Background Methamphetamine-related harms have been increasing in Melbourne, Australia, yet little is known of how users interact with the drug market. We describe methamphetamine purchases and use as reported by a Melbourne-based cohort of people who inject drugs (PWID). Methods A total of 2862 interviews from 757 participants of the Melbourne Injecting Drug User Cohort Study between April 2008 and February 2015 were used to generate descriptive statistics for the: size, search time and setting (e.g. house, street) of methamphetamine purchases, and the percentage that were shared; and the time of day, time between purchasing and using and setting of methamphetamine use. Results No meaningful differences were observed between the powder and crystal methamphetamine markets. The most frequently purchased amount of methamphetamine was $100 with much larger transactions common; however 42% of purchases were shared, most commonly 50/50 with a partner or friend. The median time to obtain methamphetamine was 20 minutes (interquartile range (IQR) 5–30 minutes) and the median time between purchasing and using methamphetamine was 5 minutes (IQR 5–10 minutes). Most purchases were used between 10 am and 2 pm (43% of purchases), but 33% were used outside of business hours. Both purchasing and using methamphetamine occurred more frequently in houses than public settings. Conclusions It was common for PWID in our sample to obtain 4$100 of methamphetamine with a partner or friend, with relatively little search time. Support services for methamphetamine users may need to increase their operating hours to adapt to the large amount of use occurring outside of business hours.

This work was supported by the National Drug Law Enforcement Research Fund [NDLERF 2012/13-13]. The Melbourne Injecting Drug User Cohort Study is funded through National Health and Medical Research Council grants and untied philanthropic contributions. NS is the recipient of a Burnet Institute Jim and Margaret Beever Fellowship and PD is the recipient of a National Health and Medical Research Council (NHMRC) Senior Research Fellowship. The authors gratefully acknowledge the contribution to this work of the Victorian Operational Infrastructure Support Program.