Metaxalone (Page 2 of 2)


Metaxalone is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomforts associated with acute, painful musculoskeletal conditions. The mode of action of this drug has not been clearly identified, but may be related to its sedative properties. Metaxalone does not directly relax tense skeletal muscles in man.


Known hypersensitivity to any components of this product.

Known tendency to drug induced, hemolytic, or other anemias.

Significantly impaired renal or hepatic function.


Metaxalone may enhance the effects of alcohol and other CNS depressants.


Metaxalone should be administered with great care to patients with pre-existing liver damage. Serial liver function studies should be performed in these patients.

False-positive Benedict’s tests, due to an unknown reducing substance, have been noted. A glucose-specific test will differentiate findings.

Taking metaxalone with food may enhance general CNS depression; elderly patients may be especially susceptible to this CNS effect. (See CLINICAL PHARMACOLOGY: Pharmacokinetics and PRECAUTIONS: Information for Patients section).

Information for Patients

Metaxalone may impair mental and/or physical abilities required for performance of hazardous tasks, such as operating machinery or driving a motor vehicle, especially when used with alcohol or other CNS depressants.

Drug Interactions

The sedative effects of metaxalone and other CNS depressants (e.g., alcohol, alcohol, benzodiazepines, opioids, tricyclic antidepressants) may be additive. Therefore, caution should be exercised with patients who take more than one of these CNS depressants simultaneously.

Carcinogenesis, Mutagenesis, Impairment of Fertility

The carcinogenic potential of metaxalone has not been determined.


Reproduction studies in rats have not revealed evidence of impaired fertility or harm to the fetus due to metaxalone. Post marketing experience has not revealed evidence of fetal injury, but such experience cannot exclude the possibility of infrequent or subtle damage to the human fetus. Safe use of metaxalone has not been established with regard to possible adverse effects upon fetal development. Therefore, metaxalone tablets should not be used in women who are or may become pregnant and particularly during early pregnancy unless, in the judgement of the physician, the potential benefits outweigh the possible hazards.

Nursing Mothers

It is not known whether this drug is secreted in human milk. As a general rule, nursing should not be undertaken while a patient is on a drug since many drugs are excreted in human milk.

Pediatric Use

Safety and effectiveness in children 12 years of age and below have not been established.


The most frequent reactions to metaxalone include:

CNS: drowsiness, dizziness, headache, and nervousness or “irritability”;

Digestive: nausea, vomiting, gastrointestinal upset.

Other adverse reactions are:

Immune System: hypersensitivity reaction, rash with or without pruritus;

Hematologic: leukopenia; hemolytic anemia;

Hepatobiliary: jaundice.

Though rare, anaphylactoid reactions have been reported with metaxalone.


Deaths by deliberate or accidental overdose have occurred with metaxalone, particularly in combination with antidepressants, and have been reported with this class of drug in combination with alcohol.

When determining the LD 50 in rats and mice, progressive sedation, hypnosis and finally respiratory failure were noted as the dosage increased. In dogs, no LD 50 could be determined as the higher doses produced an emetic action in 15 to 30 minutes.

Treatment — Gastric lavage and supportive therapy. Consultation with a regional poison control center is recommended.


The recommended dose for adults and children over 12 years of age is one 800 mg tablet three to four times a day.


Metaxalone is available as an 800 mg , light pink to pink, capsule shaped, scored uncoated tablet with debossing ‘AN’ on the left side of the scoring and ‘553’ on the right side of the scoring. Other side of the tablet is plain.

They are available as follows:

Bottles of 100: NDC 65162-553-10

Bottles of 500: NDC 65162-553-50

Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [See USP Controlled Room Temperature].

Rx Only

Manufactured By:
Amneal Pharmaceuticals Co. (I) Pvt. Ltd.
Ahmedabad, INDIA 382220

Distributed By:
Amneal Pharmaceuticals
Glasgow, KY 42141

Rev. 05-2012


Metaxalone is available as an 800 mg, light pink to pink, capsule shaped, scored uncoated tablet.

Chemically, metaxalone is 5-[(3,5- dimethylphenoxy) methyl]-2-oxazolidinone. The empirical formula is C 12 H 15 NO 3 , which corresponds to a molecular weight of 221.25. The structural formula is:

(click image for full-size original)

Metaxalone is a white to almost white, odorless crystalline powder freely soluble in chloroform, soluble in methanol and in 96% ethanol, but practically insoluble in ether or water.

Each tablet contains 800 mg metaxalone and the following inactive ingredients: calcium carbonate, FD&C Red #40, hypromellose, lactose monohydrate, microcrystalline cellulose, povidone, silicone dioxide, sodium starch glycolate and sodium stearyl fumarate.

Principal Display Panel

Metaxalone Tablets, 800mg

20 Tablets

NDC 10544-144-20

800mg 20ct
(click image for full-size original)
metaxalone tablet
Product Information
Product Type HUMAN PRESCRIPTION DRUG Item Code (Source) NDC:10544-144(NDC:65162-553)
Route of Administration ORAL DEA Schedule
Active Ingredient/Active Moiety
Ingredient Name Basis of Strength Strength
Inactive Ingredients
Ingredient Name Strength
Product Characteristics
Color pink (light pink to pink) Score 2 pieces
Shape CAPSULE Size 19mm
Flavor Imprint Code AN;553
# Item Code Package Description Multilevel Packaging
1 NDC:10544-144-20 20 TABLET in 1 BOTTLE None
2 NDC:10544-144-12 12 TABLET in 1 BOTTLE None
3 NDC:10544-144-30 30 TABLET in 1 BOTTLE None
4 NDC:10544-144-09 9 TABLET in 1 BOTTLE None
Marketing Information
Marketing Category Application Number or Monograph Citation Marketing Start Date Marketing End Date
ANDA ANDA203399 09/11/2013
Labeler — Blenheim Pharmacal, Inc. (171434587)
Registrant — Blenheim Pharmacal, Inc. (171434587)
Name Address ID/FEI Operations
Blenheim Pharmacal, Inc. 171434587 repack (10544-144)

Revised: 09/2015 Blenheim Pharmacal, Inc.

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