Lack of interaction between the tetracyclic antidepressant maprotiline and the centrally acting antihypertensive drug clonidine.

The well known interaction between tricyclic antidepressants and the centrally acting antihypertensive drug clonidine, namely impairment of the antihypertensive effect of clonidine, is thought to be related to blockade of noradrenaline uptake or competition at central alpha-receptors. The tetracyclic antidepressant maprotiline has been shown to be a potent inhibitor of noradrenaline uptake and it might, therefore, interfere with the antihypertensive action of clonidine. The possible interaction of clonidine and maprotiline was studied in 8 healthy subjects using doses in the therapeutic range. The study followed a double-blind, cross over design, in which clonidine alone (0.3 mg p.o.), clonidine (0.3 mg p.o.) plus maprotiline (100 mg in 4 divided doses over 22 h), maprotiline alone (100 mg in 4 divided doses over 22 h) and placebo were given by the double-dummy technique. Several pharmacodynamic parameters were measured for 12 h after administration of the drugs (supine and erect blood pressure, heart rate, saliva production and sedation). Concurrent administration of maprotiline did not alter the effect of clonidine and neither the size nor the time of the maximal response after clonidine were influenced by maprotiline. It is concluded that [1] blockade of noradrenaline uptake is not associated with the interaction of tricyclic antidepressants and clonidine, and [2] maprotiline should be preferred to tricyclic antidepressants in hypertensive patients on clonidine therapy if a concomitant depressive illness has to be treated.

RCT Entities:   Population Interventions Outcomes