Abuse potential of halazepam and of diazepam in patients recently treated for acute alcohol withdrawal

Thirty men recently treated for alcohol withdrawal were enrolled in a three‐way crossover double‐blind study with a balanced incomplete block design. Patients received single doses of three of the following: halazepam, 320 mg; halazepam, 160 mg; diazepam, 40 mg; diazepam, 20 mg; and placebo. The doses of the drugs were approximately equivalent in anxiolytic effect. Patients rated themselves at baseline, 30 min after, and 1, 2, 3, 4, 6, and 8 hr after drug on the following: euphoria, sedation, “drug‐liking,” “feeling the drug,” and drug identification. By 30 min both diazepam groups reported increases in euphoria, sedation, and feeling and liking the drug; halazepam groups reported little subjective change at 30 min, and at 1 hr subjective effects did not differ from placebo on any scale. At 2 and 3 hr, both halazepam doses induced subjective effects on several scales, but peak effects were lower than peak effects of high diazepam doses. Unlike diazepam, the higher halazepam dose did not appear to induce greater effects than the lower dose. At peak, more of the diazepam group correctly identified the drug than those in the halazepam groups. More in the halazepam groups identified it as placebo than either diazepam group. To the degree that abuse potential is related to peak intensity and to time of onset of those subjective effects described as pleasant or likable, halazepam should have a lower potential for abuse than diazepam. Clinical Pharmacology and Therapeutics (1983) 34, 623–630; doi: 10.1038/clpt.1983.224