INFLUENCES OF BATHING AND HOT WEATHER ON THE PHARMACOKINETICS OF A NEW TRANSDERMAL CLONIDINE, M-5041T

The influences of bathing and hot weather on plasma concentrations of clonidine were examined during application of a new transdermal clonid ine system, M-5041T, in eight healthy volunteers, An M-5041T patch con taining 6 mg of clonidine was applied on the right chest for 96 hours during winter with or without bathing (40 degrees C for 5 minutes) and also during summer without bathing, Plasma concentrations and urinary excretion of clonidine were determined for a 160-hour period after ap plication, Plasma concentrations of clonidine in the winter trials did not differ significantly with or without bathing, Plasma drug concent ration as a whole was significantly higher in the summer trial than in the winter trial, however, The maximum plasma concentration (C-max), area under the plasma concentration-time curve (AUC), and urinary excr etion (Ae) of clonidine also tended to be higher in the summer trial. These results suggest that plasma levels of clonidine are higher after application of M-5041T during hot weather. Although the period of bat hing used in this study was short, the influence of bathing seems to b e negligible.