From the Research
The equivalent dose of Risperdal Consta (long-acting injectable risperidone) for someone taking 3.5 mg of oral risperidone daily would be approximately 25 mg injected every two weeks. This conversion is based on pharmacokinetic studies showing that 25 mg of Risperdal Consta every two weeks provides similar average plasma concentrations to 2-4 mg of oral risperidone daily 1. When transitioning from oral to injectable form, patients should continue their oral risperidone for 3 weeks after the first injection to maintain therapeutic levels, as the long-acting formulation takes time to reach steady state. The injectable form offers advantages of improved adherence and more stable blood levels compared to daily oral dosing, but requires regular clinic visits for administration by a healthcare professional. Risperdal Consta is typically available in doses of 12.5 mg, 25 mg, 37.5 mg, and 50 mg, so the 25 mg dose would be the closest match. The most recent and highest quality study supports the use of long-acting risperidone in patients with schizophrenia, including those with stable symptoms, and demonstrates its effectiveness and tolerability 2, 1. Key points to consider when prescribing Risperdal Consta include:
- Starting with a dose of 25 mg every two weeks
- Continuing oral risperidone for 3 weeks after the first injection
- Monitoring patients for potential side effects, such as extrapyramidal symptoms and injection site pain
- Regular clinic visits for administration and monitoring.