The individual variation in pharmacokinetics and pharmacodynamics of furosemide in young normal male subjects

Abstract. Following a 24 h control period in the ward 80 mg furosemide was injected intravenously to ten young healthy, male volunteers. The serum clearance of furosemide (Cl_s) was between 140 and 201 ml min^-1 and on the average the renal clearance was 66% of Cl_s. During the initial 30 min period a maximum additional excretion rate of sodium of 3·3 mmol min^-1 was reached at an excretion rate of 0·8 mg furosemide min^-1. A marked initial drop in creatinine clearance (Cl_cr) was noted and Cl_{cr(24 h)} showed an average decrease of 12% after the drug administration. The serum concentration of potassium was decreased at 1 and 2 h after the injection and of sodium from 2 h and on. The concentration of albumin in serum increased by 3% ( P < 0·05) already after 5 min. After 2 h a maximum increase of 14% was reached. After 8 min diastolic blood pressure was increased by 13% ( P < 0·05), whereas systolic blood pressure reached a significant decrease gradually (7% after 3 h).