Muscle Relaxers

Carisoprodol (Soma) 350 mg

  • Generic name: Carisoprodol
  • Trade names: Carisoma, Soma, Somadril (Wallace), Vanadom
  • Dosages: 350 mg tablets
  • Pharmacologic category: Skeletal muscle relaxant
  • FDA approved: April 09, 1959
  • Habit forming? Possibly
  • Pregnancy risk factor: C

Medical uses

Carisoprodol is a centrally-acting skeletal muscle relaxant. This medicine is used to relieve stiffness, pain, and discomfort caused by strains, sprains, and other muscle injuries. It is often prescribed for back pain, fibromyalgia, arthritis pain, and pain associated with TMJ disorder.

Onset of action: rapid, within 30 min.
Duration of action: 4 to 6 hr.

In clinical trial Carisoprodol was better than propoxyphene in relieving stiffness and increasing movement. It was better than butabarbital for increasing movement and leading to general improvement. Carisoprodol was superior to diazepam for relieving the symptoms of acute lower back pain. According to the clinical data, it was similarly effective as the centrally acting muscle relaxant cyclobenzaprine. [3-6]

Legal Status of Carisoprodol

Carisoprodol was classified as a controlled substance in several US states, and effective January 11, 2012, became a schedule IV controlled substance at the US federal level7.


Carisoprodol is most often taken therapeutically in doses of 350 mg up to 3 or 4 times per day.

Carisoprodol is recommended to be used only short term (up to 3 weeks). It is not indicated for children under 12 years of age.

Pharmacological characteristics

  • Elimination half-life: 3-4 hours
  • Metabolism: metabolized to to its metabolites hydroxycarisoprodol, hydroxymeprobamate, and meprobamate in the liver via cytochrome P450 enzyme, CYP2C19.
  • Excretion: eliminated by both renal and non-renal routes. It is dialyzable by peritoneal and hemodialysis.


  • Potent muscle relaxer - for many people carisoprodol is the best out of all muscle relaxers.
  • Quick onset of pain relief.
  • Effective for muscle spasms and back pain - disrupts the spasm-pain-spasm progression, improves range of motion, and maximizes everyday functionality [1].
  • Can alleviate pain and induce sleep in fibromyalgia [2].


  • Potential for abuse and dependence. Carisoprodol itself is probably not addictive, but it is metabolized into meprobamate in the liver, which is highly addictive. The majority of cases of drug abuse, dependence and withdrawal have been reported with prolonged use of carisoprodol (beyond several months) or in combination with other CNS depressants or psychotropic drugs. However, there have been cases reported with carisoprodol alone.
  • Withdrawal symptoms following abrupt cessation after prolonged use.
  • Possible intoxication and psychomotor impairment. Carisoprodol is pretty unsafe for drivers.

Mechanism of action

Carisoprodol works by blocking nerve impulses (or pain sensations) that are sent to the brain. It interrupts neuronal communication within the reticular formation and spinal cord.

In addition to the muscle relaxing effect, carisoprodol produces weak analgesic, anti-fever, and anticholinergic action. Carisoprodol and its metabolite meprobamate have sedative and anxiolytic properties similar to benzodiazepines.

Reviews, Discussions & Forums


  • 1. Toth PP, Urtis J. Commonly used muscle relaxant therapies for acute low back pain: a review of carisoprodol, cyclobenzaprine, and metaxalone. Clin Ther. 2004 Sep;26(9):1355-67. PubMed
  • 2. Vaeroy H, Abrahamsen A, Forre O, Kass E. Fibromyalgia (fibrositis syndrome): a parallel double blind trial with carisoprodol, paracetamol and caffeine (Somadril comp) versus placebo. Clin Rheumatol. 1989 Jun;8(2):245-50. PubMed
  • 3. Hindle T. Comparison of carisoprodol, butabarbital, and placebo in low back syndrome. Calif Med. 1972;117:7-11.
  • 4. Baratta RR. A double-blind comparative study of carisoprodol, propoxyphene, and placebo in the management of low back syndrome. Curr Ther Res Clin Exp. Sep 1976;20(3):233-240.
  • 5. Boyles W, Glassmann J, Soyka J. Management of acute muskuloskeletal conditions: thoracolumbar strain and sprain. A double-blind evaluation comparing the efficacy and safety of carisoprodol with diazepam. Today's Ther Trends. 1983;1:1-16.
  • 6. Rollings H, Glassmann J, Soyka J. Management of acute musculoskeletal conditions - thoracolumbar strain and sprain: a double-blind evaluation comparing the efficacy and safety of carisoprodol with cyclobenzadrine. Curr Ther Res. 1982;34(6):917-928.
  • 7. Reeves RR, Burke RS, Kose S. Carisoprodol: update on abuse potential and legal status. South Med J. 2012 Nov;105(11):619-23.

By HealthyStock Research Group, September 2009
Medical resources reviewed: August 2018

Interesting facts


  • Carisoprodol is chemically, structurally, and pharmacologically related to meprobamate. Meprobamate is a CNS depressant with substantial barbiturate-like properties, indicated for the management of anxiety.
  • In addition to the desired skeletal muscle relaxing properties, carisoprodol produces weak anticholinergic, antipyretic and analgesic action.

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