Successful difelikefalin use in severe chronic kidney disease-associated pruritus in a patient with tertiary hyperparathyroidism: a case report

Background Chronic kidney disease-associated pruritus (CKD-aP) is a frequently experienced, unpleasant skin condition. Difelikefalin is indicated for the treatment of moderate-to-severe CKD-aP in adult patients on hemodialysis. Reports of difelikefalin effectiveness in complex patient cases encountered in routine clinical practice are rare. Case presentation The presented patient had a complex interplay of morbidities, most notably diabetes mellitus type 2, tertiary hyperparathyroidism, end-stage renal disease (ESRD), and CKD-associated mineral bone disease (CKD-MBD), all of which are associated with the development and severity of CKD-aP. The patient’s CKD-aP proved resistant to H ₁ -receptor antagonists and gabapentin and showed no improvement after parathyroidectomy. Treatment with difelikefalin rapidly and sustainedly improved symptoms, with a brief recurrence of itch towards the end of each long interdialytic interval. Apart from a short episode of vertigo at initiation of treatment, no adverse events were observed over the long duration of treatment (more than two years). Conclusions Difelikefalin, an agonist of the kappa opioid receptor, acts independently of the itch-causing mechanisms associated with the comorbidities present in the patient, notably diabetes mellitus type 2, tertiary hyperparathyroidism, ESRD, and CKD-MBD. This may explain the sustained effectiveness of difelikefalin throughout the patient’s complex clinical history.