Converting Oral Risperidone 6 mg to UZEDY (Subcutaneous Risperidone)
For a patient stabilized on oral risperidone 6 mg daily, initiate UZEDY at 90 mg subcutaneously once monthly, which is the appropriate dose for patients taking oral risperidone doses greater than 5 mg/day. 1, 2
Dosing Algorithm Based on Oral Risperidone
The conversion follows a structured approach based on the prior oral dose:
- Oral risperidone ≤3 mg/day → UZEDY 25 mg monthly 1
- Oral risperidone >3 to ≤5 mg/day → UZEDY 37.5 mg monthly 1
- Oral risperidone >5 mg/day → UZEDY 50 mg monthly 1
However, for UZEDY (TV-46000) specifically, the dosing differs from older risperidone long-acting formulations. Based on clinical trial data, patients on 6 mg oral risperidone should receive UZEDY 90 mg monthly or 180 mg every 2 months, as these doses demonstrated significant efficacy in relapse prevention. 2
Key Advantages of UZEDY Over Other Formulations
UZEDY does not require oral supplementation or loading doses, which distinguishes it from older risperidone long-acting injections. 3, 2 This represents a significant practical advantage, as the patient can transition directly to the subcutaneous injection without continuing oral risperidone.
Administration Details
- Route: Subcutaneous injection (not intramuscular) 3, 2
- Frequency options: Either once monthly or once every 2 months 2
- Needle considerations: Smaller needle size compared to intramuscular formulations 4
- Storage: Follow manufacturer guidelines for proper storage 4
Monitoring Requirements During Transition
Extrapyramidal Symptoms (EPS)
Monitor for EPS, though risperidone typically causes less than first-generation antipsychotics. 5 The risk increases with doses exceeding 6 mg/24 hours. 5 If the patient was on anticholinergic medications for EPS management, continue these during the transition. 6
Cardiovascular Monitoring
QTc monitoring is prudent if the patient has cardiac risk factors or if doses are in the higher range. 7 Risperidone can cause orthostatic hypotension, particularly during dose transitions. 5, 6
Injection Site Reactions
Injection site nodules occur in approximately 7% of patients receiving UZEDY, which is more common than with placebo (3%). 2 These are generally mild and self-limiting.
Metabolic Parameters
Monitor weight, as weight gain occurs in 4-6% of patients on UZEDY. 2 This is consistent with other risperidone formulations' metabolic effects. 5
Common Pitfalls to Avoid
Do not use conversion ratios designed for intramuscular risperidone long-acting injection when prescribing UZEDY, as the pharmacokinetics differ substantially. 3, 4 UZEDY uses novel copolymer-based drug delivery technology that changes the dosing paradigm. 2
Do not prescribe oral risperidone supplementation alongside UZEDY initiation, as this formulation achieves therapeutic levels without oral overlap. 3 This contrasts with older formulations that required 3 weeks of oral supplementation.
Avoid underdosing: Clinical trial data showed that patients receiving lower doses (25-37.5 mg) had increased relapse tendency and decreased serum metabolite concentrations. 1 For a patient on 6 mg oral, the full 90 mg monthly dose is appropriate.
Efficacy Data
UZEDY once monthly prolonged time to relapse by 5-fold compared to placebo (hazard ratio 0.200, p<0.0001), while the every-2-month dosing prolonged it by 2.7-fold (hazard ratio 0.375, p<0.0001). 2 This demonstrates robust efficacy for relapse prevention in schizophrenia.
Special Population Considerations
In elderly patients, maximum daily oral risperidone should not exceed 5 mg, and lower conversion ratios should be used with careful titration. 6, 7 However, UZEDY clinical trials primarily enrolled adults with mean age 49 years, so extrapolation to elderly populations requires clinical judgment. 2