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Soma Compound - What is the half life of soma?


Official Answer Medically reviewed by C. Fookes, BPharm. Last updated on Sep 15, 2019.

Soma compound contains aspirin and carisoprodol. Aspirin reduces pain and inflammation in the body and carisoprodol is a muscle relaxant that works by blocking pain sensations that are sent to the brain. Soma Compound is a fixed-dose combination product containing 200 mg of carisoprodol and 325 mg of aspirin.

The half-life of Soma compound increases as the dosage and frequency of dosing of Soma compound increases, but is approximately 12 hours for a single dose (based on the carisoprodol, one of its ingredients, which has a combined half-life with its active metabolite meprobamate of approximately 12 hours).

How do you calculate the half-life of Soma compound?

To work out the half-life of Soma Compound we need to look at its ingredients (aspirin and carisoprodol) individually. Aspirin is metabolized very quickly by the liver to salicylic acid, which also has pain and inflammation-relieving properties, similar to aspirin.

Aspirin has a half-life of 15 to 30 minutes, whereas the half-life for salicylic acid lengthens as the dose increases. For example:

  • Aspirin 300 to 650 mg: Half-life approximately 3.1 to 3.2 hours
  • Aspirin 1 gram: Half-life approximately 5 hours
  • Aspirin 2 grams: Half-life approximately 9 hours.

Carisoprodol is metabolized by CYP2C19 enzymes in the liver, to an active metabolite called meprobamate which has both anxiety-reducing and sedative properties. The half-life of carisoprodol is approximately 2 hours and the half-life of meprobamate is 10 hours, giving a combined half-life of approximately 12 hours.

What is half-life?

The half-life of a drug is an estimate of the time it takes for the concentration or amount in the body of that drug to be reduced by exactly one half (50%).

Soma Compound contains two medicines, aspirin and carisoprodol, both of which have active metabolites, so each of these ingredients will contribute to its half-life. The combined half-life after one dose is approximately 12 hours.

After four to five half-lives, 97% of a drug has cleared from the body, and the drug is no longer considered to be having an effect, although, for most drugs, actual noticeable effects would have worn off well before then. This means it will take approximately 60 hours (five times twelve hours) for one dose of Soma to be cleared from the body.

In reality, the half-life of Soma Compound varies from person to person, and even sometimes within the same person. The half-life of Soma Compound can be affected by dosage and several other factors including:

  • Age
  • Impaired kidney function
  • Impaired liver function
  • Interacting medications
  • Pre-existing conditions
  • Regular dosing.

See our article Drug Half-life Explained for general information about half-lives.

Votes: +0
masso 2 July 2016

Carisoprodol elimination half-life is 2.44 ± 0.93 hours. So, it may take 3-4 days to clear out of the system.

See Also: Drug Half Life Explained

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