Elisabeth Stribos¹, Christina Swart², Catherine de Keyser1

(1) UMC Utrecht, Department of Endocrinology, Utrecht, The Netherlands. (2) UMC Utrecht, Clinical Pharmacy, Utrecht, The Netherlands.

Since the invention of desmopressin for treatment of arginine vasopressin (AVP) deficiency in 1967, several formulations have been developed such as tablet, melting tablet, spray and intravenous infusion. We here present a case with continuous subcutaneous desmopressin infusion as a solution for a refractory arginine vasopressin (AVP) deficiency.

A 56-year old female presented with polyuria (8 L/day) since two months. Past medical history included trigeminal neuralgia for which she was operated twice as well as chronic lower back pain for which she has a neurostimulator. The AVP deficiency was confirmed with a water deprivation test. Pituitary hormone analysis showed an isolated secondary hypogonadism. The MRI scan revealed an enlarged pituitary stalk of 4 mm (which was still normal two years earlier; 1.5 mm). Since no underlying cause was found, this lead us to the final diagnosis of AVP deficiency due to an idiopathic hypophysitis.

Treatment was initiated with oral desmopressin with excellent effect on diuresis. However, in the first weeks the dosage had to be augmented continuously until maximal tolerable daily dose of 1.6 mg (severe headache with higher doses). We switched to several different formulations (desmopressin spray, desmopressin subcutaneous injections, different brand tablets) however after 1-3 weeks dosages had to be progressively increased due to polyuria. Also indapamide, carbamazepine and hydrochlorothiazide (used for the treatment of AVP deficiency before the invention of desmopressin) were tested with only minimal to no effect on diuresis. Therapy compliance was checked.

We finally decided to switch to a continuous subcutaneous desmopressin infusion as higher total daily doses could be given with less side-effects (headache). This appeared to be a very successful treatment method for the past 5 months with a dosage of 0.005 mcg/hour (very low) and resulting in a diuresis of 2.5 L/day.

In conclusion, we for the first time show the successful use of continuous subcutaneous desmopressin infusion in AVP deficiency.