Effects of pergolide on intravenous cocaine self-administration in men and women

Abstract

Clinical evidence suggests that pergolide, a D₁/D₂ dopamine receptor agonist, may be useful in maintaining cocaine abstinence. We investigated pergolide’s effects in a laboratory model of IV cocaine self-administration by humans. Twelve inpatient volunteers (7M, 5F), who reported spending an average of $170/ week on cocaine, received pergolide (0.05 mg BID) for 8 days and placebo for 8 days, with drug order balanced across subjects. Self-administration sessions occurred on the last 4 days of maintenance on each medication. A modified seven-trial progressive ratio choice procedure (0, 8, 16, 32 mg/70 kg cocaine versus $5) was utilized, with sessions consisting of: (a) two sample trials, where participants responded to receive the dose and tokens available that day, and (b) five choice trials, where participants chose between the available dose and tokens. Following each trial, the response requirement for the chosen option increased by 400. Maintenance on pergolide 1) decreased cocaine-induced increases in ratings of “High,”“Stimulated,” cocaine “Potency,” estimates of street value, and heart rate, 2) increased ratings of “I want cocaine,” and 3) had no effect on cocaine self-administration. The increased desire to use cocaine during pergolide maintenance suggests that it has limited treatment utility at this dose, but given the attenuation of cocaine’s subjective and cardiovascular effects, an investigation of a wider range of pergolide doses on cocaine self-administration and subjective effects is warranted.