Skeletal Muscle Relaxant
Action and Clinical
Carisoprodol produces muscle relaxation in animals by blocking interneuronal activity in the descending reticular formation and spinal cord. There are no peripheral or autonomic effects. Clinically, carisoprodol relieves muscle spasm and associated pain in patients with painful musculoskeletal disorders. The onset of action is rapid; effects last 4 to 6 hours.
In dogs, no withdrawal symptoms occurred after abrupt cessation of carisoprodol in doses as high as 1 g/kg/day.
In a study in humans, abrupt cessation of 100 mg/kg/day (about 5 times the recommended daily adult dosage) was followed in some subjects by mild withdrawal symptoms such as abdominal cramps, insomnia, chilliness, headache, and nausea. Such signs are classified as mild to moderate by the World Health Organization and are not considered specific abstinence signs. Delirium and convulsions, which are considered specific, did not occur in this study. In clinical use, psychological dependence and abuse have been rare, and there have been no reports of significant abstinence signs. Nevertheless, the drug should be used with caution in addiction-prone individuals.
Carisoprodol is metabolized by the liver and excreted in the urine as metabolites. The half-life is approximately 8 hours.
Indications And Clinical Uses:
As an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculo-skeletal conditions. The mode of action of this drug has not been clearly identified, but may be related to its sedative properties. Carisoprodol does not directly relax tense skeletal muscles in humans.
Previous allergic or idiosyncratic reactions to carisoprodol or related compounds such as meprobamate.
On very rare occasions, the first dose of carisoprodol has been followed by idiosyncratic symptoms appearing within minutes or hours. Symptoms reported include: extreme weakness, transient quadriplegia, dizziness, ataxia, temporary loss of vision, diplopia, mydriasis, dysarthria, agitation, euphoria, confusion, and disorientation. Symptoms usually subside over the course of the next several hours. Supportive and symptomatic therapy, including hospitalization, may be necessary.
Since the effects of carisoprodol and alcohol or carisoprodol and other CNS depressants may be additive, appropriate caution should be exercised. The drug should be used with caution in addiction prone individuals.
Since carisoprodol has a chemical structure similar to meprobamate, it should be used with caution in patients with known porphyria.
Occupational Hazards: Patients receiving carisoprodol should be cautioned about driving a motor vehicle or operating machinery or apparatus requiring alert attention.
Pregnancy and Lactation: Safe usage of this drug in pregnancy has not been established. Therefore, the expected benefits must be weighed against the potential hazards. Carisoprodol is present in breast milk of lactating mothers at concentrations two to four times that of maternal plasma. This factor should be taken into account when use of the drug is contemplated in nursing mothers.
Children: Because of limited clinical experience, carisoprodol is not recommended for use in patients under 12 years of age.
CNS: Drowsiness and other CNS effects may require dosage reduction. Also observed: dizziness, vertigo, ataxia, tremor, agitation, irritability, headache, depressive reactions, syncope, and insomnia (see also Precautions).
Allergic or idiosyncratic: Allergic or idiosyncratic reactions rarely develop. They are usually seen within the period of the first to fourth dose in patients having had no previous contact with the drug. Skin rash, erythema multiforme, pruritus, eosinophilia, and fixed drug eruption with cross reaction to meprobamate have been reported with carisoprodol. Severe reactions have been manifested by asthmatic episodes, fever, weakness, dizziness, angioneurotic edema, smarting eyes, hypotension, and anaphylactoid shock (see also Precautions).
Cardiovascular: tachycardia, postural hypotension, facial flushing.
Gastrointestinal: nausea, vomiting, hiccup, epigastric distress.
Hematologic: Leukopenia, in which other drugs or viral infection may have been responsible, and pancytopenia, attributed to phenylbutazone, have been reported. No serious blood dyscrasias have been attributed to carisoprodol.
Symptoms And Treatment Of Overdose:
Overdose Symptoms: Drowsiness, dizziness, headache. Overdosage of carisoprodol has produced stupor, coma, shock, respiratory depression, and very rarely, death.
Treatment: Gastric lavage followed by the administration of activated charcoal. In children, induce emesis and if there is no immediate response, use gastric lavage. Symptomatic therapy. Should respiration or blood pressure become compromised, respiratory assistance, symptomatic cautious use of pressor amines is indicated. Although overdosage experience is limited, the following types of treatment have been used successfully with the related drug, meprobamate: forced diuresis, peritoneal dialysis and hemodialysis (carisoprodol is dialyzable). Careful monitoring of urinary output is necessary and caution should be taken to avoid overhydration. In treating severe reactions, discontinue carisoprodol and initiate appropriate symptomatic therapy.
Dosage & Administration:
Usual adult dose is 350 mg 3 times daily and at bedtime; use in patients under age 12 is not recommended.
Availability And Storage:
Each white, round, biconvex, uncoated tablet, with 37-WALLACE 2001 imprinted on one side, contains: carisoprodol 350 mg. Nonmedicinal ingredients: alginic acid, magnesium stearate, potassium sorbate, starch (corn) and tribasic calcium phosphate. Gluten- and tartrazine-free. Bottles of 25 and 250.
SOMA® Carter Horner Carisoprodol Skeletal Muscle Relaxant