Pharm

Carisoprodol

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Carisoprodol, Soma, Carisoprodol Poisoning, Soma Overdose

  • Precautions
  1. Schedule IV drug in U.S. as of January 2012
  2. Risk of transient neurologic changes, serious Allergic Reactions, Substance Abuse, and fatal Overdoses
  3. Metabolized to Meprobamate, a Sedative and FDA controlled substance similar to Barbiturates
  4. Two tablets (700 mg dose) may require Endotracheal Intubation in infants
  • Mechanism
  1. Carisoprodol is a centrally acting Skeletal Muscle Relaxant
  2. Meprobamate is primary active metabolite
    1. Barbiturate-like effects at GABA-A Receptors
  • Dosing
  1. Carisoprodol (Soma) 350 mg up to four times daily
  • Pharmacokinetics
  1. Rapid absorption
  2. Rapid onset
  3. Drug Clearance (variable)
    1. Half-Life: 100 minutes
    2. Hepatic metabolism: CYP2C19
    3. Renal Excretion
  1. Myoclonic encephalopathy (abnormal movements)
  2. Agitation
  3. Lethargy to coma (Meprobamate related)
  4. Seizures (rare)
  5. Cardiopulmonary depression (apnea, Acute Heart Failure)
  6. Withdrawal symptoms (e.g. Delirium) after cessation
  • Labs
  • Toxicity
  1. See Unknown Ingestion
  2. Complete Blood Count (CBC)
  3. Comprehensive Metabolic Panel (Chem18)
  4. Creatinine Kinase (CK)
  • Diagnostics
  • Toxicity
  • Management
  • Toxicity
  1. Supportive Care
    1. ABC Management
    2. Endotracheal Intubation as indicated
  2. Gastric Decontamination is not typically indicated
  3. Sedation for Agitation, rigidity
  4. Antidotes
    1. May consider Flumazenil (but risk of severe withdrawal if concurrent Benzodiazepine Abuse)
    2. Roberge (2000) J Emerg Med 18(1):61-4 +PMID: 10645840 [PubMed]
  • References
  1. Sun and Tomaszewski (2017) Crit Dec Emerg Med 31(12): 24
  2. Høiseth (2008) Clin Toxicol 46(4):307-9 +PMID: 18363125