Urinary acidification response to furosemide administration in patients on low-dose cyclosporine therapy.
The response of urinary acidification parameters and electrolytes to furosemide administration was prospectively studied in 9 psoriatic patients treated with a low-dose cyclosporine A schedule (initial dose: 5 mg/kg body weight) before beginning cyclosporine A, after 3 months on cyclosporine A and 1 month after cyclosporine A withdrawal. The test was also performed in 29 psoriatic patients after 3 months on 5 mg/kg body weight cyclosporine A treatment. There were no significant differences between before and after cyclosporine A treatment regarding furosemide-induced changes in urinary volume, sodium or potassium excretion. Contrarily, the post-furosemide urinary pH decrease and ammonium and titrable acid increase were significantly lower in cyclosporine-A-treated patients. Five of the 29 studied patients showed abnormal furosemide tests (17%). These patients had lower total serum CO2, urea and creatinine but similar serum potassium and fractional potassium excretion. We conclude that some patients treated with low-dose cyclosporine A therapy develop an abnormal tubular distal response to furosemide administration, suggesting an alteration in the H(+)-ATPase pump or a voltage-dependent mechanism.
Quereda
C
C
Nephrology Department, Hospital Ramon y Cajal, Madrid, Spain.
Soria
C
C
Gallego
N
N
Sabater
J
J
Pascual
J
J
Orofino
L
L
Ortuno
J
J
D000328:Adult; D016572:Cyclosporine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D005665:Furosemide; D006801:Humans; D007677:Kidney Function Tests; D007686:Kidney Tubules, Distal / Q000187:drug effects* / Q000502:physiology; D008297:Male; D011446:Prospective Studies; D006180:Proton-Translocating ATPases / Q000187:drug effects; D011565:Psoriasis / Q000188:drug therapy* / Q000453:epidemiology / Q000652:urine; D013997:Time Factors
D005665:Furosemide; D016572:Cyclosporine; D006180:Proton-Translocating ATPases