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

Phase 4

Recruiting

Interventions: Drug: Metaxalone 800 mg oral tablet
Drug: Metaxalone m640 mg oral tablet

Brief Summary: 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.

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.

Recruitment & Eligibility

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.

Arm && Interventions

Group	Intervention	Description
Active 800 mg	Metaxalone 800 mg oral tablet	Metaxalone 800 mg tablet, a single-dose at Visit 3 of 4 visits.
Active 640 mg	Metaxalone m640 mg oral tablet	Metaxalone (M640) 640 mg tablet, a single-dose at visit 2 of 4 visits.

Primary Outcome Measures

Name	Time	Method
Percentage of participants unable to maintain Tandem Stand Position for more than 10 seconds (position 3 of the 4-Stage Balance Test).	Baseline, Visit 2 dosing (Day 1), Visit 3 dosing (Day 8)	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.
Change from baseline of correct number of steps taken on a fixed 4 inch wide, 9 feet long path	Baseline, Visit 2 dosing (Day 1), Visit 3 dosing (Day 8)	Tandem Walk Test
Change from baseline of gait during a stopwatch timed, stand, and walk activity from a seated position along a 30 foot path	Baseline, Visit 2 dosing (Day 1), Visit 3 dosing (Day 8)	Timed Up and Go with Triaxial Accelerometry

Secondary Outcome Measures

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