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Carisoprodol: 7 things you should know

Medically reviewed by C. Fookes, BPharm Last updated on Oct 7, 2019.

1. How it works

  • Carisoprodol is a muscle relaxant.
  • Experts aren't exactly sure how carisoprodol works but believe it alters nerve activity and the propagation of electrical impulses in the spinal cord and brain.
  • Carisoprodol belongs to the group of drugs known as centrally acting skeletal muscle relaxants. It belongs to the class of muscle relaxants known as carbamates.

2. Upsides

  • Used to relieve pain associated with muscle spasm or musculoskeletal conditions in adults.
  • Generic carisoprodol is available.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Sedation, which may affect a person's ability to drive or operate machinery and increase their risk of falls. Alcohol should be avoided.
  • Dizziness, headache, heart palpitations and a drop in blood pressure on standing have also been reported. Facial flushing, insomnia, nausea and abdominal discomfort may also occur.
  • Carisoprodol may be addictive and carries a potential for abuse. May be sought after by drug abusers or people with addiction disorders. Misuse may cause sudden death or cardiovascular events (such as heart attack or stroke). Sudden discontinuation may precipitate withdrawal symptoms, including insomnia, vomiting, abdominal cramps, headache, muscle twitching, and hallucinations. Tolerance has developed to its effect (this means that the same dosage no longer provides the same relief).
  • Should only be used for short periods of time (no more than two or three weeks).
  • Rarely, may cause seizures, particularly when used with other seizure-inducing drugs.
  • May not be as effective in people classed as "poor metabolizers" as the drug undergoes activation in the liver, specifically through an enzyme called CYP2C19. Poor metabolizers make less active drug from carisoprodol.
  • Not approved for adolescents younger than 16 years old.
  • May not be suitable for some people such as those with acute porphyria, kidney or liver disease, reduced CYP2C19 activity, a history of drug or alcohol abuse, or with certain psychiatric comorbidities.
  • May interact with a number of other drugs including other drugs that cause sedation, such as benzodiazepines, alcohol, antidepressants, opioid analgesics and drugs metabolized by CYP2C19 hepatic enzymes.
  • Carisoprodol is a Schedule IV controlled substance.

Notes: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. For a complete list of all side effects, click here.

4. Bottom Line

Carisoprodol is a muscle relaxant; however, its use is limited by its potential for dependence, sedative effects, and short-lasting duration of action requiring multiple doses per day.

5. Tips

  • May be administered with or without food.
  • Carisoprodol should only be used for a maximum of two to three weeks at a time. Take exactly as directed, do not increase the dosage without your doctor's advice. Do not stop carisoprodol suddenly; when the time comes to discontinue it, your doctor will advise you how to taper the dosage down. If carisoprodol is not making your muscle pain any better, talk with your doctor.
  • Do not drive or operate machinery if carisoprodol makes you sleepy. Avoid alcohol because alcohol may make the sleepiness worse.
  • Administer at the lowest effective dosage and take exactly as directed by your doctor; never increase the dosage of carisoprodol without your doctor's advice. Avoid sudden discontinuation as this can precipitate a withdrawal reaction.
  • Talk to your doctor if you think you have become addicted to carisoprodol or if you experience any intolerable side effects.
  • Always talk to your doctor or pharmacist before buying anything over-the-counter to check if it is compatible with carisoprodol.

6. Response and Effectiveness

  • Peak effects are reached within 1.5 to two hours after a single dose. Carisoprodol is usually given three times a day but may need to be given up to four times a day.
  • Carisoprodol works in the brain and does not directly relax muscles.

7. Interactions

Medicines that interact with carisoprodol may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with carisoprodol. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with carisoprodol include:

  • acrivastine
  • anti-anxiety medications
  • anticonvulsants such as carbamazepine or phenytoin
  • antidepressants, such as amitriptyline, imipramine, nortriptyline, and monoamine oxidase inhibitors
  • antihistamines that cause sedation, such as diphenhydramine
  • aspirin
  • botulinum toxin
  • carbinoxamine
  • clopidogrel and ticlopidine
  • doxylamine
  • methyldopa
  • opioid analgesics such as oxycodone and morphine
  • other muscle relaxants such as cyclobenzaprine
  • other medications that are metabolized through CYP2C19
  • sleeping pills and other medications that have drowsiness as a side effect
  • sodium oxybate
  • some medications used to treat mental illness, such as clozapine and thioridazine.

Alcohol may worsen the side effects of carisoprodol such as drowsiness and dizziness.

Note that this list is not all-inclusive and includes only common medications that may interact with carisoprodol. You should refer to the prescribing information for carisoprodol for a complete list of interactions.

References

Carisoprodol. Revised 06/2019. Drugs.com https://www.drugs.com/ppa/carisoprodol.html

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use carisoprodol only for the indication prescribed.

Copyright 1996-2019 Drugs.com. Revision date: October 6, 2019.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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