Effects of piretanide in normal subjects

Area of Science:

• Pharmacology
• Nephrology
• Clinical Therapeutics

Background:

• Piretanide is a novel loop diuretic.
• It exhibits pharmacologic properties similar to furosemide.
• Piretanide is approximately six times more potent than furosemide.

Purpose of the Study:

• To assess the pharmacokinetics and pharmacodynamics of oral piretanide.
• To compare the potency of piretanide with furosemide and bumetanide at the tubular level.

Main Methods:

• 21 healthy subjects received oral doses of 3, 6, or 12 mg of piretanide.
• Serial blood and urine samples were collected to analyze drug kinetics and dynamics.
• The relationship between piretanide excretion and sodium excretion was examined to determine tubular potency.

Main Results:

• No dose-dependent elimination of piretanide was observed within the tested dose range.
• Peak serum concentrations and urinary excretion occurred between 30 and 60 minutes.
• Elimination half-lives ranged from 60 to 90 minutes, with approximately 45% of the dose excreted unchanged in urine. Renal clearance was 90-100 ml/min, and oral clearance was 200 ml/min.
• Piretanide's half-maximal response dose was 12.1 µg/min, compared to 69.8 µg/min for furosemide and 1 µg/min for bumetanide, indicating it is 5-6 times more potent than furosemide and one-tenth as potent as bumetanide.

Conclusions:

• Piretanide demonstrates pharmacokinetic properties comparable to furosemide and bumetanide.
• Piretanide is a highly potent loop diuretic, with significantly greater potency than furosemide at the tubular level.