Opioid Craving and Seeking Behavior in Physically Dependent Volunteers: Effects of Acute Withdrawal and Drug Reinforcement Opportunity.

Abstract

This study examined whether acute opioid withdrawal and drug reinforcement opportunity increase opioid craving and seeking behavior. The author used a 3 x 2 within-subject randomized crossover design to assess craving and operant behavioral effects of 3 pretreatments (naloxone 0.1 mg/70 kg, fentanyl 0.75 mg/70 kg, or saline iv) and drug or money reinforcement opportunity in 8 methadone-maintained volunteers. Each pretreatment was paired with response-contingent (15 x fixed-ratio 100) delivery of drug (fentanyl 1.5 mg/70 kg iv) and money (rated equivalent of fentanyl) in different sessions. Naloxone significantly increased opioid craving, withdrawal signs, and symptoms, but not operant behavior, relative to saline and fentanyl pretreatment. However, drug versus money reinforcement opportunity did not significantly increase opioid craving or seeking behavior.