Prevalence of Dependence

Dependence on barbiturates has declined in recent years as physicians have substituted benzodiazepines for the treatment of many of the conditions for which barbiturates were formerly used. Clinicians will still see cases of abuse and dependence among medical patients receiving barbiturates or barbirurate combination products (e.g., Fiorinal) and in substance abusers (Silberstein and McCrory 2001). 

Charney et al. (2001), Harvey (1985), Matthew (1971), and Wesson and Smith (1977) have discussed the pharmacology of barbiturates. Barbiturates are derived from barbituric acid, which is the product of the fusion of malonic acid and urea. Barbituric acid lacks CNS activity. The two main classes of barbiturates are the highly lipid-soluble thiobarbiturates, in which sulfur replaces oxygen at the second carbon atom of the barbituric acid ring, and the less soluble oxybarbiturates, with oxygen at the second carbon atom (Table 3-3). Highly lipid-soluble barbiturates have a more rapid onset, a short duration of action, and greater potency than those with lower lipid solubility. 

Duration of action Generic name Brand name(s) 

Intermediate acting Amobarbital Amytal, Tuinal (with secobarbital) 

Long acting (12—24 Phenobarbital Luminal and many combination 

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