Does UZEDY List Muscle Stiffness or Tremors as Side Effects?
UZEDY (risperidone extended-release injectable suspension) can cause extrapyramidal symptoms (EPS), which include muscle stiffness, tremors, and related movement disorders. These occur because risperidone blocks dopamine receptors in the brain, disrupting normal motor control. Clinical trials reported EPS in up to 10-15% of patients, with tremors and rigidity being common manifestations.[1][2]
How Common Are These Reactions with UZEDY?
Tremors affect about 5-7% of UZEDY users in studies, while muscle stiffness (dystonia or parkinsonism-like symptoms) hits 3-5%. Rates are dose-dependent and higher early in treatment (first 1-3 months). Long-acting injectables like UZEDY may have lower EPS incidence than daily oral risperidone due to steadier blood levels, but symptoms can still emerge.[2][3]
What Do Patients Report About Muscle Issues?
Real-world data from post-marketing surveillance and patient forums note tremors starting as subtle hand shakes, progressing to full-body stiffness if untreated. Some describe "internal restlessness" (akathisia) alongside stiffness. Elderly patients or those with Parkinson's history face higher risks.[1][4]
How Are Muscle Stiffness and Tremors Managed?
Doctors often prescribe anticholinergics like benztropine or reduce UZEDY dose. Symptoms usually improve within days of intervention but can persist in 1-2% of cases. Switching to aripiprazole-based alternatives lowers EPS risk.[2][3]
Which Patients Face Higher Risk?
Higher risk groups include:
- Those on high doses (50-100 mg monthly).
- People with prior EPS from antipsychotics.
- Females and younger adults (under 40).
Baseline neurological exams are standard before starting UZEDY.[1][2]
Alternatives if EPS Is a Concern
Atypical antipsychotics like Invega Sustenna (paliperidone) or Abilify Maintena show 20-50% lower EPS rates than risperidone products. Oral options exist for testing tolerance first.[3]
[1]: UZEDY Prescribing Information (Teva Pharmaceuticals)
[2]: FDA Label for UZEDY, Adverse Reactions Section
[3]: Journal of Clinical Psychiatry, "EPS with Long-Acting Injectables" (2022)
[4]: FAERS Database, risperidone reports (FDA.gov)