Effectiveness of single dose conivaptan for correction of hyponatraemia in post-operative patients following major head and neck surgeries

Abstract

Background and Aims:Conivaptan, a vasopressin receptor antagonist, is commonly used for the treatment of euvolaemic, hypervolaemic hyponatraemia. Usually, an intravenous (IV) bolus followed by infusion is administered for many days. We decided to assess the effectiveness of single dose conivaptan for correction of hyponatraemia in post-operative patients.Methods:This was a prospective, randomised trial conducted in 40 symptomatic post-operative Intensive Care Unit (ICU) patients with a serum sodium level of ≤130 mEq/L. Group A patients received IV conivaptan 20 mg over 30 min, whereas in group B infusion of 3% hypertonic saline was started as an infusion at the rate of 20–30 ml/h. Serum sodium levels were measured at 12, 24, 48 and 72 h and the daily fluid balance was measured for 3 days. The Chi-square test, Wilcoxon signed rank test and Mann-Whitney tests were used as applicable.Results:The serum sodium levels before initiating treatment were comparable between groups. However, subsequent sodium levels at 12, 24 and 48 h showed significantly high values in group A. Though at 72 h the mean sodium value was high in group A, it was not statistically significant. Group A showed a significantly high fluid loss on day 1, 2 and 3. The mean volume of hypertonic saline required in group B showed a steady decline from day 1 to 3 and only 13 patients required hypertonic saline on the 3rd day.Conclusion:Single dose conivaptan is effective in increasing serum sodium levels in post-operative ICU patients up to 72 h associated with a significant negative fluid balance.

Efficacy of vaptans for correction of postoperative hyponatremia: A comparison between single intravenous bolus conivaptan vs oral tolvaptan

“…A single intravenous bolus of 20 or 40 mg conivaptan was found to be effective for the correction of acute hyponatremia and the effect of intermittent bolus dosing lasts up to 72 h.[ 9 10 ] Bolus dose of conivaptan 20 mg followed by an infusion of 40 mg over 24 h for the next 72 h was found to be superior than hypertonic saline in correcting hyponatremia. [ 11 ] Oral conivaptan 40 or 80 mg/day for 5 days had also shown similar effects.…”

“…Effectiveness of conivaptan for management of hyponatremia in postsurgical patients had been investigated by Rajan et al .,[ 10 ] Potts et al .,[ 21 ] Breshears et al .,[ 22 ] Buckley et al .,[ 23 ] and Marik and Rivera. [ 24 ] They have concluded that such an approach is safe and will result in a controlled and predictable increase in the serum sodium concentration.…”

Efficacy of oral tolvaptan versus 3% hypertonic saline for correction of hyponatraemia in post-operative patients

“…Vaptans such as conivaptan and tolvaptan are potent vasopressin receptor antagonists which are useful in the treatment of hypervolaemic or euvolaemic hyponatraemia associated with congestive heart failure, hepatic cirrhosis or SIADH. [ 18 19 20 21 ] Tolvaptan is a selective vasopressin V 2 receptor antagonist that blocks arginine vasopressin (AVP) binding in the distal portions of the nephron and negates AVP's antidiuretic activity leading to electrolyte-free water diuresis (aquaresis) without significant electrolyte abnormalities. The recommended starting dose of oral tolvaptan is 15 mg/day, which may be increased at daily intervals to 30 mg/day, and to a maximum of 60 mg/day.…”

“…[ 10 ] At the same time, bolus dose of conivaptan 20 mg alone as well as that followed by an infusion of 40 mg over 24 h for the next 72 h was found to be superior than HTS in this respect. [ 21 24 ]…”