I hate to piss on HR but check this out:
http://www.bestbets.org/bets/bet.php?id=1007
"
These studies have found that co-intoxication with benzodiazepines is does not result in a poorer outcome. This suggests that benzodiazepine use is not implicated in the overdose. However there is evidence to suggest that benzodiazepines potentiate the effects of methadone, with several theories as to why. Despite these findings the belief that benzodiazepine use is a risk factor for overdose in the first place would discourage its use in opiate abusers.
Clinical Bottom Line
The evidence suggests that concomitant use of benzodiazepines does not result in a poorer outcome in opiate overdose. "
Unlike alcohol