Methaqualone
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Mechanism of action
IN ADDITION TO SEDATIVE-HYPNOTIC PROPERTIES ... /IT/ POSSESSES ANTICONVULSANT, ANTISPASMODIC, LOCAL ANESTHETIC, & WEAK ANTIHISTAMINIC PROPERTIES. IN HIGH DOSES IT SELECTIVELY DEPRESSES POLYSYNAPTIC PATHWAYS IN THE SPINAL CORD. THE DRUG HAS ANTITUSSIVE ACTIVITY COMPARABLE TO THAT OF CODEINE ... IT LACKS ANALGESIC ACTIVITY.
Pharmacokinetics
Half-life
2-3 hr /From table/
Absorption
IN MAN, 99% OF METHAQUALONE IS ABSORBED IN 2 HOURS. IN THE PLASMA, 70 TO 90% IS BOUND TO ALBUMIN. ... METABOLITES ... ARE MAINLY CONJUGATED AND EXCRETED IN THE URINE, BUT THE 4-HYDROXY METABOLITE IS EXCRETED INTO BILE. THE PHARMACOKINETICS IS THAT OF A TWO-COMPARTMENT SYSTEM, WITH A DISTRIBUTION HALF-LIFE OF LESS THAN 1 HOUR AND AN ELIMINATION HALF-LIFE OF 10 TO 40 HOURS.
AFTER ABSORPTION METHAQUALONE IS TAKEN UP BY ADIPOSE TISSUE & GRADUALLY RELEASED OVER PERIOD OF SEVERAL DAYS. AS IT IS RELEASED IT RAPIDLY UNDERGOES GLUCURONIDE CONJUGATION ... & IS EXCRETED EQUALLY IN URINE & FECES FOR UP TO 6-7 DAYS. IN TOXIC DOSES UNMETABOLIZED METHAQUALONE IS ALSO FOUND IN URINE.
BLOOD & URINE SAMPLES FROM ACUTELY INTOXICATED PATIENT STUDIED. 4 MAJOR MONOHYDROXYLATED METABOLITES FOUND CONJUGATED IN URINE. 2-METHYL-3-[2-(HYDROXYMETHYL)PHENYL]-4(3H)-QUINAZOLINONE FOUND UNCONJUGATED IN URINE & BLOOD.
URINARY EXCRETION OF 5 C-MONOHYDROXY METABOLITES & METHAQUALONE N-OXIDE MEASURED FOLLOWING ORAL ADMIN OF 250 MG TO GERIATRIC PT. TOTAL EXCRETION OF 6 METABOLITES IN 24 HR WAS APPROX ONE-HALF THAT IN GROUP OF YOUNG, HEALTHY ADULTS.
For more Absorption, Distribution and Excretion (Complete) data for METHAQUALONE (10 total), please visit the HSDB record page.
Metabolism
MORE THAN 99% OF THE DRUG IS METABOLIZED BY THE HEPATIC MICROSOMAL SYSTEM, AND 4-HYDROXYMETHAQUALONE AND THE N'-OXIDE ARE THE MAJOR PRIMARY METABOLITES. AT LEAST EIGHT OTHER HYDROXYL METABOLITES ARE FORMED.
YIELDS 3-(3-HYDROXY-2-METHYLPHENYL)-2-METHYL-4(3H)-QUINAZOLINONE, 3-(4-HYDROXY-2-METHYLPHENYL)-2-METHYL-4(3H)-QUINAZOLINONE, & 6-HYDROXY-2-METHYL-3-(O-TOLYL)-4(3H)-QUINAZOLINONE IN MAN. /FROM TABLE/
... METHAQUALONE ... GAVE 2-NITROBENZO-ORTHO-TOLUIDIDE ... AS HUMAN URINARY METABOLITE.
BIOTRANSFORMATION ... WOULD BE EXPECTED TO PROCEED BY HYDROXYLATION, & THIS LARGELY OCCURS IN PRACTICE, WHEN GLUCURONIDES OF ... 2-METHYL-3-(3-HYDROXY-2-METHYLPHENYL)-4(3H)-QUINAZOLINONE, 2-METHYL-3-O-TOLYL-6-HYDROXY-4(3H)-QUINAZOLINONE & 2-METHYL-3-O-TOLYL-8-HYDROXY-4(3H)-QUINAZOLINONE ... EXCRETED IN URINE OF ... RATS.
For more Metabolism/Metabolites (Complete) data for METHAQUALONE (7 total), please visit the HSDB record page.
Methaqualone has known human metabolites that include hydroxy-methaqualone.
External links
Fact-sheets from PsychonautWiki. Harm-reduction reference only — not medical advice.