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

Meperidine is a mu opiate agonist that is frequently used to treat pai n. We examined in healthy volunteers (N = 10) the effects of intraveno us meperidine (0, 0.25, 0.5, and 1.0 mg/kg) on mood and psychomotor pe rformance. A randomized, placebo-controlled, crossover design was used in which subjects were injected with meperidine or saline in a double -blind fashion. Subjects completed several subjective effects question naires commonly used in abuse liability testing studies before drug in jection and at periodic intervals for up to 5 h after drug injection. Subjects also completed several psychomotor tests. Meperidine produced a constellation of subjective effects in a dose-related fashion, incl uding increases in ratings of ''sedated,'' ''coasting or spaced out'' and ''feel drug effect'' ratings. Many of the drug's subjective effect s persisted up to 4 or 5 h after administration of the 1.0 mg/kg dose. Drug liking ratings assessed on a visual analog scale were increased after meperidine injection in about half of the subjects (P = 0.09). E ye-hand coordination was affected slightly by meperidine but other ind ices of psychomotor functioning were unaffected. Miosis increased in a dose-related fashion. Other physiological parameters, such as vital s igns, were not affected by meperidine. We conclude that meperidine in healthy volunteers has robust and long-lasting effects on mood, but ma y have weaker effects on psychomotor performance.