Aims To examine the literature regarding clinical pharmacokinetics, direct effects and adverse clinical outcomes associated with methamphetamine use.Methods Relevant literature was identified through a PubMed search. Additional literature was obtained from relevant books and monographs.Findings and conclusions The mean elimination half-life for methamphetamine is approximately 10 hours, with considerable inter-individual variability in pharmacokinetics. Direct effects at low-to-moderate methamphetamine doses (5–30 mg) include arousal, positive mood, cardiac stimulation and acute improvement in cognitive domains such as attention and psychomotor coordination. At higher doses used typically by illicit users (≥50 mg), methamphetamine can produce psychosis. Its hypertensive effect can produce a number of acute and chronic cardiovascular complications. Repeated use may induce neurotoxicity, associated with prolonged psychiatric symptoms, cognitive impairment and an increased risk of developing Parkinson's disease. Abrupt cessation of repeated methamphetamine use leads to a withdrawal syndrome consisting of depressed mood, anxiety and sleep disturbance. Acute withdrawal lasts typically for 7–10 days, and residual symptoms associated with neurotoxicity may persist for several months.