SKELAXIN metaxalone tablet

Country: United States

Language: English

Source: NLM (National Library of Medicine)

Active ingredient:

METAXALONE (UNII: 1NMA9J598Y) (METAXALONE - UNII:1NMA9J598Y)

Available from:

Lake Erie Medical DBA Quality Care Products LLC

INN (International Name):

METAXALONE

Composition:

METAXALONE 800 mg

Prescription type:

PRESCRIPTION DRUG

Authorization status:

New Drug Application

Summary of Product characteristics

SKELAXIN- METAXALONE TABLET
LAKE ERIE MEDICAL DBA QUALITY CARE PRODUCTS LLC
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SKELAXIN
(METAXALONE) TABLETS
DESCRIPTION
SKELAXIN (metaxalone) is available as an 800 mg oval, scored pink
tablet.
Chemically, metaxalone is 5-[(3,5- dimethylphenoxy)
methyl]-2-oxazolidinone. The empirical formula is
C
H NO , 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: alginic acid, ammonium
calcium alginate, B-Rose Liquid, corn starch, and magnesium stearate.
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 SKELAXIN under fasted and fed conditions at doses
ranging from 400 mg to 800 mg.
_ABSORPTION_
Peak 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 SKELAXIN from 400 mg to 800
mg results in a roughly
proportional increase in metaxalone exposure as indicated by peak
plasma concentrations (C
) 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.
TABLE 1: MEAN (%CV) METAXALONE PHARMACOKINETIC PARAMETERS
DOSE (mg) C
(ng/mL) T
(h) AUC (ng•h/mL) T
(h)
CL/F (L