Metaxalone
Metaxalone is a prescription muscle relaxant used along with rest and physical therapy to relieve discomfort from short-term, painful muscle and bone conditions.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 64 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
How we combine label and product data →
Metaxalone (Skelaxin) is an older muscle relaxant, on the market since about 1962 and available as a generic, used short term with rest and physical therapy for sudden, painful muscle and bone problems in adults and teens 13 and older. It likely works by calming the brain and spinal cord, not the muscle itself. It is generally seen as one of the less sedating muscle relaxants, yet drowsiness and dizziness are still what most people notice. The one thing to look for is extra sleepiness or slowed breathing when it is combined with alcohol, opioids, benzodiazepines or other sedating medicines.
Clinical pearls
- Do not switch between Skelaxin and other metaxalone tablet strengths yourself; they are not interchangeable milligram for milligram.
- Antidepressants, tramadol, triptans and some opioids raise the risk of serotonin syndrome, marked by agitation, fever, fast heartbeat and twitching.
- If you check urine sugar with a Benedict’s-type test, metaxalone can give a false positive; a glucose-specific test tells the difference.
- It is not for severe liver or kidney disease or a tendency to drug-induced anemia; report yellowing skin or eyes promptly.
Patient information guide — a plain-language walkthrough of Metaxalone, written from its FDA label.
What Metaxalone is used for
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Metaxalone is a muscle relaxant used for short-term muscle and bone pain.
- Metaxalone 640 mg tablets: relief of discomfort from acute, painful musculoskeletal conditions, as an add-on to rest, physical therapy and other measures.
- For adults and teens 13 years and older.
How Metaxalone works
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How metaxalone works hasn't been established. It may act through general depression (slowing) of the central nervous system. It has no direct action on muscle fibers, the motor end plate (where nerves meet muscle) or the nerve fiber.
Metaxalone dosage
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Metaxalone 640 mg tablets are taken by mouth, with or without food, three to four times a day. The label sets a daily maximum, so never take more than your prescriber directs.
- Metaxalone 640 mg tablets and Skelaxin 800 mg tablets are not interchangeable milligram for milligram.
- If you are switching from Skelaxin, your prescriber will give specific instructions.
- People who take either product with food should not switch between them.
Dosing details from the FDA-approved label
From the Metaxalone prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Adults and pediatric patients 13 years of age and older
- 640 mg taken orally with or without food, three to four times a day
- Maximum: 2,560 mg daily (one tablet four times a day)
- Metaxalone Tablets, 640 mg and SKELAXIN 800 mg are not mutually substitutable on a mg-to-mg basis due to differences in pharmacokinetic profiles
- Switching from SKELAXIN 800 mg taken on an empty stomach to Metaxalone Tablets, 640 mg
- Stop SKELAXIN 800 mg three times a day and start Metaxalone Tablets 640 mg three times a day on an empty stomach, OR stop SKELAXIN 800 mg four times a day and start Metaxalone Tablets 640 mg four times a day on an empty stomach
- For patients who have been taking either product with food, do not switch between SKELAXIN 800 mg and Metaxalone Tablets, 640 mg
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION The recommended dosage of Metaxalone Tablets, 640 mg in adults and pediatric patients 13 years of age and older is 640 mg taken orally with or without food, three to four times a day. The maximum recommended daily dosage is 2,560 mg (one tablet four times a day). Metaxalone Tablets, 640 mg and SKELAXIN 800 mg are not mutually substitutable on a mg-to-mg basis due to differences in pharmacokinetic profiles [see Warnings and Precautions (5.3) and Clinical Pharmacology (12.3) ]. When it is appropriate to switch a patient taking SKELAXIN 800 mg on an empty stomach to Metaxalone Tablets, 640 mg: Stop SKELAXIN 800 mg three times a day and start Metaxalone Tablets 640 mg three times a day on an empty stomach, OR Stop SKELAXIN 800 mg four times a day and start Metaxalone Tablets 640 mg four times a day on an empty stomach. For patients who have been taking either product with food, do not switch between SKELAXIN 800 mg and Metaxalone Tablets, 640 mg. Recommended dosage in adults and pediatric patients 13 years of age and older is 640 mg taken orally, with or without food, three to four times a day ( 2 ) Maximum recommended daily dosage is 2,560 mg (one tablet four times a day) ( 2 ) Metaxalone Tablets 640 mg and SKELAXIN 800 mg tablets are not mutually substitutable on a mg-to-mg basis due to differences in pharmacokinetic profiles ( 5.3 , 12.3 ). When it is appropriate to switch a patient taking SKELAXIN 800 mg on an empty stomach to Metaxalone Tablets, 640 mg ( 2 ): Stop SKELAXIN 800 mg three times a day and start Metaxalone Tablets 640 mg three times a day on an empty stomach OR Stop SKELAXIN 800 mg four times a day and start Metaxalone Tablets 640 mg four times a day on an empty stomach. For patients who have been taking either product with food, do not switch between SKELAXIN 800 mg and Metaxalone Tablets, 640 mg ( 2 ).
Read the full Dosage and Administration section on DailyMed →
Metaxalone side effects
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Common side effects
- Drowsiness
- Dizziness
- Headache
- Nervousness or irritability
- Nausea
- Vomiting
- Stomach upset
When to get medical help
- Get help right away for signs of serotonin syndrome: agitation, hallucinations, fast heartbeat, fever, stiff or twitchy muscles, poor coordination, vomiting or diarrhea.
- Get help for signs of a severe allergic reaction (anaphylaxis), or a rash with or without itching.
- Call your doctor if you notice yellowing of the skin or eyes (jaundice).
- Call your doctor about signs of anemia, including hemolytic anemia (red blood cells breaking down), or a low white blood cell count (leucopenia).
- Seek urgent help for extreme sleepiness or slowed or trouble breathing.
The most common side effects are:
- Drowsiness
- Dizziness
- Headache
- Nervousness or irritability
- Nausea and vomiting
- Stomach upset
Less common but serious reactions include severe allergic reactions, serotonin syndrome, low white blood cells, hemolytic anemia, jaundice and rash. Get medical help right away if you notice these.
Metaxalone warnings and precautions
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- Serotonin syndrome: potentially life-threatening. It can occur with other serotonergic drugs or with metaxalone alone above the recommended dose. Stop the drug and get help if it is suspected.
- Central nervous system depression: can impair driving and other hazardous tasks. Older adults may be more susceptible. Watch for sedation and slowed breathing.
- Switching products: changing from Skelaxin 800 mg to metaxalone 640 mg milligram for milligram can significantly increase drug exposure.
Metaxalone interactions
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These can add to metaxalone’s effects or raise the risk of serious reactions:
- Alcohol, benzodiazepines, opioids and tricyclic antidepressants: added sedation and slowed breathing.
- SSRIs, SNRIs, triptans, 5-HT3 blockers, mirtazapine, trazodone, tramadol, and opioids such as fentanyl, meperidine and methadone: risk of serotonin syndrome.
- MAO inhibitors, linezolid and intravenous methylene blue: risk of serotonin syndrome.
- Benedict’s urine sugar tests: may give false positives.
Interactions listed in the FDA-approved label
From the Metaxalone prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.
- Serotonergic drugs (SSRIs, SNRIs, TCAs, triptans, 5-HT3 receptor antagonists, opioids particularly fentanyl, meperidine, and methadone, mirtazapine, trazodone, tramadol, MAO inhibitors, linezolid, intravenous methylene blue): Serotonin syndrome has resulted from concomitant use of metaxalone tablets (within the recommended dosage range) with other serotonergic drugs. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dosage modification. Discontinue metaxalone tablets if serotonin syndrome is suspected or if it occurs.
- CNS depressants: Due to the additive pharmacologic effect, concomitant use may increase the risk of sedation and respiratory depression. If concomitant use is warranted, closely monitor for signs of respiratory depression and sedation, particularly during treatment initiation and dosage increases.
- Benedict's tests: False-positive Benedict's tests, due to an unknown reducing substance, have been noted in metaxalone tablets-treated patients. A glucose-specific test will differentiate findings.
Read the label’s full interactions text
7 DRUG INTERACTIONS 7.1 Serotonergic Drugs If concomitant use of metaxalone tablets and another serotonergic drug is warranted, carefully observe the patient, particularly during treatment initiation and dosage modification. Discontinue metaxalone tablets if serotonin syndrome is suspected or if it occurs. Serotonin syndrome has resulted from concomitant use of metaxalone tablets (within the recommended dosage range) with other serotonergic drugs [see Warnings and Precautions ( 5.1 ) and Adverse Reactions ( 6 )]. Serotonergic drugs include selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), triptans, 5-HT3 receptor antagonists, opioids (particularly fentanyl, meperidine, and methadone), drugs that affect the serotonergic neurotransmitter system (e.g., mirtazapine, trazodone, tramadol), and drugs that impair metabolism of serotonin (including monoamine oxidase (MAO) inhibitors, both those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue). 7.2 CNS Depressants If concomitant use of metaxalone tablets and another CNS depressant is warranted, closely monitor for signs of respiratory depression and sedation, particularly during treatment initiation and dosage increases. Due to the additive pharmacologic effect, concomitant use of metaxalone tablets with other CNS depressants may increase the risk of sedation and respiratory depression [see Warnings and Precautions ( 5.2 )]. 7.3 Interaction of Metaxalone Tablets with Benedict’s Tests False-positive Benedict's tests, due to an unknown reducing substance, have been noted in metaxalone tablets-treated patients. A glucose-specific test will differentiate findings.
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking Metaxalone
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- Do not use with a known allergy to any ingredient.
- Do not use with a known tendency for drug-induced, hemolytic or other anemias.
- Do not use with severe kidney or liver impairment. Use caution with mild to moderate impairment.
- Pregnancy: no human data are available.
- Breastfeeding: no data are available, so talk with your prescriber.
- Children: not established for ages 12 and younger.
- Older adults: may be more sensitive to central nervous system effects. The label dose is the same as for younger adults.
Metaxalone overdose
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Deaths from accidental or deliberate overdose have occurred, especially when combined with alcohol or other sedating drugs. Signs can include extreme drowsiness, agitation, hallucinations, seizures, slowed breathing, coma, fast heartbeat and blood pressure changes. Serotonin syndrome can also occur. Treatment is supportive care. Call Poison Help at 1-800-222-1222 or seek emergency care.
What Metaxalone does in the body
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The relationship between metaxalone levels and its safety and effectiveness has not been fully characterized. It does not act directly on muscle fibers or nerves. Its effects may come from general central nervous system depression.
How your body processes Metaxalone
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After a dose taken fasting, blood levels peak in about 3 hours. The half-life is about 9 hours. Taking it with a high-fat meal raises how much drug is absorbed and delays the peak. Older adults have higher exposure when fasting.
The liver breaks metaxalone down using several CYP enzymes. The breakdown products leave in the urine. It does not significantly block or boost major CYP enzymes.
How to store Metaxalone
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Store at 20° to 25°C (68° to 77°F) .
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Supplements & herbs that interact with Metaxalone
20 supplements and herbal products have documented interactions with Metaxalone in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 2
- Moderate · 9
- Minor · 9
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Metaxalone: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Metaxalone — the kind of thing our pharmacy team would talk through with you at the counter.
What is metaxalone for?
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How should I take it?
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What side effects should I expect?
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Can I drink alcohol with it?
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Do I need to tell you about my other medicines?
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Who shouldn't take it?
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Is Metaxalone available over the counter?
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When was Metaxalone first available?
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Who makes Metaxalone?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Metaxalone on HelloPharmacist
Metaxalone forms and strengths (how it comes)
Metaxalone is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Tablet
How this form is used
- Metaxalone 640 mg tablets are used with rest and physical therapy for discomfort from acute, painful musculoskeletal conditions in adults and teens 13 and older.
- Metaxalone 640 mg tablets are taken by mouth with or without food, three to four times a day.
- Metaxalone 640 mg tablets and Skelaxin 800 mg tablets are not mutually substitutable on a mg-to-mg basis.
- Do not switch between Skelaxin 800 mg and metaxalone 640 mg tablets without your prescriber’s guidance, especially if you take either with food.
Metaxalone on the U.S. market: products, makers and brands
How Metaxalone appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
32 companies list 57 Metaxalone product records with the FDA, mostly as tablet; the earliest marketing or approval year on record is 2000. Brand names on the directory include Skelaxin; the rest are generics.
Also listed with the FDA, not a patient dose form: Powder (13) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
How widely Metaxalone is used (Medicaid data)
A general measure of how commonly Metaxalone is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Metaxalone is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Metaxalone prescribed? Of the 1,601 medications we measure, Metaxalone ranks #773 by Medicaid prescriptions — more than 52% of them.
Utilization by Metaxalone product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
metaxalone 800 MG Oral Tablet Most dispensed
Summed across the 9 of 302 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 351254
metaxalone 640 MG Oral Tablet
Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2627781
metaxalone 400 MG Oral Tablet
Summed across the 2 of 8 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 197935
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Metaxalone, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 12 of 312 listed Metaxalone NDCs with Medicaid activity.
Compare Metaxalone products
A representative set of FDA-listed product records for Metaxalone — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Tablet | ||||
| 800 mg | Oral | A-S Medication Solutions × 2 listings | ANDA | View NDC → |
| 800 mg | Oral | Actavis Pharma, Inc. | ANDA | View NDC → |
| 800 mg | Oral | Advanced Rx of Tennessee, LLC × 3 listings | ANDA | View NDC → |
| 800 mg | Oral | Advanced Rx Pharmacy of Tennessee, LLC × 2 listings | ANDA | View NDC → |
| 800 mg | Oral | American Health Packaging | ANDA | View NDC → |
| 800 mg | Oral | Amneal Pharmaceuticals LLC | ANDA | View NDC → |
| 400 mg | Oral | Amneal Pharmaceuticals of New York LLC | ANDA | View NDC → |
| 800 mg | Oral | Amneal Pharmaceuticals of New York LLC | ANDA | View NDC → |
| 800 mg | Oral | Asclemed USA, Inc. × 2 listings | ANDA | View NDC → |
| 800 mg | Oral | AvKARE | ANDA | View NDC → |
| 800 mg | Oral | AvPAK | ANDA | View NDC → |
| 400 mg | Oral | Blue Heron Pharmaceuticals, LLC | ANDA | View NDC → |
| 800 mg | Oral | BluePoint Laboratories | ANDA | View NDC → |
| 800 mg | Oral | Bryant Ranch Prepack × 6 listings | ANDA | View NDC → |
| 400 mg | Oral | Cipla Usa Inc. | ANDA | View NDC → |
| 800 mg | Oral | Direct Rx | ANDA | View NDC → |
| 800 mg | Oral | Direct_Rx | ANDA | View NDC → |
| 800 mg | Oral | Doc Rx × 2 listings | ANDA | View NDC → |
| 800 mg | Oral | Dr. Reddys Laboratories Limited | ANDA | View NDC → |
| 400 mg | Oral | Highmark Pharma LLC | ANDA | View NDC → |
| 640 mg | Oral | INA Pharmaceutics Inc | NDA | View NDC → |
| 800 mg | Oral | Lannett Company, Inc. | ANDA | View NDC → |
| 800 mg | Oral | Major Pharmaceuticals | ANDA | View NDC → |
| 400 mg | Oral | Misemer Pharmaceuticals, Inc. | ANDA | View NDC → |
| 800 mg | Oral | Northwind Health Company, LLC × 2 listings | ANDA | View NDC → |
| 800 mg | Oral | PD-Rx Pharmaceuticals, Inc. × 2 listings | ANDA | View NDC → |
| 800 mg | Oral | Phoenix Rx Llc × 2 listings | ANDA | View NDC → |
| 800 mg | Oral | Preferred Pharmaceuticals, Inc. | ANDA | View NDC → |
| 800 mg | Oral | Preferred Pharmaceuticals Inc. × 2 listings | ANDA | View NDC → |
| 800 mg | Oral | Proficient Rx LP × 4 listings | ANDA | View NDC → |
| 800 mg | Oral | Quality Care Products, LLC | ANDA | View NDC → |
| 800 mg | Oral | Remedyrepack Inc. × 2 listings | ANDA | View NDC → |
| 400 mg | Oral | ScieGen Pharmaceuticals, Inc. | ANDA | View NDC → |
| 800 mg | Oral | ScieGen Pharmaceuticals, Inc. | ANDA | View NDC → |
| 800 mg | Oral | Sportpharm LLC × 2 listings | ANDA | View NDC → |
| 800 mg | Oral | St. Mary's Medical Park Pharmacy × 2 listings | ANDA | View NDC → |
Showing 57 of 57 products — FDA National Drug Code Directory. See every product, package size and price: browse all 57 Metaxalone NDCs →
Metaxalone side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Metaxalone — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Metaxalone in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Metaxalone FDA approval history
How Metaxalone went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Metaxalone recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list no Metaxalone recalls since July 2021.
✅No Metaxalone recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 59078 1 dose form · 3 strengths
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Dose form (SCDF) Oral Tablet RxCUI 372801In current FDA listings
Look up RxCUI 59078 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Metaxalone supply and shortage status
Whether Metaxalone is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
Metaxalone brand names
Metaxalone is sold under one brand name in the FDA directory — Skelaxin. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Metaxalone: manufacturers and labelers
32 companies list Metaxalone products with the FDA. By number of product records, the largest are Bryant Ranch Prepack, Proficient Rx LP, Advanced Rx of Tennessee, LLC. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
…and 8 more on the FDA NDC directory.
Metaxalone drug class (RxNorm)
Metaxalone belongs to the Muscle Relaxant class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this Metaxalone page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. INA Pharmaceutics Inc is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →