A certain amount of cross-tolerance exists among these drugs, and chronic users of barbiturates are generally quite resistant to many of the effects of alcohol, minor tranquillizers and volatile anaesthetics, as well. In addition, the sedative drugs have the capacity to be substituted for each other in diminishing withdrawal symptoms, and barbiturates are frequently used therapeutically to reduce the severity of withdrawal in alcoholics. Since the sedatives show this cross-dependence, individuals dependent on one may turn to other sedatives if the supply of the preferred drug is restricted. Consequently, chronic barbiturate dependents are usually heavy alcohol users as well. Such multiple users often refer to the barbiturate intoxication as a 'dry drunk'.
Barbiturates have the advantage of producing inebriation without the obvious odour of alcohol.
The relationship between barbiturates and the opiate narcotics is more complicated. These drugs may not show significant cross-tolerance, although barbiturates can be useful in the treatment of opiate narcotic withdrawal symptoms and may effectively reduce the unpleasantness of the abstinence syndrome. The drugs do interact in some sort of complementary way since barbiturates are frequently, used by opiate narcotic dependents to strengthen or reinforce a weak heroin dose or as a substitute in an emergency. Many opiate users, however, avoid barbiturates and consider the barbiturate-dependent person to be at the bottom of the 'addict' community, together with the alcoholics. Barbiturates are often used in conjunction with amphetamines.