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.