A Phase 4 interventional study of Metaxalone 640 mg Oral Tablet in Sciatica Acute and Lumbar Spinal Stenosis, sponsored by Primus Pharmaceuticals. Recruiting at 24 sites in United States. Open to participants aged 18 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-14.
Sponsored by Primus Pharmaceuticals · Phase 4, Interventional, and Treatment
The goal of this clinical trial is to learn if a modification to metaxalone 640 mg can reduce low back and leg pain. The participants will be 18 to 80 years old, healthy with newly occurring back or leg pain. The main question aims to compare a group taking active treatment and a group taking a look-alike substance containing no active treatment. All participants will answer questions on Day 1, before treatment, and on 7-day after treatment, about:
Double-blind, randomized, placebo-controlled, multi-center study of metaxalone 640 mg plus standard of care for patients with acute lumbo sacral musculoskeletal conditions with spinal stenosis and sciatica. Participants will be randomized 1:1. Following the initial pilot-study a second study will randomize a larger population of patients with appropriate power.
458 studies on the registry are indexed under Spinal Stenosis; 105 are open to participants now.
This study's planned enrollment of 50 is below the median of 80 across 281 interventional studies indexed under Spinal Stenosis.
Browse Spinal Stenosis studies →Primus Pharmaceuticals is the lead sponsor of 20 studies on the registry; 3 are open to participants now.
Of its 6 completed or terminated interventional studies of FDA-regulated products, 5 (83%) have results posted.
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Exclusion Criteria:
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Clinically significant
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Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metaxalone micronized 640 mg over encapsulated tablet Taken orally every 6 hours for 7 days
Drug: Metaxalone 640 mg Oral Tablet
Inactive placebo capsule 640 mg Taken orally every 6 hours for 7 days
Drug: Metaxalone 640 mg Oral Tablet
Metaxalone 640 mg used for the treatment of discomforts associated with acute, musculoskeletal pain.
Also known as: Skelaxin un-micronized, M640, metaxalone micronized
Change of Numeric Pain Scale
Change from Baseline in low back pain and leg pain as measured by the Numeric Pain Rating Scale (NPRS) at Day 7
Time frame: Day 1 to Day 7
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Plan to share: No
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Started Nov 2023 (actual). Primary completion is estimated for Nov 2026, 36 months after the start.
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Studies of the drug tested here: Metaxalone
Primus Pharmaceuticals