Acute inotropic effects of intravenous nifedipine and its vehicle compared with saline: a double-blind study of systolic time intervals in normal subjects.
1. The inotropic effects of intravenous nifedipine and its vehicle were studied noninvasively in a double-blind placebo controlled crossover fashion using systolic time intervals in 12 normal subjects. 2. Nifedipine caused vasodilation, a fall in systolic and diastolic blood pressure, and increased heart rate. The vehicle alone caused vasodilation and decreased systolic blood pressure, without a change in heart rate. 3. Nifedipine increased left ventricular ejection time (LVET) and decreased pre-ejection period (PEP) and the ratio PEP/LVET, whereas the vehicle alone had the opposite effect. Neither treatment affected the total duration of electromechanical systole. 4. These results suggest that the vehicle has a negative inotropic effect, which is overcome by the indirect positive inotropic effect of nifedipine when they are administered together systemically.
Walley
T J
TJ
Department of Pharmacology and Therapeutics, University of Leicester.
Heagerty
A M
AM
Woods
K L
KL
Bing
R F
RF
Pohl
J E
JE
Barnett
D B
DB
D000328:Adult; D004311:Double-Blind Method; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D009543:Nifedipine / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D014677:Pharmaceutical Vehicles / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D013268:Stimulation, Chemical; D013599:Systole / Q000187:drug effects*
D014677:Pharmaceutical Vehicles; D012965:Sodium Chloride; D009543:Nifedipine