Effect of Metaxalone 640 mg (M640) on Driving, Cognition, and EEG Dynamics Compared to Tizanidine 8 mg in Adults

November 8, 2026 updated by: Primus Pharmaceuticals

Assessment of the Effect of Metaxalone Tablets, 640 mg (M640) on Driving Ability, Cognition, and Electroencephalographic (EEG) Dynamics Compared to Tizanidine 8 mg in Adult Participants: A Prospective, Single-blind, Within-subject Study

Participant takes a single pill after eating, takes a driving test on a simulator, takes thought and concentration computerized tests

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The study evaluates effects of a single-dose of M640 mg compared to a single dose of tizanidine 8 mg on driving, cognition, sleepiness, and brain activity in healthy adults

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
20

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Adults, aged ≥ 18 and ≤ 65 years of age at the time of consent.
  • Weigh at least 120 pounds at Screening/Baseline and Baseline.
  • Medically healthy
  • Able to take oral medication.
  • Possesses a valid driver's license.

Exclusion Criteria:

  • Current use of any medications known to affect sleep-wake cycle.
  • Has a sleep disorder.
  • Positive urine test for amphetamines, barbiturates, cocaine, opiates, benzodiazepines, or cannabinoids
  • Known history of alcohol or substance use disorder
  • Participants with a history of cognitive disorders, depression, schizophrenia, panic disorder, or dementia.
  • Participants with a history of seizure disorder or epilepsy.
  • Participants with scalp conditions, dermatologic disease, or hair/scalp characteristics

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Sequential Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Active metaxalone 640 mg

metaxalone 640 mg tablets, one dose only
Drug: Metaxalone Pill

micronized metaxalone 640 mg pill

Other Names:
  • m640
  • Skelaxin 640 mg
Active Comparator: Active tizanidine 8 mg

tizanidine 8 mg tablets, one dose only
Drug: tizanidine 8 mg

muscle relaxer for spasms

Other Names:
  • Zanaflex

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change from Baseline to Tmax in Standard Deviation of Lateral Position as evaluated by Driving Simulation Software
Time Frame: Baseline dose to time of maximum concentration (Tmax), metaxalone 4 hours and tizanidine 1.5 hours post dose

A hardware and software setup that recreates the experience of driving a real vehicle and measures performance at the time of maximum concentration of the drug in the body (metaxalone 4 hours and tizanidine 1.5 hours post dose)
Baseline dose to time of maximum concentration (Tmax), metaxalone 4 hours and tizanidine 1.5 hours post dose
Change from Baseline to Tmax in Cognition as assessed by Creyos Cognitive Testing (CCT).
Time Frame: Baseline dose to time of maximum concentration (Tmax), metaxalone 4 hours and tizanidine 1.5 hours post dose

Computerized thinking assessment to objectively measure brain function at the time of maximum concentration of the drug in the body (metaxalone 4 hours and tizanidine 1.5 hours post dose)
Baseline dose to time of maximum concentration (Tmax), metaxalone 4 hours and tizanidine 1.5 hours post dose

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change from Baseline to Tmax in Degree of point-in-time drowsiness as measured by the Karolinska Sleepiness Scale (KSS).
Time Frame: Baseline dose to time of maximum concentration (Tmax), metaxalone 4 hours and tizanidine 1.5 hours

Measure at Tmax (metaxalone 4 hours and tizanidine 1.5 hours post dose) Scale: 1 = Extremely alert, 2 = Very alert, 3 = Alert, 4 = Rather alert, 5 = Neither alert nor sleepy, 6 = Some signs of sleepiness, 7 = Sleepy, but no effort to keep awake, 8 = Sleepy, some effort to keep awake, 9 = Very sleepy, great effort to keep awake, fighting sleep
Baseline dose to time of maximum concentration (Tmax), metaxalone 4 hours and tizanidine 1.5 hours
Change from Baseline to Tmax in electroencephalograph measures
Time Frame: Baseline dose to time of maximum concentration (Tmax), metaxalone 4 hours and tizanidine 1.5 hours post dose

Placement of a non-invasive headset with saline filled, padded electrodes on the participant's scalp to measure brain activity with eyes open and closed at the time of maximum dose of the drug in the body (metaxalone 4 hours and tizanidine 1.5 hours post dose)
Baseline dose to time of maximum concentration (Tmax), metaxalone 4 hours and tizanidine 1.5 hours post dose

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Primus Pharmaceuticals

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: James Lukban, DO, Primus Pharmaceuticals, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 15, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 15, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 15, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 3, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 8, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 12, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 12, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • PMDAC-02

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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