Haemodynamic effects of tiapamil and verapamil in conscious rats following chronic myocardial infarction.
The haemodynamic effects of the two calcium antagonists, tiapamil and verapamil, were compared in conscious rats with or without myocardial infarction. In control rats without myocardial infarction, verapamil was about 20 times more potent than tiapamil to reduce arterial blood pressure. However, if equihypotensive doses of tiapamil and verapamil were compared, verapamil produced a 2-fold larger decrease of dp/dtmax+ (p less than 0.01). Three weeks after myocardial infarction, the negative inotropic effect of both tiapamil and verapamil were potentiated to the same extent. However, if equihypotensive doses of tiapamil and verapamil were compared, tiapamil was still less negative inotropic than verapamil.
Pharmaceutical Research Department, F. Hoffmann-La Roche & Co., Basel, Switzerland.
J P
JP
Clozel
D000818:Animals; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D003243:Consciousness; D003864:Depression, Chemical; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009203:Myocardial Infarction / Q000188:drug therapy*; D011437:Propylamines / Q000627:therapeutic use*; D051381:Rats; D011919:Rats, Inbred Strains; D013976:Tiapamil Hydrochloride; D014700:Verapamil / Q000627:therapeutic use*
D002121:Calcium Channel Blockers; D011437:Propylamines; D014700:Verapamil; D013976:Tiapamil Hydrochloride