Methocarbamol Tablets, USP 500 mg Methocarbamol Tablets, USP 750 mg

Country: United States

Language: English

Source: NLM (National Library of Medicine)

Active ingredient:

METHOCARBAMOL (UNII: 125OD7737X) (METHOCARBAMOL - UNII:125OD7737X)

Available from:

Par Pharmaceutical

INN (International Name):

METHOCARBAMOL

Composition:

METHOCARBAMOL 500 mg

Administration route:

ORAL

Prescription type:

PRESCRIPTION DRUG

Therapeutic indications:

Methocarbamol is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions. The mode of action of methocarbamol has not been clearly identified, but may be related to its sedative properties. Methocarbamol does not directly relax tense skeletal muscles in man. Methocarbamol is contraindicated in patients hypersensitive to methocarbamol or to any of the tablet components.

Product summary:

Methocarbamol Tablets, USP 500 mg — white, round, convex face, debossed "4211" bisect over "V" on one side and plain on the reverse side. Available in bottles of 10, 100, 500 and 1000. Methocarbamol Tablets, USP 750 mg — white, capsule shape, convex face, debossed "4212" on one side and debossed "V" on the reverse side. Available in bottles of 10, 100, 500, 1000 and unit-dose packs of 100. Store at 20°– 25°C (68°– 77°F) [See USP Controlled Room Temperature]. Dispense in tight container.

Authorization status:

Abbreviated New Drug Application

Summary of Product characteristics

METHOCARBAMOL- METHOCARBAMOL TABLET
PAR PHARMACEUTICAL
----------
METHOCARBAMOL TABLETS, USP 500 MG
METHOCARBAMOL TABLETS, USP 750 MG
RX ONLY
DESCRIPTION
Methocarbamol Tablets, USP, 500 mg and 750 mg, a carbamate derivative
of guaifenesin, is a central
nervous system (CNS) depressant with sedative and musculoskeletal
relaxant properties.
The chemical name of methocarbamol is 3-(2-methoxyphenoxy)-1,
2-propanediol 1-carbamate and has
the empirical formula C
H NO . Its molecular weight is 241.24.
The structural formula is shown below.
Methocarbamol is a white powder, sparingly soluble in water and
chloroform, soluble in alcohol (only
with heating) and propylene glycol, and insoluble in benzene and
_n_-hexane.
Each tablet, for oral administration, contains either 500 mg or 750 mg
of methocarbamol, USP. The
inactive ingredients present are colloidal silicon dioxide, magnesium
stearate, povidone, pregelatinized
corn starch, purified water, sodium starch glycolate, and stearic
acid.
CLINICAL PHARMACOLOGY
The mechanism of action of methocarbamol in humans has not been
established, but may be due to
general central nervous system (CNS) depression. It has no direct
action on the contractile mechanism
of striated muscle, the motor end plate or the nerve fiber.
PHARMACOKINETICS
In healthy volunteers, the plasma clearance of methocarbamol ranges
between 0.20 and 0.80 L/h/kg, the
mean plasma elimination half-life ranges between 1 and 2 hours, and
the plasma protein binding ranges
between 46% and 50%.
Methocarbamol is metabolized via dealkylation and hydroxylation.
Conjugation of methocarbamol also
is likely. Essentially all methocarbamol metabolites are eliminated in
the urine. Small amounts of
unchanged methocarbamol also are excreted in the urine.
SPECIAL POPULATIONS
_Elderly_
The mean (± SD) elimination half-life of methocarbamol in elderly
healthy volunteers (mean (± SD) age,
11
15
5
69 (± 4) years) was slightly prolonged compared to a younger (mean
(± SD) age, 53.3 (± 8.8) years),
healthy population (1.5 (±0.4) hour