The Effect of Ibuprofen Therapy on Water and Electrolyte Balance

Abstract

ABSTRACT. To elucidate the possibility of fluid retention during the early phase of antirheumatic therapy, 7 women (aged 37–59 years, mean 48) and 5 men (aged 41–74 years, mean 56) were studied during 2 weeks of therapy with ibuprofen, 400 mg t.i.d. They had no symptoms or signs of cardiac or renal failure and were not on diuretics or digoxin. There was a weak but significant correlation (r2 ‐0.50, p<0.01) between duration of therapy and changes in body weight indicating an average increase in body weight of 0.5% after 2 weeks' therapy. The averages of all percentual weight changes measured daily were +0.3% for the women (p<0.01) and .0.15% (NS) for the men. An initial fall in hemoglobin of 4.4% (p<0.01) during the first week was followed by an increase of 4.1% (p<0.05) during the second week. A fall in the erythrocyte volume fraction of 4% (p<0.05) occurred during the first week and was followed by an increase of 2.7% (NS) during the second week. A decreased concentration of albumin in serum was found after the first week (3.9% (p<0.05) for the women and 0.16% (NS) for the men). During the second week an average increase of 4% was seen (4.6% for the women and 3.5% for the men) (p<0.02). The average concentration of potassium in serum fell by 0.6% during the first week (NS), but during the second week an increase of 4% (p<0.02) was seen. In three women the severity of the symptoms allowed the parameters to be determined before, during and after ibuprofen therapy. The results confirmed that ibuprofen induces a moderate fluid retention in subjects with normal kidney function and without symptoms or signs of heart disease.