Effects of hydrochlorothiazide and furosemide on creatinine clearance in some hypertensive Nigerians

Hydrochlorothiazide and furosemide have been reported to alter the glomerular filtration rate (GFR) and possibly the creatinine excretion by the kidneys. Also, therapy with these diuretics, especially in the elderly, can be complicated by volume depletion resulting in prerenal azotemia. Creatinine clearance (Clcr) is considered to be the most accurate test of renal function. Unfortunately, although these diuretics are widely used in the treatment of hypertension and heart failure in the young and elderly Nigerians, their effects on renal function have been poorly investigated. We, therefore, evaluated the effects of treatment with 21-day single daily oral doses of 25 mg hydrochlorothiazide or 40 mg furosemide on Clcr in this prospective randomized study of forty Nigerians with mild to moderate uncomplicated essential hypertension (20 males and 20 females) 32 to 80 years of age and 40 age and sex-matched healthy normotensive controls while on their usual diet. Blood and 24 h urine specimens were collected at baseline and on days 7, 14 and 21. Specimens were assayed for creatinine and the corresponding Clcr for each day was calculated. Analysis of variance did not show a statistically significant effect of the diuretic regimens on Clcr over the period. This study demonstrates that single daily doses of either of these diuretics do not have a significant effect on Clcr over a short-term monotherapy.