【藥品性質提示】 根據 2019 AGS Beers Criteria，本藥品為【潛在不適當用藥 (PIM)】，不建議用於老年人 (除非用於思覺失調、雙極症、或化療止吐)。

思覺失調症、雙極症 Treatment of schizophrenia; maintenance treatment of bipolar I disorder in adults as monotherapy or in combination with lithium or valproate

Second Generation (Atypical) Antipsychotic
Risperidone is a potent 5-HT2 antagonist with D2 antagonism. Whereas typical antipsychotics are dopamine antagonists, the additional serotonin antagonism increases efficacy for negative symptoms of schizophrenia and reduces the likelihood of EPS.

Distribution:
Plasma protein binding:
1. Risperidone 90%
2. 9-hydroxyrisperidone 77%
Metabolism:
Extensively hepatic via CYP2D6 to 9-hydroxyrisperidone (similar pharmacological activity as risperidone)
Elimination Half-life:
3-6 days due to the microsphere formulation. Risperdol Consta is an extended release microspheres formulation, composed of risperidone micro-encapsulated in polylactide-co-glycolide at a concentration of 381 mg risperidone/g of microspheres.

Hypersensitivity to risperidoneor or any component of the formulation

C

Enters breast milk/not recommended

Somnolence, fatigue, headache, fever, dystonia, anxiety, extrapyramidal symptoms, dizziness, dry mouth, constipation, weight gain, urinary incontinence, tremor, rhinitis, cough.

Administration:
Long-acting IM injection
Dosage:
1. Initial: 25 mg every 2 weeks by deep intramuscular gluteal injection; oral risperidone or another antipsychotic medication should be given with the initial injection and should be continued for 3 weeks and then discontinued.
2. Maintenance: dose may be increased to 37.5 mg or 50 mg IM at intervals of at least 4 weeks.

1. Should be stored at 2-8℃
2. If refrigeration is not available, it may be stored at <25℃ for no more than 7 days prior to administration
3. Protect from light