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PubMed1978

Involvement of gamma-amino butyric acid (GABA) in the anticonvulsant action of methaqualone.

The effects of methaqualone on isonicotinic acid hydrazide, 6-mercapto propionic acid, picrotoxin, and strychnine-induced convulsion were studied in mice and the results compared with diazepam. Methaqualone, like diazepam, was found to be a selective antagonist of isoniazid-induced convulsion and a much less effective inhibitor of strychnine convulsion. Methaqualone elicits muscle-relaxant, sedative, and anticonvulsant effects at different dose levels. At low, nonsedative doses the drug produces anticonvulsant effects, and at higher doses, muscle-relaxant and sedative effects. It appears that the mechanism(s) of action of methaqualone in on GABA deficiency or receptor blockade, rather than on glycine receptors.

Aminobutyrates↗
PubMed2001

A survey of reported synthesis of methaqualone and some positional and structural isomers.

Methaqualone (2-methyl-3-o-tolyl-4(3H)-quinazolinone) is the illicit synthetic drug of choice amongst South African drug users. Historically police and forensic investigation has proven that all methaqualone seized by the South African Police Service originates from illicit manufacturing sites both inside, and outside South Africa's borders. From a drug enforcement, and forensic point of view it is, thus, of utmost importance that the various synthetic routes available to the illicit "chemist" are fully documented and understood. This is a prerequisite for effective illicit laboratory investigation, as well as chemical and precursor monitoring. This paper gives a brief introduction to the current status with regard to methaqualone use and production in South Africa, as well as an extensive review of the synthesis of methaqualone and selected isomers reported since 1946. A table summarizing synthetic routes reported in 32 reference sources is provided.

Humans↗
PubMedDate not supplied

Incidence of methaqualone in driving-under-the-influence (DUI) cases in the state of Georgia.

A retrospective study was undertaken to assess the range of blood methaqualone levels, which should be considered sufficient to produce deterioration of driving ability. Data from 974 driving-under-the influence (DUI) cases were subdivided into five major catagories based on whether drugs other than methaqualone were discovered during the analytical procedures. The range of blood methaqualone levels, which appear to cause significant motor skill impairment, are discussed for each category. Also included are data from 20 of these cases indicating the symptoms of methaqualone intoxication which were reported by arresting officers.

Automobile Driving↗
PubMedDate not supplied

Peripheral neuropathy caused by methaqualone.

Three patients are described who each received methaqualone and developed signs and symptoms of peripheral neuropathy. The subsequent improvement after cessation of methaqualone was highly suggestive or a direct toxic action of the drug or one of its metabolites. In one patient methaqualone was recommended with reappearance of signs and symptoms of peripheral neuropathy. Again cessation of the drug caused disappearance of these signs. There was no evidence whatsoever of any electrolyte or metabolic disturbance or any other pathology which might have given rise to this symptom complex. In addition, no other drugs were prescribed besides methaqualone.

Adult↗
PubMed1978

Thin layer chromatographic screening for methaqualone, phenothiazines, opiates and benzodiazepines.

A method is described which permits the simultaneous detection of methaqualone, phenothiazines, opiates and benzodiazepines in urine. Its diagnostic application is discussed. After cleavage of conjugates with hydrochloric acid, the substances are extracted and identified by thin-layer chromatography. In most cases analysis can be carried out using 2 solvent systems, phenothiazines, methaqualone and opiates being visualised using a three stage spray sequence. Since phenothiazines can interfere with the detection of methaqualone, a specific eluant is used to ensure reliable detection of the latter. Methaqualone can be positively identified by its characteristic metabolite pattern, whereas phenothiazines can only be detected as a group.

Analgesics, Opioid↗
PubMed1975

Thin-layer chromatographic detection and identification of methaqualone metabolites in urine.

A procedure for detecting methaqualone and identifying methaqualone metabolites in urine by thin-layer chromatography is described and evaluated. Urine is hydrolyzed with HCl or NaIO4, adjusted to pH 9.5, and extracted with chloroform. The chloroform extract is evaporated, reconstituted in methanol, applied to fluorescent silica-gel plates, and developed with ethyl acetate:methanol:ammonium hydroxide (28%) (85:10:5 by vol). Methaqualone use is detected by a pattern of four metabolites, which can be seen under ultraviolet light or are made visible by acidified iodoplatinate reagent. Synthetic methaqualone metabolites are used for identification and to compensate for procedural variables. More than 250 positive urine specimens were correctly identified by this method. Hydrolyzed natural and synthetic metabolites were identical by several criteria.

Chromatography, Thin Layer↗
PubMed1984

Fixed drug eruption due to methaqualone.

We report three cases of fixed drug eruption due to methaqualone. Eruptions from methaqualone have been rarely reported since the drug's introduction in 1963. Our discovery of these three cases during a two-year period suggests that dermatologic reactions from methaqualone may be much more common than has been appreciated. This may be related to the reluctance of the patient to admit to the use or abuse of methaqualone, and physicians' lack of recognition of the widespread abuse of this drug and its possible cutaneous complications.

Adult↗
PubMedDate not supplied

Treatment of Methaqualone overdose with resin hemoperfusion.

We recently utilized the technique of resin hemoperfusion (employing an Amberlite XAD-4 resin cartridge) to remove drug from a patient i deep coma after an estimated ingestion of greater than 4.5 grams of methaqualone. At plasma flow rates of 204 ml/min, the mean value for plasma clearance of methaqualone was 179 ml/min. The amount of methaqualone recovered from the cartridge at the end of the 10-hour procedure was 1,565 mg measured by gas chromatography. The patient became responsive to deep pain by the end of the procedure. The only complication encountered was a transient decrease in the formed blood elements. The present study verifies that a large, pharmacologically significance quantity of methaqualone can be removed in a short time using resin hemoperfusion.

Adult↗
PubMed1977

Methaqualone metabolites in human urine after therapeutic doses.

We measured five principal metabolites of methaqualone in the urine of seven volunteers after single and multiple doses of the drug. Urine, collected for up to 72 hours after the last dose, was analyzed for methaqualone and its principal metabolites by high-resolution capillary-column gas chromatography. The major biotransformation of methaqualone under therapeutic conditions occurred through benzylic and para-hydroxylation of the o-tolyl moiety. Methaqualone itself was present in concentrations of no more than 1 mg/liter, if it could be detected at all. The observed physiological effects ant total urinary excretion of metabolites reflected the cumulative nature of the parent drug when it was administered in multiple doses. No clear relationship was found between appearance of a specific metabolite and time after ingestion of the drug, although higher amounts of 2-methyl-3-(2'-hydroxymethylphenyl)-4(3H)-quinazolinone were noted in those individuals who tolerated the drug less well.

Chromatography, Gas↗
PubMed1978

Inter- and intra-individual variation in the metabolism of methaqualone in man after a single oral dose.

The urinary excretion of five C-monohydroxy metabolites and the N-oxide metabolite of methaqualone in the 24 h period immediately after oral dosing with 250 mg methaqualone (Melsed) has been measured in ninteen healthy adults (13 male, 6 female) to assess interindividual variations and in five adults (3 male, 2 female) on five separate occasions to assess intraindividual variation. The overall importance of the six metabolites was 4'-hydroxy greater than N-oxide greater than 2'-hydroxymethyl greater than 3'-hydroxy greater than 6-hydroxy = 2-hydroxymethyl. Variations in this order both within the 24 h period and within each of the three eight-hour periods constituting the 24 hours were minor and variations in the absolute amount of each metabolie excreted ranged from two to three-fold. Intraindividual variations were generally smaller than interindividual variations and for each individual the pattern of metabolism was similar on the five occasions. There is evidence that the C-oxidation of methaqualone may be more sensitive to cyclical variations in hormone levels than is N-oxidation.

Adult↗
PubMed1975

Behavioural sequelae of methaqualone in man and in the monkey (Macaca mulatta).

1 Residual effects in man of methaqualone hydrochloride (400 mg) were studied by adaptive tracking and by reaction time. Performance was measured at 10 h, 13 h, 16 h, 19 h and 34 h after the overnight ingestion of the drug. There was no evidence of impaired performance on adaptive tracking from 10 h to 19 h, but enhanced performance (P = 0.001) was observed 34 h after ingestion. With reaction time an increase (P = 0.01) was observed 10 h and a decrease (P = 0.05) was observed 19 h after ingestion. 2 Effects in the monkey (Macaca mulatta) of methaqualone (20 and 30 mg/kg body weight) were studied by a delayed matching task in which total response time was measured. No consistent effects on matching behaviour or on total response time were observed 2 h after intraperitoneal injection. 3 The studies suggest that methaqualone hydrochloride may be a valuable hypnotic for occasional use by persons involved in skilled activity.

Animals↗
PubMed1976

Methaqualone misuse: foreign experience and United States drug control policy.

In 1972 methaqualone emerged as a major drug of nonmedical use in the United States--a subject of widespread publicity and public concern. In late 1973, government officials responded by taking the unprecedented measure of imposing the strictest controls available under United States law on a drug which had previously been subject only to a simple prescription requirement. Methaqualone had a similar history in other countries, particularly in Germany, Japan, and Great Britain. However, this history was ignored by United States officials until nonmedical methaqualone use had become a substantial problem in the United States.

Aphrodisiacs↗
PubMed1975

Methaqualone abusers: a preliminary survey of college students.

A questionnaire was used to survey the methaqualone experiences of college student users, and psychological test data from these users and a control group of non-users were compared. On differential pattern found was that methaqualone users have experimented with a wider variety of psychoactive drugs than have non-users. However, the two groups were essentially indistinguishable on the psychological test variables assessed. A preliminary modal profile of the college student methaqualone abuser and abuse experience was generated.

Adult↗
PubMed1975

Age differences affecting induction of hepatic drug metabolizing enzymes by methaqualone and phenobarbital in the rat.

Methaqualone pretreatment for 3 or 6 days caused an induction of hepatic enzymes in the young male rat as measured by a reduction in hexobarbital-hypnosis. However, methaqualone pretreatment had no effect on the hexobarbital-hypnotic response in older male rats. Phenobarbital was a more potent enzyme inducer than methaqualone, and caused induction of liver enzymes in both age groups.

Age Factors↗
PubMed1975

[Spectrophotometric determination of methaqualone in biologic material].

A rapid and simple spectrophotometric procedure for the determination of 2-methyl-3-o-tolyl-4(3H)-quinazolinone (methaqualone) in biological material is described. After extraction of the specimen with chloroform and washing with 0.5 N sodium hydroxide and 0.5 N sulfuric acid methaqualone is extracted with 5 ml 50% sulfuric acid and read in a spectrophotometer at 234 nm. The procedure is suitable to determine serum levels of methaqualone after a therapeutic dose.

Humans↗
PubMed1975

Radioimmunoassay of methaqualone and its monohydroxy metabolites in urine.

A commercial radioimmunoassay kit was evaluated for efficacy in detecting methaqualone or its metabolites in urine of persons receiving this drug. The drug and its unconjugated 3'- and 4'-monohydroxy metabolites could be detected equally well. The unconjugated alpha-monohydroxy metabolite was about 80% as reactive and the unconjugated 6-monohydroxy metabolite reacted only very weakly. Quantitation of the conjugated metabolites was less sensitive than of unconjugated. Nineteen urine specimens which reacted positively to radioimmunoassay and which thin-layer chromatography had shown to contain methaqualone and its metabolites were also examined by gas-liquid chromatography. Those specimens that reacted strongly to radioimmunoassay contained high concentrations of the drug or its metabolites. In the specimens examined by gas-liquid chromatography, the apparent concentrations of the metabolites were generally higher than those of the drug itself. Methaqualone in combination with its unconjugated metabolites reacted additively with the radioimmunoassay, resembling the same concentration of parent drug alone. Detection limits were between 10-200 mug/liter.

Chromatography, Gas↗
PubMed1976

Methaqualone metabolism by rat liver microsomes.

A rat hepatic microsomal system has been established which metabolizes methaqualone. The microsomes are obtained from livers of rats treated with phenobarbital. The methaqualone is dissolved in polyethylene glycol-200 prior to addition to the incubation mixture. A comparison is made between the metabolites obtained in this in vitro system and metabolites obtained from urines of phenobarbital treated rats injected with methaqualone. The same two and sometimes three metabolites, as determined by thin layer and gas liquid chromatography, were found in both the complete microsomal incubation system and the urines.

Animals↗
PubMed1975

A comparison of the inductive effects of phenobarbital, methaqualone, and methyprylon on hepatic mixed function oxidase enzymes in the rat.

The effects of equal doses of three sedative-hypnotics, phenobarbital, methaqualone, and methyprylon, on the hepatic mixed function oxidase enzymes of the rat were investigated and compared. After 5 days of pretreatment, phenobarbital and methyprylon significantly increased aminopyrine demethylation, aniline hydroxylation, and cytochrome P-450 content in hepatic microsomes. Methaqualone pretreatment only increased hepatic aminopyrine demethylase activity and wet liver weights. After 29 days of pretreatment, phenobarbital significantly increases aminopyrine demethylase, aniline hydroxylase activity, liver weight and cytochrome P-450 content. Methaqualone only produced a significant increase in wet liver weight.

Animals↗