Effects of high-dose heroin versus morphine in intravenous drug users: A randomised double-blind crossover study?

The purpose of this study is to evaluate the effects of high doses of injec ted opiates as prescribed maintenance in intravenous drugs users. This was accomplished via a randomised double-blind study with crossover at an outpa tient clinic in Bern, Switzerland. The subjects were 39 patients with a lon g history of intravenous opioid use and persistent abuse despite treatment; they were randomly allocated to two groups. Group A was started on control led injection of graduated doses of morphine up to a satisfying individual dose and was then switched as a double blind to heroin at a randomly determ ined day between week three and four. Subsequently this group was given her oin for the remaining two to three weeks of the study. Group B was started on heroin and was then switched to morphine in the same manner. Equipotent solutions of 3% morphine and 2% heroin were administered. The main outcome measures were clinical observations, structural interviews and self report of subjective experiences to assess the effects of the drugs. In 16 cases, the study had to be discontinued owing to severe morphine-induced histamine reactions. Thirteen participants in Group B presented these adverse reacti ons on the day of the switch-over, Full data were thus only obtainable for 17 participants. Average daily doses were 491 mg for heroin and 597 mg for morphine. The findings indicate that heroin significantly produced a lower grade of itching, flushing, urticaria and pain/nausea. A negative correlati on between dose and euphoria was observed for both heroin and morphine. The authors concluded that as heroin produces fewer side effects it is the pre ferred high-dose maintenance prescription to morphine. The perceived euphor ic effects are limited in both substances.