SUBJECTIVE, BEHAVIORAL, AND PHYSIOLOGICAL-RESPONSES TO INTRAVENOUS DEZOCINE IN HEALTHY-VOLUNTEERS

Dezocine is an agonist-antagonist opiate that acts at the mu receptor, and is used for management of pain. Monkeys will readily press a leve r to receive an injection of dezocine, and in former opiate addicts de zocine produces positive subjective effects similar to those of morphi ne. It is not clear, however, what its subjective effects are in peopl e who do not have a history of opiate abuse. To answer this question, a within-subjects design was used in which 10 normal healthy volunteer s (six men, four women) were injected with 0, 2.5, 5.0, and 10 mg/70 k g of dezocine in a double-blind fashion. Subjects completed several qu estionnaires (e.g., Addiction Research Center Inventory) commonly used in abuse liability testing before and at periodic intervals for up to 5 h after drug injection. We also assessed psychomotor performance (e .g., eye-hand coordination) and several physiologic measures (e.g., pu pil size, respiration rate) at these times. Dezocine produced increase s in ratings of drug liking (P < 0.001), as well as other subjective e ffects that might be considered as pleasant ("good mood," "drunken," " coasting," "happy" ratings) (all P < 0.05). At the same time, the drug had effects (increased dysphoria and sedation) that typically are not reported by addicts. Dezocine produced psychomotor impairment and mio sis (constriction of the pupils) in a dose-dependent fashion. The obse rvation that dezocine produces euphoria and increased drug-liking rati ngs in individuals without histories of drug abuse suggests that hospi tals and surgicenters should have strict accountability procedures wit h this drug.