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

Soma in Your Blood, Urine, & Hair

Soma (carisoprodol) is a muscle relaxant and is used to help relieve pain and discomfort caused by strains, sprains, and other muscle injuries. It works by affecting the communication between nerves in the central nervous system to produce muscle relaxation and pain relief.

In the U.S., in accordance with the Controlled Substances Act, Soma is classified as a Schedule IV controlled substance. This classification means that this substance has a recognized potential for abuse and addiction.

While it varies for each person, Soma usually stays in your system for an average of 11 hours. Soma metabolites remain in your system for up to four days after you stop taking it.

Standard drug tests do not screen for Soma, so it is only be detectable if a person is specifically tested for it. Soma may be detectable on some tests for up to a month.

How Long Does Soma Stay In Your System?

Blood: Around 24 hours

Urine: Several days

Hair: Up to a month

How Long Does It Take to Feel Effects?

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. The pain-relief and muscle-relaxing effects last for 4 to 6 hours.

While Soma may also reduce feelings of anxiety, it is not FDA-approved to help with anxiety.

How Long Does Soma Last?

The half-life of carisoprodol is about 1 to 3 hours, which varies depending on individual metabolism. The half-life of meprobamate is much longer, 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 the last dose. Your metabolism of Soma can be affected if you have ever had liver or kidney disease.

Peak concentrations are seen in 1.5 to 2 hours for carisoprodol, and between 3 and 4 hours for its meprobamate metabolite.

A variety of factors can influence how long Soma stays in your system. These include:

  • Age
  • Body mass
  • Dosage of the medication
  • Genetics
  • How long you've been taking the drug
  • Metabolism
  • Overall health
  • Whether it was combined with any other substance

Factors That Affect Detection

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.

Soma may be detectable in blood for up to 24 hours, but it may show up on urine tests for several days. This period may be longer for people who have been taking Soma for a long period of time.

However, if you are taking a combination product that includes codeine, that will be detected. Be sure to disclose your medications to whoever is administering your test so they are able to better interpret the test results.


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.

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.

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

Side Effects of Soma

Soma can have side effects. Some of the most common include:

  • Confusion
  • Drowsiness
  • Fast heartbeat
  • Headache
  • Skin rash
  • Slowed thinking
  • Sluggish movements
  • Upset stomach

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

Severe Side Effects

Soma should be taken exactly as directed. To avoid these 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 can produce a meprobamate overdose, which can lead to a coma.

Getting Help

When you stop taking Soma, duration and severity of withdrawal symptoms will depend on how long the drug has been used, the level of tolerance, and the dosage. If you abruptly stop taking Soma, you may experience short-term withdrawal symptoms that can begin 12 to 24 hours after your last dose and usually resolve within 2 to 4 days.

If you are concerned about dependence or tolerance to Soma in yourself or a loved one, talk to your healthcare provider about how best to safely discontinue use. Treatment is available for addiction and overuse of prescription drugs.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area. 

For more mental health resources, see our National Helpline Database.

7 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. 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

  3. National Center for Biotechnology Information. PubChem compound summary for CID 2576, carisoprodol.

  4. McIntyre IM, Sherrard J, Lucas L. Postmortem carisoprodol and meprobamate concentrations in blood and liver: Lack of significant redistributionJ Anal Toxicol. 2012;36(3):177-181. doi:10.1093/jat/bks011

  5. U.S. National Library of Medicine. Carisoprodol.

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  7. Reeves RR, Burke RS. Carisoprodol: abuse potential and withdrawal syndrome. Curr Drug Abuse Rev. 2010;3(1):33-8. doi:10.2174/1874473711003010033

By Buddy T
Buddy T is an anonymous writer and founding member of the Online Al-Anon Outreach Committee with decades of experience writing about alcoholism.