Can Ingrezza Cause Leg Muscle Pain?
Ingrezza (valbenazine) is not documented to cause leg muscle pain as a recognized adverse effect in clinical trials or FDA approval studies. The available evidence from phase 2 and phase 3 trials does not identify muscle pain, myalgia, or leg pain as reported side effects of this medication 1, 2.
Evidence from Clinical Trials
Valbenazine was FDA-approved in 2017 specifically for treating tardive dyskinesia, becoming the first medication with this indication 3, 4.
The pivotal KINECT 3 trial, which included 225 participants over 6 weeks, demonstrated that valbenazine was "generally well tolerated" with adverse event profiles consistent with previous studies, but muscle pain was not reported among the documented side effects 2.
Clinical research on valbenazine has focused on its efficacy in reducing abnormal involuntary movements, with the medication showing significant improvement in tardive dyskinesia symptoms at 80 mg/day dosing 1, 2.
Mechanism and Safety Profile
Valbenazine works as a vesicular monoamine transporter 2 (VMAT2) inhibitor, which decreases abnormal movements by reducing dopamine release at nerve terminals 4.
The medication has advantages including once-daily dosing and rapid onset of effect within 2 weeks of treatment initiation 4.
While valbenazine shares some mechanistic similarities with tetrabenazine, it has demonstrated a better short-term side effect profile in clinical trials 1.
Important Caveats
The longest clinical trials evaluating valbenazine were only 6 weeks in duration, meaning long-term side effects may not yet be fully characterized 2.
Naturalistic observational trials are needed to carefully investigate putative long-term side effects that may emerge with chronic administration 5.
If leg muscle pain develops while taking Ingrezza, alternative causes should be investigated, as this symptom is not established as a drug-related adverse effect based on current evidence 1, 2.