EFFECT OF ERYTHROMYCIN ON ETHANOLS PHARMACOKINETICS AND PERCEPTION OFINTOXICATION

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. Tw elve blood samples were obtained over a 12-hour period to determine et hanol concentrations. Perception of intoxication was determined at eac h time point using a 10-cm visual analog scale. Ethanol concentrations were determined using a gas chromatographic method. Mean +/- SD ethan ol pharmacokinetics for erythromycin versus placebo were time to peak ethanol plasma concentrations 1.1 +/- 0.4 hours versus 1.3 +/- 0.3 hou rs, 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 vers us 465 +/- 132 mg . hour/dl (p>0.05). The blood ethanol concentrations and perception of intoxication scores on a visual analog scale were w ell correlated (r(2)=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/hou r for erythromycin and placebo, respectively (p>0.05). Conclusion. Ora l erythromycin base 1500 mg/day compared with placebo does not alter e thanol's pharmacokinetics or perception of intoxication in healthy vol unteers.