Endocrine Abstracts

Introduction: Terlipressin is a non-selective vasopressin analogue used in patients with decompensated cirrhosis, gastrointestinal haemorrhage or hepatorenal syndrome. It directly binds to V1 receptors improving circulatory volume by causing splanchnic vasoconstriction and portal hypertension inhibition, and has a full V2 receptor agonism in the collecting duct. In consequence, it increases reabsorption of water and can lead to a decrease in plasma osmolality and hyponatremia. Hyponatremia induced by Terlipressin is uncommon (1/1.000 to <1/100, Summary of Product Characteristics). Maximal plasma levels are reached after 1-2h following iv administration and metabolic elimination takes place within a 4-6 h period.

Case Presentation: We present the case of a 46-year-old man admitted to hospital with cirrhosis needing liver resection for liver metastases from colorectal cancer. Patient was treated with 1 mg of terlipressin intravenously every 6 h and isotonic intravenous maintenance fluids (0.9% NaCl) 1000 ml every 24 h. 36 h later he presented with lethargy, confusion, nausea and vomiting. Laboratory findings showed severe hyponatremia (108 mmol/l [134-145]) with low osmolality (231 mOsm/kg [280-305], and normal blood glucose levels (100 mg/dl). He was euvolemic at physical examination. Natremia levels 36 h before the start of terlipressin treatment were 132 mmol/l. Urinary osmolarity and urinary sodium were not available at this moment, given the priority of correcting the symptomatic severe hyponatremia. Treatment with intravenous infusion of hypertonic saline was started and terlipressin was discontinued, sodium levels returning to normal over 48 h (132 mmol/l [134-145]).

Conclusion: Hyponatremia induced by Terlipressin is uncommon and can develop rapidly. It is reversible with cessation of therapy and requires careful consideration. This case is an illustration of this undesirable effect. As endocrinologists, we must be familiar with terlipressin pharmacokinetic properties. Sodium levels and fluid balance should be monitored intensively and immediately after first terlipressin dose.