Effect of diphenhydramine on methaqualone metabolism: an in vitro study

Effects of Mandrax and Cannabis on the cellular function of chick embryonic neurons

Cannabis and Mandrax abuse is unique to South Africa; and most research has focused on the socio-economic impact rather than the adverse effects on the developing brain. Therefore, the aim of this study is to determine the effects of Mandrax and Cannabis alone and in combination on the developing brain by using primary and suspension cultures of the chick embryo brain. Exposure of primary chick embryo neuronal (CEN) cultures to the carrier ethanol, Mandrax and Cannabis, for 24h resulted in a significant dose dependent decrease in cell number for Mandarx alone. Increasing concentrations of Cannabis in combination with Mandrax inhibited the toxic effect of Mandrax. In CEN suspensions, Mandrax alone induced a significant time-concentration dependent decrease in esterase activity following 1 and 4h exposure. In combination with Cannabis, a significant increase in esterase activity was observed after 4h exposure. In conclusion Mandrax is toxic to CEN cells in vitro while Cannabis seemed to have a protective effect; however, this study does not investigate the abuse of these drugs in the form commonly abused, namely inhaled smoke.

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.

Clinical symptomatology of diphenhydramine overdose: an evaluation of 136 cases in 1982 to 1985

In West Germany, the antihistaminic diphenhydramine is marketed as a non-prescription hypnotic. Results of toxicological screening in cases of drug overdose indicate that poisoning with diphenhydramine represents a substantial part (4.5%) of the total number of intoxications. A total of 136 cases of diphenhydramine poisoning in 1982-1985 were evaluated with respect to age, ingested dose, plasma level, and clinical symptomatology. All patients had taken diphenhydramine with suicidal intent. Two-thirds of the patients were aged 14-30 years. In about 50% of the cases, between 6 and 40 times a therapeutic dose was ingested. Diphenhydramine plasma levels showed a wide range (0.1-4.7/micrograms/ml) due to differences in ingested dose and time between ingestion and admission to hospital. Impaired consciousness was the most common symptom. Psychotic behavior similar to catatonic stupor--often combined with anxiety--was highly specific for diphenhydramine poisoning. Further symptoms included hallucinations, mydriasis, tachycardia, and less frequently diplopia, respiratory insufficiency, and seizures. Primary treatment included gastric lavage, administration of activated charcoal and sodium sulfate. In one case, hemodialysis and ultrafiltration were performed which had only limited effect on diphenhydramine plasma elimination kinetics. This patient died of diphenhydramine overdose and extreme hypothermia. All intoxications except the one mentioned before had an uncomplicated clinical course. In vitro experiments indicate that diphenhydramine may be almost completely removed from the plasma compartment by hemoperfusion. Routine analysis of urine samples in diphenhydramine overdose led to the identification of 4 previously unknown metabolites and artifacts of diphenhydramine.

Doxylamine metabolism in rat and monkey

Metabolites of doxylamine obtained with rat-liver homogenate in vitro and from urine of Wistar rats and squirrel monkeys in vivo were examined. The metabolites were separated by g.l.c., h.p.l.c. and t.l.c., and tentatively identified through interpretation of their mass-spectrometric behaviour. N-Desmethyldoxylamine was identified in vitro while both N-desmethyl and N,N-didesmethyldoxylamine were detected in rat and monkey urine. The N-acetyl conjugates of N-desmethyl and N,N-didesmethyldoxylamine were tentatively identified both in rat urine and in vitro. Only the N-acetyl conjugate of N,N-didesmethyldoxylamine was detected in monkey urine. In addition, nine other metabolites were tentatively identified in rat urine: N,N-dimethyl-2-[1-(?-hydroxyphenyl)-1-(2-pyridyl)ethoxy]ethanamine; N-methyl-2-[1-(?-hydroxyphenyl)-1-(2-pyridyl)ethoxy]ethanamine; 1-phenyl-1-(2-pyridyl)ethanol; 1-(?-hydroxyphenyl)-1-(2-pyridyl)ethanol; 1-phenyl-1-(2-pyridyl)ethane; 1-(?-hydroxyphenyl)-1-(2-pyridyl)ethane; 2-phenyl-2-(2-pyridyl)ethanol; N,N-dimethyl-2-[1-phenyl-1-(2-pyridyl)-2-hydroxyethoxy]ethanamine; doxylamine pyridine N-oxide. The excretion of doxylamine aliphatic N-oxide in rat urine was confirmed by comparison with the authentic synthetic compound.

Methaqualone-diphenhydramine interaction study in humans

Twelve healthy subjects received three single oral doses (250 mg) of methaqualone alone or in combination with diphenhydramine (25 mg). Blood samples were collected for a 48-hr period after each dose and analyzed for methaqualone and its major metabolite, 2-methyl-3-(2'-hydroxymethylphenyl)-4(3H)-quinazolinone. Peak blood concentrations ranging from 1.0 to 2.7 micrograms/ml occurred approximately 1-2 hr after the oral dose. The area under the blood level-time curve, peak plasma level, and elimination half-life for methaqualone were not significantly different (three-way ANOVA, p greater than 0.05) when methaqualone was administered alone, in combination with a diphenhydramine elixir or as a commercial product (capsule) containing both methaqualone and diphenhydramine. Statistically significant intersubject differences in the area under the curve were eliminated if the area was corrected for subject differences in elimination. Blood levels of the metabolite reached an average peak of 314 ng/ml (+/- 107) between 4 and 8 hr after the dose and remained elevated for the 48-hr sampling period. The areas under the blood level time curve of the metabolite were not significantly different for the three treatments. Diphenhydramine administered at the dosage level used in therapeutic combination products did not alter the blood levels of methaqualone or its metabolite. In addition, no significant differences in methaqualone availability from the two commercial formulations tested could be detected.