Acute haemodynamic effects of a single intravenous dose of piretanide in congestive heart failure.

The haemodynamic effect of a single 12 mg intravenous dose of piretanide was assessed in 11 patients with congestive heart failure. It did not cause any change in cardiac output, heart rate or systemic vascular resistance, whereas the pulmonary wedge, mean pulmonary and right atrial pressures and pulmonary blood volume fell progressively, the difference from the control values being significant 5 minutes after the injection. The temporal evolution of the ratios pulmonary wedge pressure/total blood volume, pulmonary blood volume/total blood volume, right atrial pressure/total blood volume was chiefly determined by the numerator, which in all cases showed a more rapid decrease than total blood volume. Serum electrolytes remained unchanged 1 hour after the injection of the drug, except for potassium which fell from 4.9 to 4.1 mEq/l, while urinary sodium and potassium excretion were greatly increased. This high ceiling diuretic appears to have renal and venodilator properties close to those of furosemide.