"A first priority for prevention must be to reduce the frequency of drug overdoses. We should inform heroin users about the risks of combining heroin with alcohol and other depressant drugs. Not all users will act on such information, but if there are similar behavioral changes to those that occurred with needle-sharing overdose deaths could be substantially reduced. Heroin users should also be discouraged from injecting alone and thereby denying themselves assistance in the event of an overdose."

Source

Wayne D. Hall, PhD, "How can we reduce heroin 'overdose' deaths?" The Medical Journal of Australia (MJA 1996; 164:197).