carisoprodol (Rx)

>10%

Drowsiness (13-17%)

1-10%

Dizziness (7-8%)

Headache (3-5%)

Frequency Not Defined

Orthostatic hypotension

Syncope

Tachycardia

Agitation

Irritability

Depression

Allergic/idiosyncratic reactions (pruritus, rash, dizziness, etc)

Epigastric distress

N/V

Facial flushing

Weakness

Contraindications

Hypersensitivity to carisoprodol, meprobamate, mebutamate, tybamate

History of acute intermittent porphyria

Cautions

Caution in hepatic/renal impairment

May cause CNS depression; use caution when performing tasks which require mental alertness (eg, operating heavy machinery); sedating effects potentiated when used with other CNS-depressant drugs or ethanol

Severe weakness may occur

Seizures reported with its use in patients with or without seizure history

Risk of allergic reactions

Use caution in patients with history of drug abuse or acute alcoholism; drug dependency may occur and withdrawal symptoms experienced with abrupt cessation, especially with long-term use; limit use to 2-3 weeks

Pregnancy

Data over many decades of use of drug in pregnancy have not identified drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes; data on meprobamate, the primary metabolite of carisoprodol, do not show consistent association between maternal use and increased risk of major birth defects

Animal data

• In a published animal reproduction study, pregnant mice administered carisoprodol orally at 2.6- and 4.1-times maximum recommended human dose of 1400 mg per day [350 mg QID] based on body surface area comparison) from gestation through weaning resulted in reduced fetal weights, postnatal weight gain, and postnatal survival

Lactation

Data from published literature report that carisoprodol and its metabolite, meprobamate, are present in breastmilk; there are no data on effect on milk production; there is one report of sedation in an infant who was breastfed by a mother taking carisoprodol; because there have been no consistent reports of adverse events in breastfed infants over decades of use, the developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed infant or from underlying maternal condition; infants exposed to drug through breast milk should be monitored for sedation

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Not clearly known; may block interneural activity and depress polysynaptic neuron transmission

Absorption

Onset: 30 min

Duration: 4-6 hr

Peak plasma time: 1.5-2 hr

Metabolism

Metabolized by liver microsomal enzymes (CYP2C19)

Elimination

Half-life: 2 hr; meprobamate (8 hr)

Dialyzable: Yes (HD, PD)

Excretion: Urine