Upon analysis, this pharmacological agent seems to be an agonist of the NMDA receptor, with an unknown [Km]. Because excess Glutamate causes excitotoxicity and neuronal apoptosis, Carisoprodol overdose may also lead to NMDA related toxicity, thus inducing seizures at high doses, and muscle relaxation upon administration. Carisoprodols structural similarity to Meprobamate indicates GABAergic activity, including GABA A agonism, similar to the mechanism of benzodiazepines. This will allow for further muscle relaxation and anxiety reduction. Therefore, Carisoprodol, at low to moderate dosages, may be clinically indicated for absent seizures, yet exacerbate Tonic-clonic seizures. Pharmacokinetics
Carisoprodol has a rapid, 30-minute onset of action, with the aforementioned effects lasting about two to six hours. It is metabolized in the liver via the cytochrome P450 oxidase isozyme CYP2C19, excreted by the kidneys and has about an eight-hour half-life. In patients with low levels of CYP2C19 (poor metabolizers), standard doses can lead to increased concentrations of carisoprodol (up-to a four-fold increase). A considerable proportion of carisoprodol is metabolized to meprobamate, which is a known addictive substance; this could account for the addictive potential of carisoprodol (meprobamate levels reach higher peak plasma levels than carisoprodol itself following administration).
Carisoprodols effect profile did indeed turn out to differ significantly with respect to meprobamate, with carisoprodol possessing stronger muscle relaxant and analgesic effects. Usage and legal status
Norway
Reports from Norway have shown carisoprodol has addictive potential as a prodrug of meprobamate and/or potentiator of hydrocodone, oxycodone, codeine, and similar drugs. In May 2008 it was taken off the market in Norway. European Union
In the EU, the European Medicines Agency issued a release recommending member states suspend marketing authorization for this product in the treatment of acute (not chronic) back pain.As of November 2007, carisoprodol has been taken off the market in Sweden due to problems with dependence and side effects. The agency overseeing pharmaceuticals considered other drugs used with the same indications as carisoprodol to have the same or better effects without the risks of the drug. United States
Until 12 December 2011, when the administrator of the Drug Enforcement Administration (DEA) issued the final ruling placing the substance carisoprodol into Schedule IV of the Controlled Substances Act (CSA), carisoprodol was not a controlled substance. The placement of carisoprodol into Schedule IV was effective 11 January 2012.Carisoprodol is available generically as 350 mg and, more recently, 250 mg tablets. Compounded tablets with acetaminophen and codeine are also available. Canada
Federally, carisoprodol is a prescription drug (Schedule I, sub-schedule F1). Provincial regulations vary. It is no longer readily available. Indonesia
In September 2013, carisoprodol was taken off the market due to problems with diversion, dependence and side effects.