Intravenous Use of Prescription Psychostimulants; A Comparison of the Pattern and Subjective Experience between Different Methylphenidate Preparations, Amphetamine and Cocaine.

Background/aims: Methylphenidate (MPH) has been the most commonly used intravenous (i.v.) substance in Iceland in recent years. In Iceland, MPH is available in 3 forms: immediate-release (IR) tablets (MPH IR, short-acting), sustainable-release (SR) capsules (MPH SR, long-acting) and osmotic-release (OROS) tablets (MPH OROS, long-acting). The aims of the study were to compare the pattern and subjective effects of i.v. MPH use to other i.v. psychostimulants and examine whether the pattern of use differs among MPH preparations.

Methods: This is a nationwide descriptive study. Information was collected from 95 i.v. substance users undergoing inpatient detoxification and reporting i.v. MPH use in the last 30 days using a semi-structured interview.

Results: MPH SR was both the most commonly used (96%) and preferred i.v. psychostimulant (57%). The intensity and duration of 'euphoria' did not differ between cocaine and MPH SR. No participant reported MPH OROS as their preferred substance even though a third had used it in the past month.

Conclusions: The pattern of i.v. MPH use is similar to other psychostimulants among treatment seeking patients. MPH OROS was the least preferred i.v. psychostimulant, despite having the largest market share in Iceland. The results indicate that MPH OROS has less abuse potential than other MPH preparations.