Carisoprodal, Urine
| NAME OF DRUG: CARRISOPRODAL (SOMA) |
| PHYSICAL CHARACTERISTICS: Carisoprodal is a white crystalline powder and is available by prescription in tablet form. |
| DOSAGE/OCCURRENCE/USAGE: Carisoprodal is a carbamate derivative used primarily as a muscle relaxant. It is administered orally in doses of 200-350 mg. In certain preparations it is found in combination with such drugs as phenacetin, caffeine and codeine. |
| BLOOD CONCENTRATIONS VS. DOSAGE: No information has appeared relating to blood or plasma concentrations of carisoprodal after ingestion of therapeutic amounts. |
| URINE EXCRETION RATE: Carisoprodal is known to be metabolized to meprobamate and hydroxymeprobamate. Less than 1% of a single 350 mg oral dose is excreted unchanged in the 24 hour urine, with meprobamate accounting for 4.7% of the dose. Meprobamate and the hydroxylated metabolites may be partially excreted as conjugates. |
| METABOLITES: Meprobamate, Hydroxymeprobamate. |
| TOXICITY: Overdosage with carisoprodal has resulted in several isolated instances of drug intoxication. One stuporous patient was found to have a blood concentration of 31 mg/L using a specific gas chromatographic method. By means of a similar procedure, serum concentrations of 36 and 15 mg/L, respectively, were found for carisoprodal and its active metabolite, meprobamate, 4.5 hours after the ingestion of 3500 mg by a 5 year old child; at the same time urine concentrations of 24 and 166 mg/L were observed for the two drugs. The patient remained comatose until his death approximately 40 hours after ingestion. Two adults who ingested 8.4 and 9.5 g of carisoprodal and survived were observed to develop maximal serum carbamate concentrations of 37-38 mg/L, as measured by a nonspecific method. A fatality due solely to the ingestion of carisoprodal was found to have concentrations of 110 mg/L in the blood and 165 mg/L in the urine by gas chromatography. |
| REFERENCES: Baselt RC. Disposition of Toxic Drugs
and Chemicals in Man, Second Edition. Davis, Calif.: Biomedical Publications, 1982. Clarke EGC. Isolation and Identification of Drugs. London: The Pharmaceutical Press, 1969. |