How Long Does Soma (Carisoprodol) Stay in Your System?

Soma (Carisoprodol) in Your Blood, Urine, Hair, & Saliva

Soma (carisoprodol) is a muscle relaxant and is used to help relieve pain and discomfort caused by strains, sprains, and other muscle injuries.

Soma works by affecting the communication between nerves in the central nervous system. It produces muscle relaxation and pain relief.

Soma is available in tablets and it is also available in combination products that include aspirin or codeine and aspirin. It is taken several times a day as prescribed. You should take Soma with milk or food as it can cause an upset stomach.

How Soma Affects Your System

Carisoprodol is broken down into meprobamate in the body, which is also active in its effects. Carisoprodol is absorbed and begins to have effects after 30 minutes and the effects last for 4 to 6 hours.

Peak concentrations are seen in an hour for carisoprodol and almost three hours for its meprobamate metabolite.

The half-life of carisoprodol is about 100 minutes, but depending on individual metabolism that can be extended for up to three times as long. The half-life of meprobamate is very long, between 6 and 17 hours, which can lead to accumulation with multiple doses.

Both carisoprodol and its metabolite meprobamate are excreted in the urine and can be detected for several days after use.


To prevent side effects and drug interactions, be sure to discuss all prescription and nonprescription medications you are taking or plan to take with your doctor. Especially discuss muscle relaxants, sedatives, sleeping pills, tranquilizers, vitamins, and medications for allergies, coughs, or colds.

Your metabolism of Soma can be affected if you have ever had liver or kidney disease.

If you are pregnant, breastfeeding, or plan to become pregnant, discuss with your doctor what the implications may be for taking Soma.

Soma can make you drowsy, so it's important to take precautions for driving or operating machinery.

Side effects can include headache, fast heartbeat, drowsiness, confusion, slowed thinking, upset stomach, skin rash, and sluggish movements.

Severe Side Effects

Soma should be taken exactly as directed. To avoid the following severe side effects, do not take more than prescribed or take it more often than directed by your healthcare provider.

  • Difficulty breathing
  • Fever
  • Weakness
  • Burning in the eyes

Contact your doctor immediately or call 911 if you have any of these symptoms. In very large doses, Soma will produce a meprobamate overdose, which can include coma.

With long-term use, you may also develop tolerance and experience mild withdrawal symptoms that can last for 2 to 4 days after your last dose.

How Long Soma Stays in Your System

If you abruptly discontinue using Soma after long-term use, you may experience mild withdrawal symptoms 12 to 48 hours after your last dose, and these symptoms can last for another 12 to 48 hours.

Carisoprodol and meprobamate can be detected on a screen for prescription or over-the-counter drugs in blood and urine, as may be done in the case of a suspected overdose. They typically aren't included in a urine drug screen such as done for employment. However, if you are taking the combination product that includes codeine, that will be detected. Be sure to disclose your medications to the testing lab so they are able to better interpret the test results.

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Article Sources
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  1. U.S. Food & Drug Administration. Highlights of prescribing information. Soma (carisoprodol) tablets for oral use, CIV. Updated April 2019.

  2. U.S. National Library of Medicine, National Center for Biotechnology Information. PubChem Database. Carisoprodol. 

  3. Wang G, Huynh K, Barhate R, et al. Validation of a new homogeneous immunoassay for the detection of carisoprodol in urineJ Anal Toxicol. 2011;35(2):108–112. doi:10.1093/anatox/35.2.108

  4. Gatch MB, Nguyen JD, Carbonaro T, Forster MJ. Carisoprodol tolerance and precipitated withdrawalDrug Alcohol Depend. 2012;123(1-3):29–34. doi:10.1016/j.drugalcdep.2011.10.010

  5. Gunchan P, Parshotam GL, Garg R. Carisoprodol withdrawal syndrome resembling neuroleptic malignant syndrome: Diagnostic dilemma. J Anaesthesiol Clin Pharmacol. 2016;32(3):387-388. doi:10.4103/0970-9185.173346

Additional Reading
  • Carisoprodol. MedlinePlus NIH.

  • Carisoprodol (And Meprobamate). National Highway Traffic Safety Administration.

  • Test ID: PDSU Drug Screen, Prescription/OTC, Urine. Mayo Medical Laboratories.