Carisoprodol, Aspirin and Codeine Phosphate

CARISOPRODOL, ASPIRIN AND CODEINE PHOSPHATE- carisoprodol, aspirin and codeine phosphate tablet
Rising Pharmaceuticals, Inc.


Addiction, Abuse and Misuse

Carisoprodol, Aspirin and Codeine Phosphate Tablets expose patients and other users to the risks of opioid addiction, abuse and misuse, which can lead to overdose and death. Assess each patient’s risk prior to prescribing Carisoprodol, Aspirin and Codeine Phosphate Tablets, and monitor all patients regularly for the development of these behaviors and conditions (see WARNINGS).

Opioid Analgesic Risk Evaluation and Mitigation Strategy (REMS)

To ensure that the benefits of opioid analgesics outweigh the risks of addiction, abuse, and misuse, the Food and Drug Administration (FDA) has required a REMS for these products (see WARNINGS). Under the requirements of the REMS, drug companies with approved opioid analgesic products must make REMS-compliant education programs available to healthcare providers. Healthcare providers are strongly encouraged to

  • complete a REMS-compliant education program,
  • counsel patients and/or their caregivers, with every prescription, on safe use, serious risks, storage, and disposal of these products,
  • emphasize to patients and their caregivers the importance of reading the Medication Guide every time it is provided by their pharmacist, and
  • consider other tools to improve patient, household, and community safety.

Life-Threatening Respiratory Depression

Serious, life-threatening, or fatal respiratory depression may occur with use of Carisoprodol, Aspirin and Codeine Phosphate Tablets. Monitor for respiratory depression, especially during initiation of Carisoprodol, Aspirin and Codeine Phosphate Tablets or following a dose increase (see WARNINGS).

Accidental Ingestion

Accidental ingestion of even one dose of Carisoprodol, Aspirin and Codeine Phosphate Tablets, especially by children, can result in a fatal overdose of Carisoprodol, Aspirin and Codeine Phosphate Tablets (see WARNINGS).

Ultra-Rapid Metabolism of Codeine and Other Risk Factors for Life-threatening Respiratory Depression in Children

Life-threatening respiratory depression and death have occurred in children who received codeine. Most of the reported cases occurred following tonsillectomy and/or adenoidectomy, and many of the children had evidence of being an ultra-rapid metabolizer of codeine due to a CYP2D6 polymorphism (see WARNINGS). Carisoprodol, Aspirin and Codeine Phosphate Tablets are contraindicated in children younger than 12 years of age and in children younger than 18 years of age following tonsillectomy and/or adenoidectomy (see CONTRAINDICATIONS). Avoid the use of Carisoprodol, Aspirin and Codeine Phosphate Tablets in adolescents 12 to 18 years of age who have other risk factors that may increase their sensitivity to the respiratory depressant effects of codeine.

Neonatal Opioid Withdrawal Syndrome

Prolonged use of Carisoprodol, Aspirin and Codeine Phosphate Tablets during pregnancy can result in neonatal opioid withdrawal syndrome, which may be life-threatening if not recognized and treated, and requires management according to protocols developed by neonatology experts. If opioid use is required for a prolonged period in a pregnant woman, advise the patient of the risk of neonatal opioid withdrawal syndrome and ensure that appropriate treatment will be available (see WARNINGS).

Interactions with Drugs Affecting Cytochrome P450 Isoenzymes

The effects of concomitant use or discontinuation of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with codeine are complex. Use of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with Carisoprodol, Aspirin and Codeine Phosphate Tablets requires careful consideration of the effects on codeine, and the active metabolite, morphine. (See WARNINGS, PRECAUTIONS; Drug Interactions).

Risks From Concomitant Use With Benzodiazepines Or Other CNS Depressants

Concomitant use of opioids with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death (see WARNINGS, PRECAUTIONS; Drug Interactions).

  • Reserve concomitant prescribing of Carisoprodol, Aspirin and Codeine Phosphate Tablets and benzodiazepines or other CNS depressants for use in patients for whom alternative treatment options are inadequate.
  • Limit dosages and durations to the minimum required.
  • Follow patients for signs and symptoms of respiratory depression and sedation.


Carisoprodol, Aspirin and Codeine Phosphate Tablets, USP is a fixed-dose combination product containing the following three products:

  • 200 mg of carisoprodol, a centrally-acting muscle relaxant
  • 325 mg of aspirin, an analgesic with antipyretic and anti-inflammatory properties
  • 16 mg of codeine phosphate, a centrally-acting narcotic analgesic

It is available as a round, two-layered yellow and white tablet for oral administration.

Carisoprodol: Chemically, carisoprodol is N -isopropyl-2-methyl-2-propyl-1,3 propanediol dicarbamate and its molecular formula is C12 H24 N2 O4 , with a molecular weight of 260.34. The structural formula of carisoprodol is:

carisoprodol structure

Aspirin: Chemically, aspirin (acetylsalicylic acid) is 2-(acetyloxy)-, benzoic acid and its molecular formula is C9 H8 O4 , with a molecular weight of 180.16. The structural formula of aspirin is:

aspirin structure

Codeine Phosphate: Chemically, codeine phosphate is 7,8 Didehydro-4,5α-epoxy-3methoxy-17- ethylmorphinan-6α-ol phosphate (1:1) (salt) hemihydrate and its molecular formula is C18 H24 NO7 P, with a molecular weight of 406.37. The structural formula of codeine phosphate is:

codeine phosphate structure
(click image for full-size original)

Each tablet, for oral administration, contains carisoprodol 200 mg, aspirin 325 mg, and codeine phosphate 16 mg. In addition, each tablet contains the following inactive ingredients: FD&C Yellow #5 Aluminum Lake, Corn starch, Hydroxypropyl Cellulose, Lactose Anhydrous, Microcrystalline Cellulose, Magnesium Stearate, Pregelatinized Starch, Sodium Starch Glycolate and Sodium Lauryl Sulfate.


Mechanism of Action

Carisoprodol: The mechanism of action of carisoprodol in relieving discomfort associated with acute painful musculoskeletal conditions has not been clearly identified. In animal studies, muscle relaxation induced by carisoprodol is associated with altered interneuronal activity in the spinal cord and in the descending reticular formation of the brain.

Aspirin: Aspirin is a nonsteroidal anti-inflammatory drug and a non-selective irreversible inhibitor of cyclooxygenases.

The mechanism of action of aspirin in relieving pain is by inhibition of the body’s production of prostaglandins, which are thought to cause pain sensations by stimulating muscle contractions and dilating blood vessels.

Codeine Phosphate: Codeine is an opioid agonist relatively selective for the mu-opioid receptor, but with a much weaker affinity than morphine. The analgesic properties of codeine have been speculated to come from its conversion to morphine, although the exact mechanism of analgesic action remains unknown.

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