Effects of heroin self-administration on cigarette smoking.

Cigarette smoking increased during heroin self-administration in comparison to drug-free and methadone detoxification conditions in eight heroin addicts given naltrexone placebo (P less than 0.01) and three heroin addicts given buprenorphine placebo. Cigarette smoking was stable across conditions for one subject who did not use heroin during naltrexone blockade of heroin effects. Five subjects smoked significantly more (P less than 0.01) during the hour following a heroin injection than during the preceding hour, and two subjects in the same group smoked significantly less following a heroin injection (P less than 0.05). Subjects smoked significantly more during the evening and night when self-administering heroin than during baseline conditions (P less than 0.05), but subjects did not sleep significantly less during heroin self-administration. The peak of the intercigarette interval distribution remained between 16-30 min during baseline and heroin conditions. However, the increased smoking during heroin use appeared to reflect a higher rate of smoking rather than a generalized increase across intercigarette intervals. These data extend previous findings, that alcohol consumption is associated with increased cigarette smoking, to IV heroin self-administration.