Pharmacokinetic properties of 4-fluoroamphetamine in serum and oral fluid after oral ingestion.

Abstract

Each year, synthetic drugs occur in high numbers on the illicit drug market. But data on their pharmacology and toxicology are scarce. Therefore, a controlled study was performed to evaluate pharmacokinetic parameters of 4-fluoroamphetamine (4-FA) in humans and to compare it with effects. Twelve subjects ingested 100mg and five subjects also received 150mg 4-FA in a bitter lemon drink. Blood and oral fluid samples were taken during the following 12hours and analyzed for 4-FA and traces of amphetamine as impurity by liquid chromatography-tandem mass spectrometry (LC-MS/MS). For 12hours after ingestion, the concentration-time course of 4-FA was similar to that of amphetamine with maximal concentrations appearing in serum after about 2hours (in median 195ng/mL after the 100mg dose, range 155-316ng/mL). The elimination half-life was approximately 8-9hours and shorter than that of amphetamine but it exhibited a marked variation (5.5-16.8hours). In oral fluid, 4-FA could also be detected for 12hours and concentrations were higher than in serum. During the first 3hours after ingestion concentrations were higher, most probably due to oral contamination. Serum concentrations in forensic cases were in the range of those observed in the present study suggesting dosages in recreational use in the range of those tested here. The pharmacokinetic properties of 4-FA are similar to that of amphetamine including a marked variation in elimination. However, recreational dosages may already exhibit prominent adverse effects and may even have life-threatening consequences.