Effect of erythromycin on ethanol's pharmacokinetics and perception of intoxication.

STUDY OBJECTIVE

To determine the effect of erythromycin on ethanol's pharmacokinetics and perception of intoxication.

DESIGN

Double-blind, randomized, placebo-controlled, crossover study.

SETTING

A clinical research center.

PARTICIPANTS

Ten healthy volunteers.

INTERVENTIONS

Erythromycin base 500 mg or identical placebo was administered 3 times/day for 7 days. On day 8, ethanol 0.8 g/kg was administered by mouth concurrently with erythromycin or placebo. A 2-week washout period was allowed between each treatment arm.

MEASUREMENTS AND MAIN RESULTS

Twelve blood samples were obtained over a 12-hour period to determine ethanol concentrations. Perception of intoxication was determined at each time point using a 10-cm visual analog scale. Ethanol concentrations were determined using a gas chromatographic method. Mean +/- SD ethanol pharmacokinetics for erythromycin versus placebo were time to peak ethanol plasma concentrations 1.1 +/- 0.4 hours versus 1.3 +/- 0.3 hours, peak ethanol concentrations 118 +/- 18 mg/dl versus 114 +/- 27 mg/dl, ethanol oral clearance (CL/F) 2.9 +/- 0.8 ml/min/kg versus 3.4 +/- 2.2 ml/min/kg, and area under the curve 481 +/- 104 mg.hour/dl versus 465 +/- 132 mg.hour/dl (p > 0.05). The blood ethanol concentrations and perception of intoxication scores on a visual analog scale were well correlated (r2 = 0.78, p < 0.01). Mean +/- SD areas under the effect versus time curve were 35.1 +/- 20.7 cm/hour and 31.5 +/- 18.2 cm/hour for erythromycin and placebo, respectively (p > 0.05).

CONCLUSION

Oral erythromycin base 1500 mg/day compared with placebo does not alter ethanol's pharmacokinetics or perception of intoxication in healthy volunteers.