LAUSR

tilation (p1⁄4 .0002). Our findings highly suggest that complications attributed to powder cocaine are more severe than those attributed to crack cocaine. We confirmed Euro-DEN Plus Registry data showing more frequent symptoms derived from central nervous system and cardiac hyperactivity in powder cocaine users. We observed higher methadone exposure in crackcocaine users supporting the hypothesis put forward by Mir o et al. of more frequent presumed opioid co-intoxication to explain the higher number of bradypnea episodes in their crack cocaine users. Interestingly, patients enrolled in a lowthreshold methadone maintenance treatment were also significantly more likely to report using crack cocaine than using powder cocaine [4]. The higher hospital admission rate and the longer length of stay observed in crack cocaine users referred to the emergency department in the Euro-DEN Plus Registry were attributed to their comorbidities and coexistent processes, as is well-established [5], rather than to the severity of presentation. By contrast, in our series, the longer ICU stay of powder cocaine users clearly corresponded to more marked severity. Consistent with the Euro-DEN Plus Registry, all fatalities occurred among powder cocaine users, even though we could not demonstrate a significantly higher death rate in this group. The reasons why powder cocaine use may be associated with more severe outcome remain unclear. We cannot rule out possible biases due to specific patient recruitment. However, exposure of powder cocaine users to purer cocaine and/or higher doses, resulting in higher peak concentrations may represent possible explanations as well as drug user profiles of occasional use, less chronic abuse and consequently weaker tolerance development. Nevertheless, our preliminary observations should be confirmed in larger prospective cohort studies and mechanistic investigations. Disclosure statement