Potentiation of antihypertensive effect of clonidine by ACE inhibitors can be clinically useful.(See reference number 1) However, limited evidence suggests that effects of captopril may be delayed when patientsare switched from clonidine.(See reference number 2) Note that sudden withdrawal of clonidine may cause rebound hypertension.
Catapres Tablets (Clonidine hydrochloride). Boehringer Ingelheim Ltd. UK Summary of product characteristics,May 2006.
Gröne H-J,Kirchertz EJ, Rieger J. Mögliche Komplikationen und Probleme der Captopriltherapie bei Hypertonikern mit ausgeprägten Gefäßschäden. Therapiewoche (1981) 31, 5280–7.