Hyponatremia in elderly patients treated with desmopressin for nocturia:: a review of a case series

Objective: Lately, desmopressin (dDAVP) administered orally has been demonstrated to be an effective alternative in the management of nocturia in adults. Although the safety profile of dDAVP is well known, much of the experience originates from studies in enuretic children and younger adults, and it may not be readily extrapolated to elderly patients. In order to identify factors associated with an increased risk of hyponatremia in elderly patients treated with dDAVP for nocturia, we analysed spontaneous reports accrued from clinical practice in Denmark and Sweden. Method: Following a selection procedure, the study base comprised 15 case reports. From the included reports, information was sought on concurrent diseases, concomitant medications and other factors that may predispose elderly patients to hyponatremia when treated with desmopressin. Results: The median age amongst the cases was 81 years (range 61-93 years) and 80% were females. For seven of the patients, the hyponatremia occurred during the first 3 weeks of treatment. The symptoms presented by the patients led to hospitalisation in all but one case. Among patients with information available on concomitant medication, half of them were treated with cyclooxygenase inhibitors. An excessive fluid intake could only be ascertained in one case; all 15 patients eventually recovered. Conclusion: In elderly patients treated with dDAVP for nocturia, an increased risk of hyponatremia exists in the first weeks of treatment. Compared with younger subjects, risk factors other than excessive intake of fluid appear to contribute to this adverse drug reaction.