Safety and Persistence of Nalmefene Treatment for Alcohol Dependence. Results from Two Post-authorisation Safety Studies

G protein Inactivation as a Mechanism for Addiction Treatment

BACKGROUND

The endogenous dynorphin/kappa opioid receptor (KOR) system in the brain mediates the dysphoric effects of stress, and KOR antagonists may have therapeutic potential for the treatment of drug addiction, depression, and psychosis. One class of KOR antagonists, the long-acting norBNI-like antagonists, have been suggested to act by causing KOR inactivation through a cJun-kinase mechanism rather than by competitive inhibition.

METHODS

In this study, we screened for other opioid ligands that might produce norBNI-like KOR inactivation and found that nalfurafine (a G-biased KOR agonist) and nalmefene (a KOR partial agonist) also produce long-lasting KOR inactivation.

RESULTS

Neither nalfurafine nor nalmefene are completely selective KOR ligands, but KOR inactivation was observed at doses 10-100 fold lower than necessary for mu opioid receptor actions. KOR inactivation is sex-dependent, and we show that nalfurafine causes peroxide production only during estrus (low-estrogen state) or following progesterone treatment of female mice. Because KOR inactivation recovers slowly, daily treatment with submaximal drug doses causes accumulating inhibition. Daily microdosing with nalfurafine or nalmefene blocked KORs responsible for antinociceptive effects, blocked KORs mediating stress-induced aversion, mitigated KOR-mediated dysphoria during acute and protracted withdrawal in opioid-dependent mice, and blocked KOR-induced prolactin secretion. In contrast, KORs mediating the diuretic and anti-pruritic effects were not regulated by JNK.

CONCLUSIONS

Both nalfurafine and nalmefene have long histories of safety and use in humans and could potentially be repurposed for the treatment of dynorphin-mediated stress disorders.

Emerging drugs in phase II and III clinical development for the treatment of alcohol use disorder

INTRODUCTION

Alcohol Use Disorder (AUD) poses an ongoing significant global health burden. AUD is highly prevalent and affects not only the individuals with AUD, but also their communities and society at large. Even though pharmacotherapy is an integral part of AUD treatment, the few available substances show limited efficacy and limited clinical impact. Thus, there is a need for new innovative pharmacotherapeutic approaches.

AREAS COVERED

This paper provides a comprehensive review of drugs approved for the treatment of AUD as well as those currently in phase II and III development. Data from recent clinical trials has been reviewed and supplemented by additional literature based on a systematic search of the PubMed database and clinical trials registries. Compounds discussed include disulfiram, naltrexone, nalmefene, acamprosat, baclofen, sodium oxybate, doxazosin, varenicline, zonisamide, gabapentin, apremilast, ibudilast, ivermectin, tolcapone, mifepristone, suvorexant, ketamine, psilocybin, semaglutide, oxytocin and cannabidiol.

EXPERT OPINION

Even though the majority of the discussed compounds lack sufficient evidence to support their efficacy, multiple promising new treatment options are currently under investigation. Future research has to consider specific phenotypes and subgroups of AUD as well as a possible enhancement of the effects of psychotherapy through combination with pharmacotherapy. Practitioners should be encouraged to use available compounds to support existing therapeutic regimens.

Alcoholic Liver Disease in China: A Disease Influenced by Complex Social Factors That Should Not Be Neglected

Alcoholic liver disease (ALD) encompasses liver damage caused by chronic, excessive alcohol consumption. It manifests initially as marked hepatocellular steatosis and can progress to steatohepatitis, liver fibrosis, and cirrhosis. With China's rapid economic growth, coupled with a complex social background and the influence of a deleterious wine culture, the number of patients with ALD in China has increased significantly; the disease has become a social and health problem that cannot be ignored. In this review, we briefly described the social factors affecting ALD in China and elaborated on differences between alcoholic and other liver diseases in terms of complications (e.g., cirrhosis, upper gastrointestinal bleeding, hepatic encephalopathy, hepatocellular carcinoma, addiction, and other extrahepatic diseases). We also emphasized that ALD was more dangerous and difficult to treat than other liver diseases due to its complications, and that precise and effective treatment measures were lacking. In addition, we considered new ideas and treatment methods that may be generated in the future.