)