The effects of clonidine treatment on alcohol intake during the daily 2-h free-choice between alcohol and water in the 5-day treatment trial are presented in Fig. 3. Pre-drug alcohol intake was determined on a Friday, drug days 1–5 occurred on Monday–Friday, and the 2 post-drug days occurred on the Monday and Tuesday following termination of drug treatment. There was no significant difference in alcohol intake among treatment groups on the pre-drug day. During the 5 treatment days there was a significant effect of dose [F(4,46) = 22.18, p < 0.001] and a significant effect of day [F(4,184) = 3.36, p < 0.05] on alcohol intake, but no significant dose × day interaction. Pairwise comparisons using the Fisher’s LSD test revealed that alcohol intake was decreased (p < 0.001), independent of day, by clonidine at doses of 40 or 80 µg/kg relative to treatment with vehicle, independent of day. Alcohol intake was decreased (p < 0.05) by treatment with clonidine 80 µg/kg relative to treatment with clonidine 40 µg/kg. On post-treatment days 3 and 4, there were no significant effects of dose or day on alcohol intake and no significant dose × day interaction.
