Hemodynamics, biochemical effects, and pharmacokinetics of the renin inhibitor remikiren in healthy human subjects.
BACKGROUND
Remikiren (Ro 42-5892) is a potent and specific inhibitor of human renin in vitro. Its in vivo action on plasma renin activity (PRA), immunoreactive renin, and blood pressure has been shown in pilot studies in humans.


OBJECTIVE
To investigate tolerability, hemodynamic effects, and biochemical effects of remikiren in relation to its pharmacokinetics after single ascending intravenous and oral doses in healthy humans.


METHODS
In this double-blind, placebo-controlled, two-way crossover (intravenous and oral) study, single ascending doses of 10, 20, 40, 80, 160, and 320 mg (intravenous) and 100, 200, 400, 800, and 1600 mg (oral) were given; six subjects received active drug and three received placebo at each dose level. At regular intervals, blood pressure, heart rate, cardiac output, PRA, immunoreactive renin, and drug plasma levels were determined.


RESULTS
The compound was well tolerated except at the 1600 mg oral dose level at which diarrhea occurred in two subjects. At neither dose were there effects on blood pressure, heart rate, or cardiac output relative to placebo. PRA and angiotensin I production rate decreased and immunoreactive renin increased dose dependently after both intravenous and oral administration. The duration of these effects was also dose dependent and was longer than 12 hours with higher doses. Systemic plasma clearance, volume of distribution, and absolute bioavailability of remikiren were in the magnitude of 900 ml/min, 70 L, and below 1%, respectively. The angiotensin I production rate correlated in a sigmoidal way with plasma drug concentrations independent of the route of administration.


CONCLUSIONS
Remikiren is a potent inhibitor of renin in humans with long-lasting effects after both intravenous and oral administration.
Kleinbloesem
C H
CH
F. Hoffmann-La Roche Ltd., Basel, Switzerland.
Weber
C
C
Fahrner
E
E
Dellenbach
M
M
Welker
H
H
Schröter
V
V
Belz
G G
GG
D000284:Administration, Oral; D000328:Adult; D000803:Angiotensin I / Q000187:drug effects; D001682:Biological Availability; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007093:Imidazoles / Q000493:pharmacokinetics / Q000494:pharmacology*; D007275:Injections, Intravenous; D008297:Male; D008954:Models, Biological; D012016:Reference Values; D000092502:Renin Inhibitors
D000803:Angiotensin I; D007093:Imidazoles; D000092502:Renin Inhibitors; C065581:remikiren