ISTANBUL—Gabapentin and pregabalin relieve severe itching in most patients with chronic kidney disease (CKD), investigators reported at the 50th Congress of the European Renal Association-European Dialysis and Transplant Association.

“Our results bolster earlier data in support of a role for gabapentin and pregabalin in the treatment of a problem which is much more than intermittent irritations relieved by a satisfying scratch,” said Hugh C. Rayner, MD, consultant nephrologist at Heart of England National Health Service (NHS) Foundation Trust in Birmingham, U.K. 

His team used gabapentin and pregabalin in 71 consecutive patients with CKD stage 4 or 5, some of whom were on hemodialysis (HD) or peritoneal dialysis (PD).

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Uremic pruritus, also referred to as CKD-associated pruritus, is a common symptom in patients with end-stage renal disease, Dr. Rayner observed.  In severe cases, the symptoms may disrupt sleep and decrease quality of life, which is associated with depression and increased mortality.

Gabapentin and a related drug, pregabalin, both of which are primarily used for the treatment of epilepsy and neuropathic pain, have been shown to control itching in small randomized controlled studies involving HD patients.

Participants in the present study complained of itching that had been present for a median of six months despite the use of simple emollients or antihistamines.  
Serum calcium levels were below 2.60 mmol/L in 87% of patients and serum phosphate levels were below 1.8 mmol/L in 75% of patients.

Gabapentin was started at a dose of 100 mg once daily at night or after each dialysis session. Patients who were unable to tolerate gabapentin were offered pregabalin at a dose of 25 mg once daily at night or after each dialysis session. Patients rated median itch severity on a scale of 0 to 10, where 10 referred to the most severe itch imaginable.

Overall, gabapentin or pregabalin relieved itching in 60 patients, or 85%. Patients had a median itch severity score of 8 before treatment and 1 after treatment.

Dr. Rayner cautioned that one third of patients could not tolerate gabapentin because of adverse effects, usually over-sedation. However, many of these patients tolerated pregabalin. Because the study was not placebo-controlled, it is not possible to reliably conclude that the study drugs were always responsible for the observed effects, he said.

He was quick to emphasize, however, that the extent of improvement in itch was in line with prior placebo-controlled studies.

Dr. Rayner also noted that patients described a rapid onset of effect and a clear dose-response relationship between gabapentin/pregabalin and itch severity and were able to adjust their treatment according to their response.  

“Nephrologists need to make a stronger effort to query their CKD patients about possible skin irritation and itch,” Dr. Rayner advised. “Patients may be reluctant to acknowledge these symptoms, which they feel suggest that they have not complied with their prescribed diet or phosphate binder therapy.”

He added:  “The good news is that once the condition has been identified, patients now have an additional therapeutic option which should be recommended after simple treatments with moisturizing creams and antihistamines have failed.”

Dr. Rayner said that, to his knowledge, the study is the largest to date on the use of gabapentin and pregabalin to treat severe itching in patients with CKD stage 4 and 5, including patients on HD and PD.