METHOCARBAMOL Drug Interactions: What You Need to Know

INTERACTIONS ATMEKSI may inhibit the effect of pyridostigmine bromide. Patients with myasthenia gravis should be monitored closely for symptoms of myasthenia gravis such as weakness. If symptoms of myasthenia gravis are observed, treatment with ATMEKSI should be stopped immediately ( 7.2 ) Laboratory test interference: Methocarbamol may cause color interference in the following screening tests: 5-hydroxyindoleacetic acid (using nitrosonaphthol reagent) and VMA (Giltow method) ( 7.3 )

7.1 CNS drugs and alcohol ATMEKSI may potentiate the effects of CNS (central nervous system) depressants and alcohol [ see Warnings and Precautions (5.1) ].

7.2 Pyridostigmine Bromide ATMEKSI may inhibit the effect of pyridostigmine bromide. Patients with myasthenia gravis should be monitored closely for symptoms of myasthenia gravis such as weakness. If symptoms of myasthenia gravis are observed, treatment with ATMEKSI should be stopped immediately.

7.3 Drug/Laboratory Test Interactions ATMEKSI may cause color interference in certain screening tests for 5-hydroxyindoleacetic acid (5-HIAA) using nitrosonaphthol reagent and in screening tests for urinary vanillylmandelic acid (VMA) using the Gitlow method.

7.1 CNS drugs and alcohol ATMEKSI may potentiate the effects of CNS (central nervous system) depressants and alcohol [ see Warnings and Precautions (5.1) ].

7.2 Pyridostigmine Bromide ATMEKSI may inhibit the effect of pyridostigmine bromide. Patients with myasthenia gravis should be monitored closely for symptoms of myasthenia gravis such as weakness. If symptoms of myasthenia gravis are observed, treatment with ATMEKSI should be stopped immediately.

7.3 Drug/Laboratory Test Interactions ATMEKSI may cause color interference in certain screening tests for 5-hydroxyindoleacetic acid (5-HIAA) using nitrosonaphthol reagent and in screening tests for urinary vanillylmandelic acid (VMA) using the Gitlow method.

CONTRAINDICATIONS: Methocarbamol Injection should not be administered to patients with known or suspected renal pathology. This caution is necessary because of the presence of polyethylene glycol 300 in the vehicle. A much larger amount of polyethylene glycol 300 than is present in recommended doses of Methocarbamol Injection is known to have increased pre-existing acidosis and urea retention in patients with renal impairment. Although the amount present in this preparation is well within the limits of safety, caution dictates this contraindication.

Methocarbamol

Injection is contraindicated in patients hypersensitive to methocarbamol or to any of the injection components.

Warnings and Precautions Since methocarbamol may possess a general CNS depressant effect, patients receiving Methocarbamol Tablets USP, 500 mg or 750 mg should be cautioned about combined effects with alcohol and other CNS depressants. Safe use of Methocarbamol Tablets USP, 500 mg and 750 mg 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, Methocarbamol Tablets USP, 500 mg and 750 mg 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 PRECAUTIONS, PREGNANCY).

Use In Activities Requiring Mental

Alertness Methocarbamol may impair mental and/or physical abilities required for performance of hazardous tasks, such as operating machinery or driving a motor vehicle. Patients should be cautioned about operating machinery, including automobiles, until they are reasonably certain that methocarbamol therapy does not adversely affect their ability to engage in such activities. Information for Patients 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.

Drug Interactions

See WARNINGS and PRECAUTIONS 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.

Drug/Laboratory

Test Interactions Methocarbamol may cause a color interference in certain screening tests for 5-hydroxyindoleacetic acid (5-HIAA) using nitrosonaphthol reagent and in screening tests for urinary vanillylmandelic acid (VMA) using the Gitlow method. Carcinogenesis, Mutagenesis, Impairment of Fertility Long-term studies to evaluate the carcinogenic potential of methocarbamol have not been performed. No studies have been conducted to assess the effect of methocarbamol on mutagenesis or its potential to impair fertility.

Pregnancy Teratogenic Effects Pregnancy

Category C Animal reproduction studies have not been conducted with methocarbamol. It is also not known whether methocarbamol can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity.

Methocarbamol

Tablets USP, 500 mg and 750 mg should be given to a pregnant woman only if clearly needed. Safe use Methocarbamol Tablets USP, 500 mg and 750 mg 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, Methocarbamol Tablets USP, 500 mg and 750 mg 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 WARNINGS).

Nursing Mothers

Methocarbamol and/or its metabolites are excreted in the milk of dogs; however, it is not known whether methocarbamol or its metabolites are excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Methocarbamol Tablets USP, 500 mg or 750 mg is administered to a nursing woman.

Pediatric Use

Safety and effectiveness of Methocarbamol Tablets USP, 500 mg and 750 mg in pediatric patients below the age of 16 have not been established.