trk-820 and Uremia

Uremic itch is a frequent and sometimes very tormenting symptom in patients with advanced or end-stage renal failure, with a strong negative impact on the quality of life. According to a representative study, the point prevalence of chronic itch is 25% in hemodialysis patients but may reach more than 50% in single cohorts depending on the country and dialysis efficacy. Not much is known regarding the pathogenesis of uremic itch. Besides parathyroid hormone, histamine, tryptase, and alteration of the calcium-phosphate metabolism have been suspected. More recently, derangements in the opioid system and an inflammatory condition have been investigated as suspected players in the pathogenesis of uremic itch, but remain unproven so far. Treatment of chronic itch in dialysis patients remains difficult. Besides topical application of rehydrating or immunomodulating compounds, such as γ-linolenic acid or tacrolimus treatment with nalfurafine may be helpful. Apart from that, gabapentin and pregabalin are promising drugs to alleviate uremic itch. In many cases, UVB phototherapy is effective in reducing the intensity of itch. When treating patients, one should take into account that most of the drugs available are not licensed for the treatment of itch. Therefore, a deliberate use of therapeutic options aiming for a good risk-benefit relation should be adopted. In very severe and refractory cases, patients suitable for renal transplantation might be switched to 'high urgency' status, as successful renal transplantation cures uremic pruritus in most of the cases.

Topics: Acupuncture Therapy; Amines; Analgesics, Opioid; Anticonvulsants; Calcineurin Inhibitors; Cyclohexanecarboxylic Acids; Gabapentin; gamma-Aminobutyric Acid; gamma-Linolenic Acid; Humans; Kidney Failure, Chronic; Morphinans; Narcotic Antagonists; Pregabalin; Pruritus; Receptors, Opioid, kappa; Receptors, Opioid, mu; Renal Dialysis; Spiro Compounds; Tacrolimus; Ultraviolet Therapy; Uremia

Uremic pruritus or chronic kidney disease-associated pruritus (CKD-aP) remains a frequent and compromising symptom in patients with advanced or end-stage renal disease, strongly reducing the patient's quality of life. More than 40% of patients undergoing hemodialysis suffer from chronic pruritus; half of them complain about generalized pruritus. The pathogenesis of CKD-aP remains obscure. Parathormone and histamine as well as calcium and magnesium salts have been suspected as pathogenetic factors. Newer hypotheses are focusing on opioid-receptor derangements and microinflammation as possible causes of CKD-aP, although until now this could not be proven. Pruritus may be extremely difficult to control, as therapeutic options are limited. The most consequential approaches to treatment are: topical treatment with or without anti-inflammatory compounds or systemic treatment with (a) gabapentin, (b) μ-opioid receptor antagonists and κ-agonists, (c) drugs with an anti-inflammatory action, (d) phototherapy, or (e) acupuncture. A stepwise approach is suggested starting with emollients and gabapentin or phototherapy as first-line treatments. In refractory cases, more experimental options as μ-opioid-receptor-antagonists (i.e., naltrexone) or κ-opioid-receptor agonist (nalfurafine) may be chosen. In desperate cases, patients suitable for transplantation might be set on 'high urgency'-status, as successful kidney transplantation will relieve patients from CKD-aP.

Topics: Acupuncture Therapy; Amines; Anti-Inflammatory Agents; Calcium Channel Blockers; Cyclohexanecarboxylic Acids; Gabapentin; gamma-Aminobutyric Acid; gamma-Linolenic Acid; Humans; Morphinans; Naltrexone; Narcotic Antagonists; Pentoxifylline; Phototherapy; Pregabalin; Pruritus; Receptors, Opioid, kappa; Renal Insufficiency, Chronic; Spiro Compounds; Tacrolimus; Thalidomide; Uremia

Topics: Administration, Oral; Animals; Capsules; Clinical Trials as Topic; Disease Models, Animal; Dose-Response Relationship, Drug; Humans; Morphinans; Pruritus; Receptors, Opioid; Renal Dialysis; Spiro Compounds; Uremia

Uremic pruritus in hemodialysis patients is intractable and no effective treatments have been established yet. Although the precise mechanism of the pruritus is still unclear, accumulating evidence suggests that activation of the micro-opioid receptors may induce pruritus in hemodialysis patients. On the other hand, activation of kappa-opioid receptors is known to control or inhibit the signals activated through micro-opioid receptors; therefore, it was expected that kappa-opioid receptor agonists would be able to reduce pruritus in patients undergoing hemodialysis. Nalfurafine hydrochloride is a novel derivative of the opioid receptor antagonist naltrexone. Nalfurafine hydrochloride is a selective kappa-opioid receptor agonist and has a potent antipruritic effect on various types of pruritus through central kappa-opioid receptor activation in non-clinical pharmacological studies. Moreover, clinical studies have demonstrated that nalfurafine hydrochloride possesses efficacy and safety in hemodialysis patients with uremic pruritus. In this review, we provide a detailed description of the activity of nalfurafine hydrochloride using published data of in vitro, in vivo nonclinical pharmacological and clinical studies in hemodialysis patients with uremic pruritus.

Topics: Animals; Humans; Morphinans; Pruritus; Receptors, Opioid, kappa; Renal Dialysis; Spiro Compounds; Uremia

Nalfurafine (nalfurafine hydrochloride, TRK-820, Remitch®) was launched as an anti-pruritic for uremic pruritus in hemodialysis patients in Japan in 2009. Since the drug is an opioid that mainly binds to κ-receptors and possesses κ-agonistic pharmacological properties and also binds partially, but very weakly, to μ-receptors, the abuse liability of the drug was assessed by using questionnaires in patients enrolled in a clinical trial evaluating the efficacy and safety of the drug. The clinical trial was conducted for up to 52 weeks in patients subjected to regular hemodialysis. End-stage renal disease (ESRD) patients with uremic pruritus (n = 146) were administered nalfurafine 5 μg intravenously after each hemodialysis session. 81 ESRD patients without uremic pruritus served as non-treatment controls. All pruritus patients answered the 3 questionnaires of "the Addiction Research Centre Inventory (ARCI)", "modified Short Opiate Withdrawal Scale (SOWS)", which provides a range of signs and symptoms of opiate withdrawal, and Severity of Dependence Scale (SDS), which measures the dependence potential of the drug. The control patients were tested with the ARCI and modified SOWS questionnaires. There were no significant differences between the nalfurafine group and control group in the ARCI and modified SOWS scales. Thus, no evidence of abuse liability was indicated in the results. Also, no significant differences in the blood pressure, respiratory rate, body temperature and pupil diameter were shown between the two groups.

Topics: Antipruritics; Female; Humans; Male; Middle Aged; Morphinans; Renal Dialysis; Spiro Compounds; Substance-Related Disorders; Surveys and Questionnaires; Time Factors; Uremia

Uremic pruritus in patients on hemodialysis is associated with depression, lower quality of life, and mortality. We studied the prevalence, awareness, and treatment of pruritus to assess how well this important condition is currently managed internationally.. Data from 35,452 patients on hemodialysis in up to 17 countries from the Dialysis Outcomes and Practice Patterns Study were analyzed to describe pruritus prevalence from 1996 to 2015. Data from 6256 patients and 268 medical directors in 17 countries in 2012-2015 were analyzed to describe predictors, effects, medical directors' awareness, and treatment of pruritus.. Patients very much or extremely bothered by itching declined from 28% in 1996 to 18% in 2015. In 2012-2015, among patients nearly always or always bothered by itching, pruritus had a major effect on work and social life; 18% used no treatment for pruritus, and 17% did not report itching to health care staff. In total, 69% of medical directors underestimated the prevalence of pruritus in their unit. Managing high serum phosphorus and low Kt/V was ranked as the most important intervention, but no relationship was found between these factors and pruritus; 57% of medical directors used oral antihistamines for first-line chronic treatment of pruritus. Gabapentin was used by 45% as first-, second-, or third-line treatment. Nalfurafine was only used in Japan.. The prevalence of pruritus in people on hemodialysis is decreasing but remains underestimated. Large numbers of patients on hemodialysis with severe pruritus do not receive treatment. There is wide variation in the use of unlicensed medications for the treatment of pruritus. These data provide a benchmark for initiatives to improve the management of uremic pruritus.. This article contains multimedia at https://vimeo.com/49458473This article contains multimedia at vimeo.com/49455976.

Topics: Aged; Aged, 80 and over; Amines; Antipruritics; Chronic Disease; Cyclohexanecarboxylic Acids; Female; Gabapentin; gamma-Aminobutyric Acid; Health Knowledge, Attitudes, Practice; Histamine Antagonists; Humans; Hyperphosphatemia; Internationality; Male; Middle Aged; Morphinans; Nephrology; Practice Patterns, Physicians'; Prevalence; Pruritus; Renal Dialysis; Risk Factors; Spiro Compounds; Surveys and Questionnaires; Uremia

Topics: Humans; Kidney Failure, Chronic; Morphinans; Pruritus; Renal Dialysis; Spiro Compounds; Uremia

Topics: Humans; Morphinans; Pruritus; Receptors, Opioid, kappa; Spiro Compounds; Uremia