As mentioned above, carisoprodol appears to have strong anxiolytic effects on its own; however, a large part of its effects also come from the fact that it is metabolized into meprobamate: at least a 25% of the carisoprodol administered will be transformed into meprobamate which means that meprobamate is 3.25× stronger than carisoprodol (although this rate varies from person to person according to their levels of CYP2C19 enzymes in their livers with some people having considerably higher levels) or, in other words, 200 mg of meprobamate (which is the lowest standard dose) is equivalent to 650 mg of carisoprodol. As such, meprobamate is believed to play a significant role in the effects of carisoprodol and meprobamates long half-life results in bioaccumulation following extended periods of carisoprodol administration. It is slightly soluble in water and freely soluble in ethanol, chloroform and acetone. The drugs solubility is practically independent of pH. History
On 1 June 1959, several American pharmacologists convened at Wayne State University in Detroit, Michigan to discuss a newly discovered structural analogue of meprobamate. The substitution of one hydrogen atom with an isopropyl group on one of the carbamyl nitrogens was intended to yield a drug with new pharmacological properties. It had been developed by Frank Berger at Wallace Laboratories and was named carisoprodol.Building on meprobamates pharmacological effects, carisoprodol was intended to have better muscle relaxing properties, less potential for addiction, and a lower risk of overdose.
Carisoprodol is sometimes mixed with date rape drugs.Many overdoses have resulted from recreational users combining these drugs to combine their individual effects without being aware of the enzyme-induction induced potentiation. Overdose
As with other GABAergic drugs, combination with other GABAergic drugs, including alcohol, as well as with sedatives in general, possess a significant risk to the user in the form of overdose. Overdose symptoms are similar to those of other GABAergics including excessive sedation and unresponsiveness to stimuli, severe ataxia, amnesia, confusion, agitation, intoxication and inappropriate (potentially violent) behavior. Severe overdoses may present with respiratory depression (and subsequent pulmonary aspiration), coma, and death.Carisoprodol is not detected on all toxicology tests which may delay diagnosis of overdose. Overdose symptoms in combination with opiates are similar but are distinguished by the presentation of normal or pinpoint pupils, which are generally unresponsive to light. Carisoprodol (as with its metabolite meprobamate) is particularly dangerous in combination with alcohol. Flumazenil (the benzodiazepine antidote) is not effective in the management of carisoprodol overdose as carisoprodol acts at the barbiturate binding site. Treatment mirrors that of barbiturate overdoses and is generally supportive, including the administration of mechanical respiration and pressors as implicated (and in rare cases, bemegride). Total amnesia of the experience is not uncommon following recovery.In 2014 actress Skye McCole Bartusiak died of an overdose due to the combined effects of carisoprodol, hydrocodone and difluoroethane. Pharmacology
Pharmacodynamics
Carisoprodol, has a chemical structure similar to Glutamate, a neurotransmitter, and dimethylglycine.