The metabolism of amphetamine in dependent subjects.

Abstract

The metabolism of (+)-[14C] amphetamine has been studied in two women who had been taking 90–100 mg of Dexedrine ((+)amphetamine sulphate; Smith, Kline & French) daily for several years but who showed no evidence of overt amphetamine toxicity. The urinary metabolites were identified, estimated and compared with the results previously obtained from two drug naive male subjects who had received 20 mg of (±)amphetamine (Caldwellet al., (1972b). The same metabolites were found, but the dependent subjects excreted in 24 h more unchanged amphetamine (about 30% of dose) than the naive subjects (20%). This may be a reflection of the dose, which in dependent subjects was five times that of naive subjects. The dependent subjects excreted in 24 h slightly more norephedrine (2.9, 4.1% of dose) and 4′-hydroxynorephedrine (1.1, 1.6%) than the naive subjects (norephedrine, 2.2, 2.6%; 4′-hydroxynorephedrine, 0.3, 0.4%), but the difference in percentage of dose may not be significant. However, in absolute terms the dependent subjects are producing at least five times as much norephedrines as the naive subjects because of the larger dose.