Robaxin Information
Robaxin ()
Robaxin () Description
Robaxin () /Robaxin () -750 (methocarbamol tablets, USP), 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 CHNO. 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 -hexane.
Robaxin () is available as a light orange, round, film-coated tablet containing 500 mg of methocarbamol, USP for oral administration. The inactive ingredients present are corn starch, FD&C Yellow 6, hydroxypropyl cellulose, hypromellose, magnesium stearate, polysorbate 20, povidone, propylene glycol, saccharin sodium, sodium lauryl sulfate, sodium starch glycolate, stearic acid, titanium dioxide.
Robaxin () -750 is available as an orange capsule-shaped, film-coated tablet containing 750 mg of methocarbamol, USP for oral administration. In addition to the inactive ingredients present in Robaxin () , Robaxin () -750 also contains D&C Yellow 10.
Robaxin () 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.
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.
Robaxin () Indications And Usage
Robaxin () and Robaxin () -750 are 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.
Robaxin () Contraindications
Robaxin () and Robaxin () -750 are contraindicated in patients hypersensitive to methocarbamol or to any of the tablet components.
Robaxin () Warnings
Since methocarbamol may possess a general CNS depressant effect, patients receiving Robaxin () or Robaxin () -750 should be cautioned about combined effects with alcohol and other CNS depressants.
Safe use of Robaxin () and Robaxin () -750 has not been established with regard to possible adverse effects upon fetal development. There have been reports of fetal and congenital abnormalities following in utero exposure to methocarbamol. Therefore, Robaxin () and Robaxin () -750 should not be used in women who are or may become pregnant and particularly during early pregnancy unless in the judgment of the physician the potential benefits outweigh the possible hazards (see ).
Robaxin () Precautions
Patients should be cautioned that methocarbamol may cause drowsiness or dizziness, which may impair their ability to operate motor vehicles or machinery.
Because methocarbamol may possess a general CNS-depressant effect, patients should be cautioned about combined effects with alcohol and other CNS depressants.
See and for interaction with CNS drugs and alcohol.
Methocarbamol may inhibit the effect of pyridostigmine bromide. Therefore, methocarbamol should be used with caution in patients with myasthenia gravis receiving anticholinesterase agents.
Robaxin () Adverse Reactions
Adverse reactions reported coincident with the administration of methocarbamol include:
Robaxin () Overdosage
Limited information is available on the acute toxicity of methocarbamol. Overdose of methocarbamol is frequently in conjunction with alcohol or other CNS depressants and includes the following symptoms: nausea, drowsiness, blurred vision, hypotension, seizures, and coma.
In post-marketing experience, deaths have been reported with an overdose of methocarbamol alone or in the presence of other CNS depressants, alcohol or psychotropic drugs.
Robaxin () Dosage And Administration
Robaxin () (methocarbamol), 500 mg – Adults:Initial dosage: 3 tablets q.i.d.Maintenance dosage: 2 tablets q.i.d.Robaxin () -750 (methocarbamol): 750 mg – Adults:Initial dosage: 2 tablets q.i.d.Maintenance dosage: 1 tablet q.4h. or 2 tablets t.i.d.
Six grams a day are recommended for the first 48 to 72 hours of treatment. (For severe conditions 8 grams a day may be administered). Thereafter, the dosage can usually be reduced to approximately 4 grams a day.
Robaxin () How Supplied
Robaxin () (methocarbamol tablets, USP)500 mg tablets are light orange, round, film-coated tablets engraved with Robaxin () 500 on the unscored side and SP above the score on the other side. They are supplied as follows:
Robaxin () -750 (methocarbamol tablets, USP)750 mg tablets are orange, capsule-shaped, film-coated tablets engraved with Robaxin () 750 on one side and SP on the other. They are supplied as follows:
Robaxin ()
Robaxin () Principal Display Panel - Mg Label
Robaxin () Principal Display Panel - Mg Label
