The present status of meprobamate ingestion. A five-year review of cases with serum concentrations and clinical findings

Carisoprodol: an unrecognized drug of abuse

During a 6-month monitoring period, carisoprodol was detected in the urine specimens of 19 patients for whom drug screening had been ordered for purposes of patient care. The clinical history suggested that in 7 cases the drug was abused or implicated in a suicide attempt or gesture. In another 7 cases, the drug was used primarily for medical purposes, and in 5 cases the reason for use could not be determined. One patient ingested homemade tablets that were found to contain carisoprodol. In an additional case, the drug was detected in breast milk. Physical findings, clinical history, and treatment are described, and the profile of a typical carisoprodol user is discussed. It seems that carisoprodol has become an unrecognized drug of abuse, at least in our community. This drug and its metabolite, meprobamate, should be included in comprehensive drug screening.

Naloxone potentiates anxiolytic-like actions of diazepam, pentobarbital and meprobamate but not those of Ro19-8022 in the rat

The elevated plus-maze test was used to determine if the opiate antagonist naloxone could potentiate the anxiolytic-like effects of the benzodiazepine diazepam, the barbiturate pentobarbital, the propanediol carbamate meprobamate and the partial benzodiazepine receptor agonist [R]-1-[(10-chloro-4-oxo-3-phenyl-4H-benzo[a]quinolizin-1-yl) carbonyl]-2-pyrrolidine-methanol (Ro19-8022) in the rat. A subeffective dose of each of these compounds was combined with naloxone, 10 mg/kg. Naloxone had no effect by itself, but potentiated all drugs except Ro19-8022. The proportion of entries on the open arm increased while the total number of arms entries was not modified. These results coincide with and extend data previously obtained in the mouse. One possible explanation for naloxone's effect could be that it blocks opioid inhibition of GABAergic (gamma-aminobutyric acid) neurons thereby enhancing the effects of benzodiazepines. Another possibility is that naloxone blocks opioid effects on adenosinergic systems.

Flumazenil reversal of carisoprodol (Soma) intoxication

A 52-year-old woman presented with central nervous system depression and a Glasgow Coma Score of 9 secondary to ingestion of carisoprodol, a centrally acting muscle relaxant analgesic. After administration of i.v. flumazenil, the patient's neurologic status normalized and she required no further therapy. Carisoprodol and its active sedative-hypnotic metabolite, meprobamate, are gamma aminobutyric acid receptor indirect agonists with central nervous system chloride ion channel conduction effects similar to the benzodiazepines, thus making flumazenil a potentially useful antidote in toxic presentations.

The safety of fentanyl use in the emergency department

Fentanyl citrate is a synthetic narcotic 1,000 times as potent as meperidine. It produces minimal hemodynamic effects and is characterized by a rapid onset of sedation and analgesia, a relatively short duration of action (approximately 30 to 40 minutes), and rapid reversal with opiate antagonists. These properties make fentanyl an ideal drug for emergency department use. The safety of fentanyl use in an adult ED population has not previously been studied. We retrospectively reviewed the charts of 841 patients who received fentanyl at the University of Cincinnati Center for Emergency Care between January 1985 and June 1988. The study population included 497 (59%) men and 344 (41%) women, with an average age of 33 years. The average dose of fentanyl was 180 micrograms (range, 25 to 1,400 micrograms). Six patients (1%) experienced mild side effects including nausea (one), emesis (two), urticaria (one), and pruritus (two). Nine patients (1%) developed more serious complications including six cases (0.7%) of respiratory depression and three cases (0.4%) of hypotension. Two of 183 patients (1%) who received midazolam and two of nine patients (22%) who received haloperidol developed respiratory depression. Four of the six patients with respiratory depression and two of the three patients with hypotension were intoxicated. All of the complications were transient, and none resulted in hospitalization. We conclude that fentanyl is a safe drug for use in the ED. To maximize safety, we recommend careful dosing and titration, close patient monitoring, and the availability of naloxone hydrochloride and resuscitation equipment.(ABSTRACT TRUNCATED AT 250 WORDS)

Interpretation of blood glutethimide, meprobamate, and methyprylon concentrations in nonfatal and fatal intoxications involving a single drug

We evaluated blood concentrations of three nonbarbiturate sedative-hypnotics in 19 nonfatal (NF) and five fatal (F) intoxications which were "pure" (i.e. which involved only one drug each): glutethimide, 4 (NF), 3 (F); meprobamate, 9 (NF), 1 (F); and methyprylon, 6 (NF), 1 (F). For each of the 24 cases, both a comprehensive toxicology panel (including blood and urine) and the clinical history established that only a single drug had been ingested. Blood drug concentrations showed statistically significant correlation with the level of consciousness for nonfatal meprobamate intoxication (p less than 0.01) and nonfatal methyprylon intoxication (p less than 0.05). Blood glutethimide concentrations did not show such correlation. Death was associated with a mean blood glutethimide concentration in excess of 4.0 mg/dL, a blood meprobamate concentration of 20.5 mg/dL, and a blood methyprylon concentration of 11.7 mg/dL. Interpretation of blood concentrations of these compounds is discussed, and physical findings and demographic data are presented.