Hemodynamic side effects of trypanocidal diamidines in rats. Studies on possible antagonisms.

The influence of the alpha-receptor agonist oxymetazoline, the antihistaminics mepyramine and cimetidine and of cromoglicic acid disodium salt (disodium cromoglycate, DSCG) on the hypotension produced by the trypanocidal diamidines pentamidine, diamidinophenylindole (DAPI) and diimidazolinophenylindole (DIPI) was investigated. 75-100 nmol/kg oxymetazoline were effective only in DAPI-treated animals and diminished the drop of the systolic blood pressure by 25-49%. Pretreatment with DSCG was ineffective in all groups under the conditions used. Preapplication of a combination of 5 mumol/kg mepyramine and 10 mumol/kg cimetidine was effective only in pentamidine-treated animals and reduced the drop of the systolic pressure by 57%.