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PubMed1978

Metabolism of methaqualone in geriatric patients.

The urinary excretion of five C-monohydroxy metabolites and the N-oxide of methaqualone has been measured in a group of eleven geriatric patients aged 71--90 years. The total excretion of the six metabolites in 24 h after the oral administration of a single dose was approximately one-half of that in a group of young healthy adults. The relative importance of the six metabolites was 4'-hydroxy greater than N-oxide greater than 2'-hydroxymethyl = 3'-hydroxy greater than 6-hydroxy = 2-hydroxymethyl which was the same order as that in young adults. The ratio of C-to N-oxidation was also the same in the two groups. There was no impairment of conjugation of the C-hydroxy metabolites with glucuronic acid in the geriatric group but there was greater interindividual variation in metabolite excretion. There was also evidence for delayed metabolism in the geriatric patients.

Aged↗
PubMed1995

[Dangerous intoxication from extreme serum concentrations of methaqualone metabolites. Detection and quantification of biosynthesis with gas chromatography-mass spectrometry].

CLINICAL COURSE: We present a potentially fatal case of acute methaqualone (M) poisoning with very low serum concentrations of M but extremely high levels of its metabolite, 2-methyl-3-(2-hydroxymethyl-phenyl)-4 (3H)-chinazoline (Met-1). A 23-year-old man was admitted to the intensive care unit 2 days after ingestion of 4-5 g M in an suicidal attempt. On admission he was somnolent and poorly responsive to painful stimuli. Physical examination revealed a heart rate of 95 bpm, a blood pressure of 125/65 mmHg, and a normal body temperature. His chest was clear to auscultation, respirations were shallow, and the skin was cyanotic. The electrocardiogram was unremarkable. The chest radiograph showed a normal heart size without pulmonary infiltrates or venous congestion. The pupils were dilated but reactive to light. The neurologic examination was further remarkable for increased limb reflexes, myoclonia, and positive pyramidal signs. During the next 2 days the patient became comatose and developed respiratory insufficiency due to non-cardiogenic pulmonary oedema, which was confirmed by chest radiograph and haemodynamic investigations by means of right heart catheterisation. He required mechanical ventilation for 6 days. Finally, he recovered completely and was discharged in good condition. DIAGNOSTICS: A lumbar puncture revealed neither blood nor pleocytosis in the cerebrospinal fluid. Cranial computed tomography was carried out on an emergency basis, but no abnormality was disclosed. An electroencephalogram did not exhibit any significant pathological findings. Testing for infectious diseases or porphyria gave negative results. Toxicological screening based on enzyme immunoassays (ELISA) was negative for alcohol, tricyclic antidepressants, benzodiazepines, barbiturates, and morphine, but gave a positive result for M. From the moment of admission daily blood samples were taken and analysed by combined gas chromatography and mass spectrometry. These showed very low levels of M but extremely high levels of Met-1. THERAPY: After gastric lavage, continuous enteric lavage with activated charcoal and mannitol was initiated to minimise intestinal absorption. Since M was hardly detectable in the serum, haemoperfusion was not regarded as indicated for drug elimination and treatment was restricted to general supportive measures. To rule out a central anticholinergic syndrome, an anticholinesterase drug (physostigmine) was administered but remained without therapeutic effect. CONCLUSIONS: The presented case is the first report of a life-threatening intoxication after M ingestion primarily caused by Met-1. It supports the significance of this metabolite for the toxic effects of the drug. A toxicological screening test based on ELISA proved helpful due to its cross-reactivity with metabolites. In cases similar to ours, resin haemoperfusion may be indicated to remove the metabolites despite low detectable concentrations of the parent substance in the serum.

Adult↗
PubMedDate not supplied

Effects of methaqualone on learning: a failure to observe tolerance.

The study was designed to assess the effects of Methaqualone (MTQ) on learning, as well as the effects of 15 days of pretask drug exposure on performance. Forty CFE rats were randomly divided into four groups: Group I received daily IP injections of MTQ for 15 days prior to and throughout the duration of the task; Group II served as a control for Group I, receiving injections of the carrier vehicle; Group III received MTO at the start and throughout the duration of the task; Group IV served as the control for Group III. The task consisted of two pretraining days of swimming down a straight, all-white alleyway, followed by 5 trials/day for 4 days on a black-white discrimination task in a water T maze, with the white side being reinforced for all animals. Analyses revealed that MTQ animals made significantly more errors than controls. Pretask drug exposure did not significantly alter Group I performance versus Group III. Furthermore, continued injections for half of the animals in Group I and II for eight days following the last learning day did not improve Group I performance when retested on the same task. Thus MTQ adversely affected learning with prolonged drug exposure failing to reverse such debilitation.

Analysis of Variance↗
PubMed1981

The effect of d-lysergic acid diethylamide (LSD), 2,5-dimethoxy-4-methylamphetamine (DOM), pentobarbital and methaqualone on punished responding in control and 5,7-dihydroxytryptamine-treated rats.

The purpose of the present study was to determine the role of central 5-hydroxytryptamine (5-HT) neuronal systems in the effects of d-lysergic acid diethylamide (LSD), 2,5-methoxy-4-methylamphetamine (DOM), pentobarbital (PB) and methaqualone (MQ) on punished responding in rats. Water-deprived rats were trained to drink from a tube that was electrified at intervals (variable interval 21 sec; 0.03 mA current intensity), electrification being signalled by a tone. In daily 10-min control sessions, these animals accepted a relatively constant number of shocks; water consumption was also quite stable. At maximally effective doses PB, and to a lesser extent MQ, produced large (400-600 percent of control) increases in punished responding with little decrease in water intake. Higher doses of these agents produced a significant depression of unpunished responding (water intake). The hallucinogens, on the other hand, produced only moderate (125-175 percent of control) increases in the number of shock received, yet a similar depression of unpunished responding. Selective destruction of 5-HT neurons by intracerebroventricular administration of the neurotoxin 5,7-dihydroxytryptamine per se produced little change in the number of shocks received or water consumed in controls sessions. This destruction of 5-HT neurons failed to alter the effects of PB or MQ on punished or unpunished responding. The increase in punished responding produced by the hallucinogens, however, was blocked by this destruction of 5-HT neurons. Furthermore, the capacity of the hallucinogens to decrease water intake was significantly potentiated by the neurotoxin pretreatment. These data demonstrate that the effects of the hallucinogens LSD and DOM on conditioned suppression are quite different from those of PB and MQ, and that this difference may be due to the extent of 5-HT involvement in the effects of these agents.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1983

Tolerance and cross-tolerance to central nervous system depressants after chronic pentobarbital or chronic methaqualone administration.

This study reports on tolerance and cross-tolerance to the rotarod (RR)-disrupting effects of various central nervous system (CNS) depressants. Female rats trained on the RR were fed ground chow containing pentobarbital (PB, 2.0 mg/g chow) or methaqualone (MQ, 1.0 mg/g chow) and were injected twice daily (PB) or daily MQ) with 30 mg/kg IP for 6 days. Control rats received ground chow and saline injections. On day 7 the subjects were tested with various doses of PB, MQ, diazepam (DZ), or ethanol (ET) for disruption of RR performance over the time-course of the drug effect (up to 12 hours). Control animals demonstrated a dose-dependent duration of impairment for all 4 agents. Both groups receiving chronic drug showed a prominent decrease in duration of RR impairment after PB, a less marked decrease after MQ, and even less of a decrease after DZ. However, neither chronic drug group showed an appreciable tolerance to the RR disruption of ET, relative to the control group. Based on the time of 50% recovery (RR performance recovering to 90 seconds or more), both chronic treatments resulted in a significant shift of the dose-response curves for PB, MQ and DZ to the right. Therefore, the degree of tolerance and cross-tolerance in rats chronically treated with PB or MQ was dramatic for PB and MQ, was significant for DZ, but was not demonstrable for ET.

Animals↗
PubMed1988

Sex differences in physical dependence on methaqualone in the rat.

The establishment of, and sex differences in, physical dependence on methaqualone (MQ) in rats were studied by the drug-admixed food (DAF) method. Female and male rats were treated with MQ-admixed food on the same schedule of gradually increasing doses (0.5 and 1 to 6 mg of methaqualone/g of food). Only female rats showed hypothermia from MQ at 1 and 2 mg/g and motor incoordination from MQ at 4 and 6 mg/g of food. Moreover, after MQ withdrawal, severe withdrawal signs, including convulsions and death, were observed in female rats, but not in male rats. We also instituted a different schedule of graded increases in dose (1 and 2 to 10 and 12 mg/g of food) to develop physical dependence on MQ in male rats. Under this schedule male rats exhibited a hypothermia and severe motor incoordination from MQ 6 and 8 mg/g of food condition. After MQ withdrawal, various severe signs of MQ withdrawal occurred, including tremor, convulsions and death. These results demonstrate that severe physical dependence on MQ in both sexes can be established using the DAF method, and that there are marked sex differences in the physical dependence on MQ.

Animals↗
PubMed1975

Nitrite test for methaqualone.

Details of a simple qualitative test suitable for detecting milligram quantities of methaqualone are presented. A similar reaction undergone by 2,4, 6-triaminopyrimidine suggests that the mechanism involves diazotisation of an intermediate product.

Methaqualone↗
PubMedDate not supplied

Occurrence of barbiturate, benzodiazepine, meprobamate, methaqualone and phenothiazine in car occupants killed in traffic accidents in the south of Sweden.

An investigation of the following psychoactive drugs: barbiturate, benzodiazepine, meprobamate, methaqualone and phenothiazine, was performed on all automobile occupants killed in accidents in southern Sweden during 1977 and 1978. Of 122 drivers and 55 passengers analysed, low concentrations of these drugs were found in nine drivers and in five passengers. Thus, 7.3% of the drivers were driving under the influence of drugs and, of these, two drivers (1.6% of all analysed drivers) were also inebriated. Twenty-three per cent of the drivers were inebriated only. According to the circumstances in the accidents and the number of drivers whose analyses proved positive, drug influence seldom seems to be the cause of fatal traffic accidents.

Accidents, Traffic↗
PubMed1998

Analysis of methaqualone in biological matrices by micellar electrokinetic capillary chromatography. Comparison with gas chromatography-mass spectrometry.

The analysis of methaqualone (MTQ) in biological matrices by capillary electrophoresis (CE) is described. This methods uses liquid-liquid extraction and micellar electrokinetic capillary chromatography (MECC), an operation mode of CE. Separations are made using a 25 cm long capillary and a borate/phosphate buffer at pH 8.2. Using gas chromatography with mass spectrometry detection (GC-MS) as reference method, MTQ has been analyzed in urine, blood, gastric content and hair. For hair analysis, supercritical fluid extraction was compared with liquid-liquid extraction. Linearity was established in urine and blood between 0.25 and 10.0 micrograms/ml. MTQ recovery from blood was estimated at 60%. The limit of detection of this method in urine is about 0.10 microgram/ml. Drawbacks and advantages of MECC over GC-MS are discussed.

Blood Chemical Analysis↗
PubMed1990

Receptive-field size of S1 cortical neurones is altered by methaqualone via a GABA mechanism.

Methaqualone (Mtq; quaaludes or 'ludes) is a controlled substance, having a molecular structure related to the imidiazobenzodiazepine series of drugs, that has gained some notoriety recently due to its history of widespread abuse on the street. Users report experiencing peripheral paresthesia and transient numbness on body parts receiving dense cutaneous innervation (lips, fingertips, etc.). Since the receptive-field (RF)-sizes of many primary somatosensory (S1) cortical neurones are controlled by local, gamma-aminobutyric acid (GABA)-mediated inhibitory processes, we tested Mtq to see whether its clinical symptoms might have a basis in an action through central GABA-mediated synaptic processes. This report supports this contention and describes a likely pharmacological mechanism involved as one being related to the Ro 15-1788-sensitive benzodiazepine (Bzd) recognition site(s) of the GABA receptor complex.

Animals↗
PubMedDate not supplied

Determination of methaqualone and its major metabolite in plasma and saliva after single oral doses.

A gas liquid chromatographic procedure for the determination of methaqualone and metabolite l (2-methyl-3(2-hydroxymethylphenyl)-4-(4H)-quinazoline) in plasma and saliva is described. The method requires 1.0 mL of sample and involves internal standard addition, extraction with butyl chloride, chromatography on a 1% SP-1,000 column packing using nitrogen phosphorous detectors. Within-run and day-to-day coefficient variations were less than 8% and the procedure has a sensitivity limit of 20 ng/mL. The method has been used to monitor both parent drug and metabolite in plasma and samples collected after a single oral dose.

Chromatography, Gas↗
PubMedDate not supplied

Monitoring saliva concentrations of methaqualone, codeine, secobarbital, diphenhydramine and diazepam after single oral doses.

A preliminary investigation was undertaken to determine the feasibility of monitoring saliva levels of drugs for forensic purposes. Single oral doses of the title compounds were administered to healthy volunteers. Plasma and saliva levels were measured and ratios calculated for all drugs except diazepam. Saliva/plasma ratios for methaqualone, diphenhydramine and secobarbital were all less than one and reasonably consistent between collection times and subjects. The saliva/plasma ratios for codeine were more variable, but always greater than one. Although more detailed investigation is necessary, saliva may be a useful medium for forensic monitoring of drug ingestion.

Administration, Oral↗
PubMed1982

The influence of oral contraceptives on the metabolism of methaqualone in man.

1 Oral contraceptives were shown to suppress the mid-cycle increase in methaqualone metabolism observed in premenopausal women not receiving oral contraceptive therapy. No women were identified in whom this suppression was not observed. 2 Combined oestrogen-progestogen contraceptives produced the effect in all nine women studied. The effect was also observed in one woman who was receiving progestogen-only contraceptives. 3 The effect of the combined contraceptives was observed within one month of the commencement of the contraceptive therapy. 4 The results emphasise the need to monitor the effect of the menstrual cycle in women not receiving oral contraceptive therapy when the effects of such therapy is studied. 5 These effects are more likely to be the consequence of an inhibition of hormonal control of hepatic metabolic activity by the synthetic steroids than they are to simple inhibition of hepatic metabolism.

Adult↗
PubMed1979

Deterrence of methaqualone abuse through mass urinalysis.

A temporary court-ordered cessation of urine testing in Europe and the widespread abuse of a detectable methaqualone-containing drug provided an opportunity with the resumption of testing for the evaluation of the possible effects of urinalysis on usage patterns. Evidence is presented suggesting that in this instance urinalysis acted to deter usage of this particular drug.

Humans↗