Metaxall
Generic name:metaxalone
Dosage form: tablet
Medically reviewed by Drugs.com. Last updated on Feb 21, 2022.
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Metaxall Description
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 C12H15NO3, which corresponds to a molecular weight of 221.25. The structural formula is:
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 glycol ate and sodium stearyl fumarate.
Metaxall - Clinical Pharmacology
Mechanism of Action
The mechanism of action of metaxalone in humans has not been established, but may be due to general central nervous system depression. Metaxalone has no direct action on the contractile mechanism of striated muscle, the motor end plate or the nerve fiber.
Pharmacokinetics
The pharmacokinetics of metaxalone have been evaluated in healthy adult volunteers after single dose administration of metaxalone under fasted and fed conditions at doses ranging from 400 mg to 800 mg.
AbsorptionPeak plasma concentrations of metaxalone occur approximately 3 hours after a 400 mg oral dose under fasted conditions. Thereafter, metaxalone concentrations decline log-linearly with a terminal half-life of 9.0 ± 4.8 hours. Doubling the dose of metaxalone from 400 mg to 800 mg results in a roughly proportional increase in metaxalone exposure as indicated by peak plasma concentrations (Cmax) and area under the curve (AUC). Dose proportionality at doses above 800 mg has not been studied. The absolute bioavailability of metaxalone is not known.
The single-dose pharmacokinetic parameters of metaxalone in two groups of healthy volunteers are shown in Table 1.
