From the Guidelines
Risperidone-induced somnolence (drowsiness) is likely to reverse when the medication is discontinued, although the exact timeline may vary based on individual factors. The reversal of somnolence is expected due to the medication's mechanism of action and its half-life. Risperidone causes somnolence by blocking histamine H1 receptors and certain serotonin receptors in the brain, which affects wakefulness pathways 1.
Key Points to Consider
- The medication has a half-life of about 20 hours (including its active metabolite), so it takes approximately 4-5 days to be mostly cleared from the body.
- Elderly patients or those with liver impairment may experience a longer recovery period.
- If considering stopping risperidone due to somnolence, it is crucial to consult a doctor first, as abrupt discontinuation can cause withdrawal symptoms.
- A study on the management of insomnia in children and adolescents with autism spectrum disorders found that risperidone improves sleep rates and reduces somnolence (12% vs 37%) 1. Some important factors to consider when discontinuing risperidone include:
- Gradual tapering schedule to minimize withdrawal symptoms
- Alternative medications with less sedating properties if antipsychotic treatment is still needed
- Close monitoring by a healthcare professional to adjust the treatment plan as necessary.
From the Research
Somnolence Associated with Risperidone
- The studies provide information on the incidence of somnolence as a side effect of risperidone, but do not directly address whether somnolence reverses when risperidone is discontinued 2, 3, 4, 5, 6.
- One study suggests that somnolence is a common side effect of antipsychotics, including risperidone, and that the risk of somnolence is positively correlated with dose and duration for some antipsychotics 3.
- Another study found that risperidone is effective in treating behavioral and psychological symptoms of dementia, including sleep disturbances, but does not provide information on the reversal of somnolence when the medication is discontinued 4.
- A study on risperidone medication errors in children found that somnolence/sedation was the most common symptom, but does not address the reversal of somnolence when risperidone is discontinued 5.
- A pharmacokinetic study found that concomitant use of armodafinil and risperidone may necessitate risperidone dosage adjustment, but does not provide information on the reversal of somnolence when risperidone is discontinued 6.
Reversal of Somnolence
- There is no direct evidence in the provided studies to suggest that somnolence associated with risperidone reverses when the medication is discontinued.
- However, one study suggests that allowing tolerance to develop over at least 4 weeks is reasonable before discontinuing an antipsychotic, implying that somnolence may decrease over time 3.