Lack of effect of long-term use of angiotensin-converting enzyme inhibitors by hemodialysis patients on thirst and fluid weight gain.

Volume overload is a chronic, troublesome problem in many patients on hemodialysis. These patients suffer from hyperdipsia with inability to excrete water. Angiotensin-converting enzyme inhibitor (ACEI) has been shown to decrease thirst and interdialytic weight gain in 2-4 weeks of usage. We investigated the effect of long-term use of ACEI, as levels of angiotensin II tends to go back to normal level after 6 months of use. We compared hemodialysis patients on ACEI for more than 6 months to patients not on ACEI. Seven patients were taking ACEI compared to 51 controls in the other group. Almost one third of patients in each group had an interdialytic weight gain > 5% of dry weight. No significant difference was found between the two groups with regard to interdialytic weight gain, thirst and mouth dryness scores, and interdialytic mean blood pressure change. There was no demonstrable effect of angiotensin receptor blocking drugs on weight gain or thirst. We conclude that long-term ACEI may not continue to suppress inappropriate thirst and fluid intake after 6 months in hemodialysis patients.