Robaxisal (Methocarbamol)

ROBAXISAL® ROBAXISAL® EXTRA STRENGTH

Whitehall-Robins

Methocarbamol – ASA

Skeletal Muscle Relaxant – Analgesic

Action And Clinical Pharmacology: The mechanism of action of methocarbamol has not been established, but may be due to general CNS depression. It has no direct action on the contractile mechanism of striated muscle, the motor end plate or the nerve fibre. Methocarbamol is metabolized to yield a dealkylated and a hydroxylated product. These 2 metabolites are found primarily as glucuronide and sulfate conjugates. Based on elimination of radioactivity, the half-life of methocarbamol and its metabolites is bout 2 hours. Animal studies reveal that methocarbamol crosses the placental barrier and blood-brain barrier.

ASA interferes with the production of prostaglandins in various organs and tissues through acetylation and inactivation of the enzyme cyclooxygenase. The main action of the drug is thought to be peripheral; however, it may have similar activity in the CNS. The reduction in tissue levels of prostaglandins may be responsible for the analgesic and anti-inflammatory effects of the drug. ASA is most effective against pain of low to moderate intensity associated with inflammation.

Indications And Clinical Uses: Pain due to or associated with skeletal muscle spasm such as acute and chronic back strains and sprains, whiplash and other traumatic injuries, myositis, pain and spasm associated with arthritis, torticollis, joint strains and sprains, bursitis, low back pain due to ill defined causes.

Contra-Indications: Methocarbamol or salicylate sensitivity; patients who have had a bronchospastic reaction, generalized urticaria, angioedema, severe rhinitis, laryngeal edema or shock precipitated by ASA or nonsteroidal anti-inflammatory drugs. Some patients sensitive to ASA, may be cross-sensitive to other nonsteroidal anti-inflammatory drugs. Patients with asthma associated nasal poylps have an increased risk of sensitivity to ASA.

Do not use in patients with active peptic ulcer.

This product should not be used in children, teenagers, and young adults with varicella or influenza, unless directed by a physician.

Precautions:

Occupational Hazards: Methocarbamol may impair the ability of the patient to engage in potentially hazardous activities such as operating machinery or driving a motor vehicle; ambulatory patients should therefore be cautioned accordingly. Patients should be cautioned about combined effects of methocarbamol with alcohol and with other CNS depressants.

Methocarbamol may cause a color interference in screening tests for 5-hydroxyindoleacetic acid (5-HIAA) and vanillylmandelic acid (VMA).

Pregnancy: Safe use in pregnancy has not been established with regard to possible adverse effects in fetal development.

Lactation: It is not known whether methocarbamol is excreted in human milk.

Children: Safety and effectiveness in children 12 years of age and less have not been established.

Use with caution in patients with active or a history of gastrointestinal ulcerations. Concomitant ingestion of alcohol increases the risk of gastrointestinal bleeding.

Use cautiously in patients with decreased renal function, bleeding tendencies, significant anemia, hypoprothrombinemia, thrombocytopenia, vitamin K deficiency and severe hepatic damage.

Discontinue 5 to 7 days prior to elective surgery because of increased risk of bleeding.

Adverse Reactions: The most frequent adverse reaction to methocarbamol is dizziness, lightheadedness and nausea. Less frequent reactions are drowsiness, blurred vision, headache, fever, allergic manifestations such as urticaria, pruritus and rash (seen in approximately 4 to 5% of patients). Adverse reactions associated with the use of ASA include nausea and other gastrointestinal discomforts, gastritis, gastric erosion, vomiting, constipation, diarrhea, angioedema, asthma, rash, pruritus, urticaria. Gastrointestinal discomfort may be minimized by administering with food.

Symptoms And Treatment Of Overdose: Symptoms: drowsiness, dizziness, rapid and deep breathing, nausea, vomiting, vertigo, tinnitus, flushing, sweating, thirst and tachycardia. In more severe cases, acid-base disturbances including respiratory alkalosis and metabolic acidosis can occur. Severe case may show fever, hemorrhage, excitement, confusion, convulsions or coma and respiratory failure.

Treatment: Reduction of dosage. Supportive therapy for 24 hours. In children with salicylate intoxication, sodium bicarbonate is recommended. Judicious use of 5% carbon dioxide with 95% oxygen may be of benefit. Abnormal electrolyte patterns should be corrected with appropriate fluid therapy.

Dosage And Administration: Robaxisal Tablets/Caplets: Adults: 2 caplets/tablets 4 times a day. 3 caplets/tablets 4 times a day may be given in severe conditions for 1 to 3 days in patients well able to tolerate salicylates.

Robaxisal Extra Strength: Adults: maximum 2 caplets, 4 times daily.

Availability And Storage: Robaxisal: Caplets: Each pink and white, coated caplet, white layer monogrammed “WR”, contains: methocarbamol 400 mg and ASA 325 mg. Nonmedicinal ingredients: cellulose, cornstarch, FD&C Red No. 3, magnesium stearate, polyethylene glycol, povidone, sodium lauryl sulfate, sodium starch glycolate, stearic acid and water. Energy:
Tablets: Each pink and white tablet, white layer monogrammed “WR”, contains: methocarbamol 400 mg and ASA 325 mg. Nonmedicinal ingredients: cornstarch, FD&C Red No. 3, magnesium stearate, povidone, sodium lauryl sulfate, sodium starch glycolate, stearic acid and water. Energy:
Robaxisal Extra Strength: Each pink and white, coated caplet, white layer monogrammed “W-R”, pink layer scored and engraved “EX”, contains: methocarbamol 400 mg and ASA 500 mg. Nonmedicinal ingredients: cellulose, cornstarch, FD&C Red No. 3, magnesium stearate, polyethylene glycol, povidone, sodium lauryl sulfate, sodium starch glycolate and stearic acid. Energy:

ROBAXISAL® ROBAXISAL® EXTRA STRENGTH Whitehall-Robins Methocarbamol – ASA Skeletal Muscle Relaxant – Analgesic

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