VASOSELECTIVE AND DRUG-SPECIFIC EFFECTS O F ISRADIPINE ON LARGE ARTERIAL VESSELS IN HYPERTENSIVE PATIENTS COMPARED TO METOPROLOL

The effects of isradipine (Lomir(R), CAS 75695-93-1) and metoprolol (C A S 3 7350-58-6) on geometry and arterial compliance of the arteria br achialis of 14 patients each with essential hypertension were compared acutely and after three months of therapy by means of pulsed Doppler sonography and the determination of pulse wave velocity. A calculation model was used that allowed to determine the drug-specific effects on arterial diameter and compliance under isobaric conditions. Isradipin e increased measured and isobaric diameter during short-term (p < 0.05 ) and long-term administration (p < 0.05) whereas metoprolol did not c hange it. Isradipine increased measured and isobaric compliance during short-term (p < 0.05) and long-term administration (p < 0.05). Metopr olol reduced measured compliance acutely (p < 0.01) and isobaric compl iance acutely (p < 0.05) and long-term (p < 0.05). Drug-specific effec ts on compliance were different during short-term and long-term admini stration (p < 0.01); diameter was influenced differently only during s hort-term administration (p < 0.05). These opposite drug effects on th e A. brachialis are probably due to a vasoselective relaxation of smoo th muscle in large arteries by isradipine and - in the case of metopro lol - arterial constriction. The increase of arterial compliance by is radipine reduces very effectively the load on the heart and could form the basis for the improvement in the prognosis of the hypertensive pa tient.