Study to Assess Drowsiness, Cognition, Fall Risk After Metaxalone 640 mg and Metaxalone 800 mg

A Prospective, Randomized, Single-blind, Pilot Study to Assess Drowsiness, Cognition, and Fall Risk Following Oral Metaxalone 640 mg (M640) Versus Metaxalone 800 mg in Healthy Subjects"

Every participant will receive Metaxalone in two (2) stages, one week after the other. A single dose of each Metaxalone dose will be taken one (1) time after a high fat meal which must be eaten within 30 minutes. Every participant will be given written tests to measure drowsiness, reaction time and thinking process and will also be asked to take walking tests to assess fall risk. Participation in this study will last approximately 2-4 weeks.

Study Overview

• Status: Completed
• Conditions: Healthy Participants
• Intervention / Treatment: Drug: Metaxalone m640 mg oral tablet; Drug: Metaxalone 800 mg oral tablet

Detailed Description

The Screening-Baseline Visit will include vital signs and urine testing, and a discussion of medications and current medical history. Participants will be given written tests to measure drowsiness, reaction time and thinking process and will also be asked to take walking tests to assess fall risk.

Visit 2 approximately one to two (1 to 2) week(s) later will be the first dosing day (Arm 1) after eating the high fat meal. The testing from Baseline will be repeated four (4) hours after the medication dose is taken.

Visit 3 approximately one (1) week later will be the second dosing day (Arm 2) after eating the high fat meal. The testing from Baseline will be repeated four (4) hours after the medication dose is taken.

The End of Study safety visit will take place one (1) week after Visit 3 by phone with a discussion of any side effects from the drug, recent medications, and any illness or injury experienced since the previous visit. Participants will be given end of study and discharge instructions.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Phase 4

Contacts and Locations

Study Locations

• United States
  • Ohio
    • Columbus, Ohio, United States, 43213
      • ClinOhio Research Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Weigh at least 120 pounds at Screening
• Medically healthy with no clinically significant medical co-morbidities impact endpoints

Exclusion Criteria:

• Current use of any medications known to affect sleep-wake cycle.
• Known sleep disorder.
• Current use of cimetidine.
• Current use of a monoamine oxidase Inhibitor (MAOI), selective serotonin reuptake inhibitor (SSRI), selective norepinephrine reuptake inhibitor (SNRI), 5- hydroxytryptamine (5-HT) agonist or any drug that has the potential to affect the serotonergic neurotransmitter system (e.g. mirtazapine, trazodone, tramadol).
• Positive urine test for amphetamines, barbiturates, cocaine, opiates, benzodiazepines, or cannabinoids.
• Participants taking skeletal muscle relaxants or sedative hypnotics.
• Participants with gastrointestinal disease affecting absorption.
• Participants with severe hepatic or renal impairment.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Non-Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Active 640 mg; Metaxalone (M640) 640 mg tablet, a single-dose at visit 2 of 4 visits.	Drug: Metaxalone m640 mg oral tablet; Metaxalone partially micronized 640 mg tablet; Other Names: m640
Active Comparator: Active 800 mg; Metaxalone 800 mg tablet, a single-dose at Visit 3 of 4 visits.	Drug: Metaxalone 800 mg oral tablet; Metaxalone non-micronized 800 mg oral tablet; Other Names: Skelaxin

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of participants unable to maintain Tandem Stand Position for more than 10 seconds (position 3 of the 4-Stage Balance Test).	Validated 4-Stage Balance Test after completion of an FDA standardized high-fat meal. Place one foot in front of the other, heel touching toes.	Baseline, Visit 2 dosing (Day 1), Visit 3 dosing (Day 8)
Change from baseline of gait during a stopwatch timed, stand, and walk activity from a seated position along a 30 foot path	Timed Up and Go with Triaxial Accelerometry	Baseline, Visit 2 dosing (Day 1), Visit 3 dosing (Day 8)
Change from baseline of correct number of steps taken on a fixed 4 inch wide, 9 feet long path	Tandem Walk Test	Baseline, Visit 2 dosing (Day 1), Visit 3 dosing (Day 8)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline of participants' subjective report of drowsiness on a 10-point scale	Karolinska Sleepiness Scale where 1 = extremely alert and 10 = extremely sleepy, can't keep awake	Baseline, Visit 2 dosing (Day 1), Visit 3 dosing (Day 8)
Change from baseline of reaction to stimulus by computer generated visual prompts measured in milliseconds	Reaction Time Test (RTT)	Baseline, Visit 2 dosing (Day 1), Visit 3 dosing (Day 8)
Change from baseline of participants' reasoning ability to recognize differences in six (6) computer generated shapes for 30 minutes	Creyos Cognitive Test	Baseline, Visit 2 dosing (Day 1), Visit 3 dosing (Day 8)
The number of product related adverse events experienced by participants from Visit 2 through Visit 4	Adverse and Serious Adverse Events	Visit 2 dosing (Day 1, Visit 3 dosing (Day 8), Visit 4 End of Study (Day 15)

Collaborators and Investigators

• Sponsor: Primus Pharmaceuticals
• Collaborators: ClinOhio Research Services, LLC
• Investigators: Study Director: J Lukban, DO, Primus Pharmaceuticals, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): May 16, 2024
• Primary Completion (Actual): September 5, 2024
• Study Completion (Actual): October 30, 2024

Study Registration Dates

• First Submitted: March 30, 2024
• First Submitted That Met QC Criteria: March 30, 2024
• First Posted (Actual): April 4, 2024

Study Record Updates

• Last Update Posted (Actual): August 7, 2025
• Last Update Submitted That Met QC Criteria: August 5, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Sleepiness; Anti-Infective Agents; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Peripheral Nervous System Agents; Enzyme Inhibitors; Protein Synthesis Inhibitors; Neuromuscular Agents; Oxazolidinones; Metaxalone
• Other Study ID Numbers: PMMD-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No