Changes in blood pressure, plasma catecholamines and plasma renin activity during and after treatment with...

1 Tiamenidine (Hoe 440) is an imidazoline with blood pressure lowering properties. Its pharmacology resembles that of clonidine. 2 The effect of both drugs on blood pressure, plasma noradrenaline (NA), plasma adrenaline (Ad), urinary catecholamines and plasma renin activity (PRA) was assessed in four previously untreated male hypertensive patients in a cross over study. 3 The maximum daily dose of tiamenidine was 3 mg. The maximum daily dose of clonidine was 450 micrograms. 4 During treatment, blood pressure, systolic and diastolic, supine and erect, fell on average between 12 and 15%. Levels of NA, Ad, PRA were reduced during treatment. 5 During withdrawal of either drug there was rebound of blood pressure and NA, Ad, PRA, overshooting baseline levels. 6 The withdrawal effects caused by clonidine were similar for tiamenidine.