Delayed opioid withdrawal-like reaction in primary biliary cirrhosis following naloxone therapy

Sodium/bile acid co-transporter inhibitors currently in preclinical or early clinical development for the treatment of primary biliary cholangitis

INTRODUCTION

Pruritus is common and often undertreated in patients with primary biliary cholangitis (PBC). Existing treatments largely have an aging and low-quality evidence base, and studies included only small numbers of patients. More recent data that has added to our understanding of pruritus treatments has often come from clinical trials where itching was a secondary outcome measure in a trial designed primarily to assess disease-modifying agents. This area represents an unmet clinical need in the management of PBC.

AREAS COVERED

In this manuscript, we first summarize the proposed mechanisms for PBC-related pruritus and the current treatment paradigm. We then present an appraisal of the existing pre-clinical and clinical evidence for the use of ileal bile acid transporter inhibitors (IBATis) for this indication in PBC patients.

EXPERT OPINION

Evidence for the efficacy of IBATis is promising but limited by the currently available volume of data. Furthermore, larger clinical trials with long-term data on efficacy, safety and tolerability are needed to confirm the role of using IBATis in clinical practice and their place on the itch treatment ladder. Additional focus should also be given to exploring the disease-modifying potential of IBATis in PBC.

Cholestasis-Associated Pruritus and Its Pruritogens

Pruritus is a debilitating symptom of various cholestatic disorders, including primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and inherited progressive familial intrahepatic cholestasis (PFIC). The molecular mechanisms leading to cholestasis-associated pruritus are still unresolved and the involved pruritogens are indecisive. As a consequence of pruritus, patients suffer from sleep deprivation, loss of daytime concentration, auto-mutilation and sometimes even suicidal ideations. Current guideline-approved therapy of cholestasis-associated pruritus includes stepwise administration of several medications, which may alleviate complaints in some, but not all affected patients. Therefore, also experimental therapeutic approaches are required to improve patients' quality of life. This article reviews the current state of research on pruritogens and their receptors, and shortly discusses the most recent experimental therapies.

The efficacy and safety of bile Acid binding agents, opioid antagonists, or rifampin in the treatment of cholestasis-associated pruritus

OBJECTIVES

The objective of this review was to evaluate the efficacy and safety of rifampin, opioid antagonists, or bile acid binding agents in the treatment of cholestasis-related pruritus (CAP) from available randomized controlled trial evidence.

METHODS

In addition to a comprehensive gray literature search, the Cochrane Library, MEDLINE, EMBASE, PubMed, and Web of Science were searched. Only full-text RCTs in participants (>75% adult) with CAP on at least one of the three medications were included. The primary outcome was change in pruritus score, recorded as a continuous or dichotomous outcome. Two independent reviewers performed trial selection and quality assessment.

RESULTS

From 487 citations, 12 RCTs were included. Rifampin (standardized mean difference [SMD]-1.62, 95% CI -3.05 to -0.18) and opioid antagonists (SMD -0.68, 95% CI -1.19 to -0.17) significantly reduced CAP. The two cholestyramine studies were too heterogeneous to pool. Although cholestyramine (P= 0.35) and rifampin (P= 0.96) were not associated with greater side effects compared with placebo, opioid antagonists were (number needed to harm = 2.6, 95% CI 1.4-25).

CONCLUSIONS

The available RCTs are small, few in number, and use varying scales for measuring pruritus. Although both opioid antagonists and rifampin demonstrated a reduction in pruritus, there were insufficient data to judge the efficacy of cholestyramine. Opioid antagonists were associated with transient side effects in a significant proportion of patients. A longer well-designed randomized controlled trial is needed to confirm the efficacy of bile acid binding agents and accurately assess adverse events.

Extrahepatic manifestations of cholestatic liver diseases: pathogenesis and therapy

Pruritus, fatigue, and metabolic bone disease are frequent complications of cholestatic liver diseases, which can be quite distressing for the patient and can considerably reduce the quality of life. The molecular pathogenesis of these extrahepatic manifestations of cholestasis is poorly understood, and hypotheses to explain these symptoms are being discussed. This article provides treatment recommendations for the complications of cholestasis based on putative pathomechanisms and summarizes recent experimental and clinical data involving management options.

Extrahepatic manifestations of cholestatic liver diseases: pathogenesis and therapy

Pruritus, fatigue, and metabolic bone disease are frequent complications of cholestatic liver diseases, which can be quite distressing for the patient and can considerably reduce the quality of life. The molecular pathogenesis of these extrahepatic manifestations of cholestasis is poorly understood, and hypotheses to explain these symptoms are being discussed. This article provides treatment recommendations for the complications of cholestasis based on putative pathomechanisms and summarizes recent experimental and clinical data involving management options.

Effect of oral naltrexone on pruritus in cholestatic patients

AIM

To determine the efficacy and potential complications of oral naltrexone used in the treatment of pruritus in cholestatic patients and to compare them with other studies.

METHODS

Thirty-four enrolled cholestatic patients complaining of pruritus were studied. In the initial phase, pruritus scores during day and night were evaluated. Subsequently, patients were given a placebo for one week followed by naltrexone for one week. In each therapeutic course (placebo or naltrexone) day and night pruritus scores were distinguished by a visual analogue scale (VAS) system and recorded in patients' questionnaires.

RESULTS

Both naltrexone and placebo decreased VAS scores significantly. Naltrexone was more effective than placebo in decreasing VAS scores. Both day and night scores of pruritus decreased by half of the value prior to therapy in thirteen patients (38%). Daytime pruritus improved completely in two patients (5.9%), but no improvement in the nighttime values was observed in any patient. Sixteen patients (47%) suffered from naltrexone complications, eleven (32%) of them were related to its withdrawal. Complications were often mild. In the case of withdrawal, the complication was transient (within the first 24-28 h of therapy) and self-limited. We had to cease the drug in two cases (5.9%) because of severe withdrawal symptoms.

CONCLUSION

Naltrexone can be used in the treatment of pruritus in cholestatic patients and is a safe drug showing few, mild and self-limited complications.

Pruritus and fatigue in primary biliary cirrhosis

Pruritus and fatigue are the most common symptoms of patients with PBC, and both have marked negative impact on quality of life. Over the past decade, evidence has emerged supporting a role of the central nervous system in the pathogenesis of these two common manifestations of PBC. There is no evidence that the pruritus of cholestasis is mediated in the skin. Clinical and laboratory data do support a role of the opioid neurotransmitter system in the mediation of the pruritus of cholestasis; a central mechanism has been proposed. Treatment with opiate antagonist is thus a specific alternative. Studies of the behavioral consequence of the pruritus of cholestasis, scratching activity, allow for the design of clinical trials with objective end-points. The etiology of fatigue is unknown. A central component is being considered. The identification of objective alterations in fatigue and the adoption of a definition that incorporates the perception and the behavioral consequences of fatigue should facilitate the development of objective methodology. The potential role of various neurotransmitter systems, including the serotonin system and the opioid system, in the mediation of the fatigue of PBC seems to merit further investigation.

Pain as a complication of use of opiate antagonists for symptom control in cholestasis

Controlled trials have suggested that opiate antagonist therapy may be effective for the treatment of the symptoms of cholestasis. The oral opiate antagonist naltrexone in particular has started to enter into routine clinical use for amelioration of cholestatic itch. Attention regarding the side effects of opiate antagonist therapy has, to date, largely focused on an opiate withdrawal-type reaction (which can be controlled effectively by titrated therapy introduction regimens). Here we describe 3 cases of a further clinically important side effect, loss of control of pain resulting from other pathologies, which in each case necessitated the withdrawal of hitherto clinically effective opiate antagonist therapy. Of the 14 patients treated by our unit with opiate antagonist agents for the control of cholestatic symptoms, 13 (93%) showed resolution of, or significant improvement in, symptoms. Of the 13 patients showing a clinical response, 7 (54%) subsequently had to discontinue therapy because of side effects (including the 3 patients with uncontrolled pain). It is our experience that in the routine clinical setting, opiate antagonists are highly effective for the treatment of cholestatic symptoms. In practice, however, their usefulness is limited by their side-effect profile.

Efficacy and safety of oral naltrexone treatment for pruritus of cholestasis, a crossover, double blind, placebo-controlled study

BACKGROUND/AIMS

To assess the efficacy and safety of naltrexone for the short and long term treatment of pruritus of cholestasis.

METHODS

Twenty patients with pruritus and cholestasis were included. A baseline pruritus score was obtained over 1 week. Patients were then randomized to receive 50 mg/day of naltrexone or placebo for 2 weeks. Subsequently, a 1-week washout period ensued and patients were crossed over to the other therapy for 2 additional weeks. Pruritus was assessed daily with a visual analogue scale (VAS) from 0 to 10. Patients whose pruritus decreased >50% of basal with naltrexone received naltrexone 50 mg/day for 2 additional months.

RESULTS

Mean basal VAS was similar in both groups. VAS showed greater and more significant changes with naltrexone than with placebo (P<0.0003). In nine out of 20 patients (45%) receiving naltrexone, pruritus decreased >50% compared to basal value, including five whose pruritus disappeared completely. No significant changes were observed in serum biochemistry. Most of the adverse events that occurred during the first 48 h of naltrexone therapy were consistent with opioid withdrawal-like phenomena and spontaneously disappeared 2 days after starting treatment.

CONCLUSIONS

Naltrexone can be considered as an alternative option to treat pruritus of cholestasis. In the current study, side effects were transient and did not require specific medication.

Cholestatic syndromes

Further insights into the molecular regulation of bile acid transport and metabolism have provided the basis for a better understanding of the pathogenesis of cholestatic liver diseases. Novel insights into the mechanisms of action of ursodeoxycholic acid should advance our understanding of the treatment of cholestatic liver diseases. Mutations of transporter genes can cause hereditary cholestatic syndromes in both infants and adults as well as cholesterol gallstone disease. Important studies have been published on the pathogenesis, clinical features, and treatment of primary biliary cirrhosis, drug-induced cholestasis, and cholestasis of pregnancy.