carisoprodol (isomeprobamate)

carisoprodol (isomeprobamate)

(kar eye soe proe' dol)

Soma

Pregnancy Category NR

Drug class

Centrally acting skeletal muscle relaxant

Therapeutic actions

Precise mechanism not known; chemically related to meprobamate, an anxiolytic; has sedative properties; also found in animal studies to inhibit interneuronal activity in descending reticular formation and spinal cord; does not directly relax tense skeletal muscles.

Indications

·        Relief of discomfort associated with acute, painful musculoskeletal conditions as an adjunct to rest, physical therapy, and other measures

Contraindications and cautions

·        Contraindicated with allergic or idiosyncratic reactions to carisoprodol, meprobamate (reported cross-reactions with meprobamate); acute intermittent porphyria, suspected porphyria, lactation.

·        Use cautiously with renal or hepatic impairment, pregnancy.

Available forms

Tablets—350 mg

Dosages

ADULTS AND CHILDREN > 12 YR

350 mg PO tid–qid; take last dose hs.

PEDIATRIC PATIENTS

Not recommended for children < 12 yr.

GERIATRIC PATIENTS OR PATIENTS WITH HEPATIC OR RENAL IMPAIRMENT

Dosage reduction may be necessary; monitor closely.

Pharmacokinetics

Route	Onset	Peak	Duration
Oral	30 min	1–2 hr	4–6 hr

Metabolism: Hepatic; T_1/2: 8 hr

Distribution: May cross placenta; enters breast milk

Excretion: Urine

Adverse effects

·        CNS: Dizziness, drowsiness, vertigo, ataxia, tremor, agitation, irritability

·        CV: Tachycardia, orthostatic hypotension, facial flushing

·        GI: Nausea, vomiting, hiccups, epigastric distress

·        Hypersensitivity: Allergic or idiosyncratic reactions (seen with first to fourth dose in patients new to drug)—rash, erythema multiforme, pruritus, eosinophilia, fixed drug eruption; asthmatic episodes, fever, weakness, dizziness, angioneurotic edema, smarting eyes, hypotension, anaphylactoid shock

Nursing considerations

Assessment

·        History: Allergic or idiosyncratic reactions to carisoprodol, meprobamate; acute intermittent porphyria, suspected porphyria; lactation

·        Physical: T; skin color, lesions; orientation, affect; P, BP, orthostatic BP; bowel sounds, liver evaluation; LFTs, renal function tests, CBC

Interventions

·        WARNING: Monitor patient for potentially serious idiosyncratic reactions—most likely with first few doses.

·        Reduce dose with liver dysfunction.

·        Provide safety measures if CNS effects occur.

·        Drug may be habit forming. Monitor patient.

Teaching points

·        Take this drug exactly as prescribed; do not take a higher dosage; take with food if GI upset occurs.

·        Avoid alcohol, sleep-inducing, or over-the-counter drugs; these could cause dangerous effects; if you feel you need one of these preparations, consult your health care provider.

·        You may experience these side effects: Drowsiness, dizziness, vertigo (avoid driving or activities that require alertness); dizziness when you get up or climb stairs (avoid sudden changes in position, use caution climbing stairs); nausea (take drug with food; eat frequent small meals); insomnia, headache, depression (transient effects).

·        Report rash, severe nausea, dizziness, insomnia, fever, difficulty breathing.

Adverse effects in Italic are most common; those in Bold are life-threatening.