Effects of Specific Inhibition of Cyclooxygenase-2 on Sodium Balance, Hemodynamics, and Vasoactive Eicosanoids

• Published in: The Journal of pharmacology and experimental therapeutics Vol. 289; no. 2; p. 735
• Main Authors: Catella-Lawson, F, McAdam, B, Morrison, B W, Kapoor, S, Kujubu, D, Antes, L, Lasseter, K C, Quan, H, Gertz, B J, FitzGerald, G A
• Format: Journal Article
• Language: English
• Published: United States American Society for Pharmacology and Experimental Therapeutics 01.05.1999
• Subjects: 6-Ketoprostaglandin F1 alpha - analogs & derivatives; 6-Ketoprostaglandin F1 alpha - blood; Aged; Aged, 80 and over; Blood Platelets - drug effects; Blood Platelets - metabolism; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors - toxicity; Double-Blind Method; Eicosanoids - metabolism; Female; Glomerular Filtration Rate - drug effects; Hemodynamics - drug effects; Humans; Indomethacin - toxicity; Isoenzymes - metabolism; Lactones; Male; Membrane Proteins; Middle Aged; Prostaglandin-Endoperoxide Synthases - metabolism; Sodium - metabolism; Sodium - urine; Sulfones; Thromboxane B2 - analogs & derivatives; Thromboxane B2 - blood; Thromboxane B2 - urine; Water-Electrolyte Balance - drug effects
• ISSN: 0022-3565; 1521-0103

Conventional nonsteroidal anti-inflammatory drugs inhibit both cyclooxygenase (Cox) isoforms (Cox-1 and Cox-2) and may be associated with nephrotoxicity. The present study was undertaken to assess the renal effects of the specific Cox-2 inhibitor, MK-966. Healthy older adults ( n = 36) were admitted to a clinical research unit, placed on a fixed sodium intake, and randomized under double-blind conditions to receive the specific Cox-2 inhibitor, MK-966 (50 mg every day), a nonspecific Cox-1/Cox-2 inhibitor, indomethacin (50 mg t.i.d.), or placebo for 2 weeks. All treatments were well tolerated. Both active regimens were associated with a transient but significant decline in urinary sodium excretion during the first 72 h of treatment. Blood pressure and body weight did not change significantly in any group. The glomerular filtration rate (GFR) was decreased by indomethacin but was not changed significantly by MK-966 treatment. Thromboxane biosynthesis by platelets was inhibited by indomethacin only. The urinary excretion of the prostacyclin metabolite 2,3-dinor-6-keto prostaglandin F 1α was decreased by both MK-966 and indomethacin and was unchanged by placebo. Cox-2 may play a role in the systemic biosynthesis of prostacyclin in healthy humans. Selective inhibition of Cox-2 by MK-966 caused a clinically insignificant and transient retention of sodium, but no depression of GFR. Inhibition of both Cox isoforms by indomethacin caused transient sodium retention and a decline in GFR. Our data suggest that acute sodium retention by nonsteroidal anti-inflammatory drugs in healthy elderly subjects is mediated by the inhibition of Cox-2, whereas depression of GFR is due to inhibition of Cox-1.