Systemic and renal hemodynamic effects of single oral doses of felodipine in patients with refractory hypertension receiving chronic therapy with beta-blockers and diuretics.
In 12 patients with primary hypertension (World Health Organization stage 2) inadequately controlled by chronic standard triple therapy, hydralazine was replaced by felodipine, a new vasodilating dihydropyridine derivative, and the acute effects of the drug on central and renal hemodynamics were monitored. Following baseline measurements, an oral solution of felodipine (0.075-0.1 mg/kg) was given. Fifteen minutes after intake of felodipine, a significant hypotensive response was observed, and the maximal response (23% reduction of mean arterial pressure) occurred after 30 min. There was a linear relationship between the changes in mean arterial pressure and log plasma concentration of felodipine. Cardiac output (dye dilution) increased during maximal blood pressure reduction, from 5.3 +/- 1.0 to 6.6 +/- 2.4 L/min (p less than 0.01), partly because of increased heart rate from 57 +/- 4 to 65 +/- 9.1 beats/min (p less than 0.01) and partly because of increased stroke volume from 93 +/- 14 to 104 +/- 33 ml (p less than 0.05). Renal plasma flow (para-aminohippuric acid clearance) increased significantly (p less than 0.05) from 343 +/- 138 to 391 +/- 154 ml/min, while glomerular filtration rate ([51Cr]EDTA clearance) did not change. Arteriovenous noradrenaline difference increased 36% during felodipine therapy, when corrected for blood flow increase. We conclude that felodipine is a calcium inhibitor with potent vasodilating properties.
Andersson
O K
OK
Granérus
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G
Hedner
T
T
Wysocki
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M
D000284:Administration, Oral; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D015736:Felodipine; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007668:Kidney / Q000098:blood supply*; D008297:Male; D009543:Nifedipine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D009638:Norepinephrine / Q000097:blood; D012083:Renin / Q000097:blood; D014655:Vascular Resistance / Q000187:drug effects
D000319:Adrenergic beta-Antagonists; D012083:Renin; D009543:Nifedipine; D015736:Felodipine; D009638:Norepinephrine