As with other agents administered either intravenously or intramuscularly, careful supervision of dose and rate of injection should be observed. Rate of injection should not exceed 3 mL per minute–i.e., one 10 mL vial in approximately three minutes.
Since ROBAXIN Injectable is hypertonic, vascular extravasation must be avoided. A recumbent position will reduce the likelihood of side reactions.
Blood aspirated into the syringe does not mix with the hypertonic solution. This phenomenon occurs with many other intravenous preparations. The blood may be injected with the methocarbamol, or the injection may be stopped when the plunger reaches the blood, whichever the physician prefers.
The total dosage should not exceed 30 mL (three vials) a day for more than three consecutive days except in the treatment of tetanus.
Caution should be observed in using the injectable form in patients with suspected or known seizure disorders.
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.
Fertility
Animal reproductive studies have not been conducted with methocarbamol. It is also not known whether methocarbamol can cause foetal harm when administered to a pregnant woman or can affect reproduction capacity.
Pregnancy
Safe use of methocarbamol has not been established with regard to possible adverse effects upon foetal development. There have been very rare reports of foetal and congenital abnormalities following in utero exposure to methocarbamol. Therefore methocarbamol tablets should not be used in women who are or may become pregnant and particularly during early pregnancy unless in the judgement of the physician the potential benefits outweigh the possible hazards.
Breastfeeding
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 Robaxin-750 is administered to a nursing woman.
Methocarbamol Pregnancy Warnings
Animal reproduction studies have not been conducted. There have been very rare reports of fetal and congenital abnormalities following in utero exposure to this drug. This drug should not be used in early pregnancy unless in the judgment of the physician the potential benefits outweigh the potential harm. There are no controlled data in human pregnancy.
US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
Use is not recommended unless clearly needed
US FDA pregnancy category: C
Comments: There have been reports of fetal and congenital abnormalities following in utero exposure.