Disulfiram implantation: placebo, psychological deterrent, and pharmacological deterrent effects

Medications for the Treatment of Alcohol Dependence-Current State of Knowledge and Future Perspectives from a Public Health Perspective

No single effective therapy for alcohol abuse has been found, despite it being a serious sociological and economic problem for hundreds of years. It seems difficult to find a single drug as a panacea for the alcohol problem due to the complexity of the pathophysiology of alcohol dependence. The purpose of this narrative review is to review existing and potentially future pharmaceuticals for the treatment of alcohol dependence in the most affordable way possible. Psychotherapy is the mainstay of treatment for alcoholism, while few drugs approved by legislators are available in the augmentation of this treatment, such as acamprosate, disulfiram, and naltrexone, approved by the FDA, and nalmefene by the EMA. There are recent reports in the literature on the possibility of using baclofen, topiramate, varenicline, and gabapentin in the treatment of alcohol dependence. Moreover, the results of recent clinical trials using psychoactive substances such as psilocybin and MDMA appear to be a breakthrough in the modern treatment of alcohol abuse. Despite this initial optimism, a lot of scientific effort is still needed before new pharmacological methods supporting the treatment of alcohol dependence syndrome will be widely available.

Use of fomepizole (4-methylpyrazole) for acetaminophen poisoning: A scoping review

INTRODUCTION

Acetaminophen (paracetamol, APAP) poisoning is a prominent global cause of drug-induced liver injury. While N-acetylcysteine (NAC) is an effective antidote, it has therapeutic limitations in massive overdose or delayed presentation. The objective is to comprehensively review the literature on fomepizole as a potential adjunct antidote for acetaminophen toxicity.

METHODS

A scoping review was performed using standardized search terms from inception through July 2021.

RESULTS

Reports on fomepizole as a therapeutic adjunct for APAP toxicity span heterogeneous types of evidence. Eleven preclinical studies (in vitro and animal), fourteen case reports/series, and one human volunteer study were included. Fomepizole's action is mediated by inhibition of CYP2E1 to prevent oxidant stress generation, and inhibition of c-Jun N-terminal kinase (JNK) to decrease amplification of oxidant stress signaling to mitochondria. Studies have shown a reduction in oxidative metabolites likely by shunting metabolism away from CYP2E1 and a resultant decrease in liver injury in animals, independent of CYP2E1 interactions. Fomepizole has been linked to few adverse effects.

CONCLUSION

Based on in vitro and animal studies, and bolstered by case reports, fomepizole likely offers benefit as an adjunct antidote for APAP toxicity, however this remains to be shown in a human trial. NAC remains the standard of care antidote, but given that fomepizole is approved and generally safe, it may be considered for APAP toxicity as off-label use by experienced clinicians, in rare circumstances associated with increased risk of hepatotoxicity despite standard NAC dosing. The marginal clinical benefit of fomepizole adjunct therapy beyond NAC monotherapy remains to be clearly defined, and routine use for APAP overdose is premature based on current evidence.

Disulfiram Implantation for the Treatment of Alcoholism: Clinical Experiences from the Plastic Surgeon's Point of View

Background

Disulfiram implantation is a widely used treatment alternative for alcohol abuse, yet reports on the surgical aspect of disulfiram implantation with respect to patient and drug-related treatment efficacy and wound complications are very limited. We present our clinical experiences with disulfiram implantation and discuss the surgical outcomes obtained with different anatomical planes for implantation.

Methods

Medical records of all patients referred to our clinic from the psychiatry department between 2007 and 2013 for disulfiram implantation were retrospectively analyzed. Implantation was carried out using 10 sterile Disulfiram tablets (WZF Polfa S.A.), each tablet containing 100 mg of disulfiram. The procedure was carried out by implanting the tablets randomly in either a subcutaneous or an intramuscular plane. The location and the plane of implantation and the complications were recorded for each patient and compared to determine the differences in the outcomes.

Results

A total of 32 implantation procedures were evaluated for this study. Twenty-five implants were placed in the intramuscular plane (78.2%), while seven implants were placed subcutaneously (21.8%). Exposure was encountered in three of the seven subcutaneous implants (42.9%), while no exposure was seen with the intramuscular implants. Incomplete absorption of the tablets was encountered in one patient with a previous subcutaneous implant who presented 1 year later for re-implantation as part of the continuation of therapy.

Conclusions

To overcome the issue of treatment continuation in the case of disulfiram therapy, which may be ceased due to frequently encountered wound complications, we believe that implantation in the subscapular intramuscular plane allows both uneventful healing and an out-of-reach implant location.

Long-acting Preparations in Substance Abuse Management: A Review and Update

Many pharmacological approaches have been used in managing substance use disorders. Conventional pharmacological agents have relatively short durations of action which make them vulnerable to non-adherence and relapse to substance use disorder. To overcome this problem, long-acting preparations have been developed with the aim of reducing the frequency of use and hence improving adherence. This review takes a broad overview of the long-acting preparations available for the management of substance use disorders. The pharmacology, advantages and disadvantages of these preparations are discussed. Many of these preparations hold promise for improving patient outcomes.

The status of disulfiram: a half of a century later

For more than 55 years, disulfiram has been approved by the Food and Drug Administration for the treatment of alcohol dependence. It is a unique medication that relies on "psychological threat" to avoid disulfiram-ethanol reactions. This paper reviews the history of disulfiram treatment, the current status of disulfiram treatment, the ensuing developments in disulfiram use in treating various addictions, and future directions. Clinical trials using disulfiram for the treatment of alcohol, cocaine, or co-occurring alcohol + cocaine dependence were included in this review. Disulfiram efficacy studies focusing on supervised, implant, and combination pharmacotherapies were also examined. In clinical trials, disulfiram has demonstrated inconsistent results in helping patients to abstain from alcohol, and patients poorly adhere to a disulfiram-treatment regimen. This has raised questions about disulfiram's practicality in the treatment of alcohol dependence. Recently, however, disulfiram has gained attention as a complementary agent to newer pharmacological medications, such as an opiate antagonist that specifically reduces alcohol craving. One hypothesis is that disulfiram would assist patients in gaining psychological control over drinking when given in conjunction with an opiate antagonist that would act directly on reducing alcohol craving. Preliminary evidence also suggests that disulfiram treatment could be a viable treatment for cocaine dependence because it was shown to reduce cocaine use among nonalcoholic, cocaine-dependent patients.

Implantable technology for long-term delivery of nalmefene for treatment of alcoholism

Pharmacotherapy treatment for alcoholism is limited by poor compliance, adverse effects, and fluctuating drug levels after bolus administration. A long-term delivery system would improve upon these limitations. The current study describes the characterization of a sustained release implant containing nalmefene, an opioid antagonist, for treatment of alcoholism. Nalmefene was blended with ethylene vinyl acetate (EVA), extruded into 2.8 mm x 27 mm rods, and coated with EVA to optimize release. In vitro release was determined by HPLC, and in vivo release characteristics after subcutaneous implantation into rats were determined by LC-MS/MS analyses. Extrusion produced rods containing 80.09 +/- 6.0 mg nalmefene. In vitro release was high from the uncoated rods, and they were depleted of drug fairly quickly; however EVA coatings maintained release over longer periods. The 25 wt.% coated rods provided in vitro release of 0.36 mg/day/rod, and in vivo release of 0.29 mg/day/rod over 6 months, and showed dose-dependent nalmefene plasma concentrations (one rod: 3.33 +/- 0.56 ng/ml, three rods: 10.19 +/- 2.31 ng/ml). After explantation, nalmefene plasma concentrations were undetectable by 6 h. A sustained release nalmefene rod provides 6 months of drug with no adverse effects.

Depot preparations of disulfiram: experimental and clinical results

Patient compliance with disulfiram is a troublesome clinical problem. Several strategies have been proposed as a solution to the problem, including subcutaneous implantation of disulfiram. However, well controlled studies of alcoholics and healthy volunteers have failed to discover a pharmacological effect of implanted disulfiram. A major reason for this failure appears to be poor absorption from an inadequate dose. Assessment of new sustained release formulation of depot disulfiram has been found to provoke a mild disulfiram-ethanol reaction (DER). Only a more severe DER would be expected to deter further drinking. If problems with absorption and appropriate dosing of disulfiram can be resolved or a depot preparation of the active metabolite of disulfiram can be prepared, implants might find continued clinical use.

Disulfiram implant: a double-blind placebo controlled follow-up on treatment outcome

Seventy-six alcohol-dependent patients participated in a study of the clinical effect of implanted disulfiram (DS). The patients were randomized to a DS group (n = 40), receiving a subcutaneous abdominal implantation of 10 x 100 mg DS tablets and a placebo group (PL group) receiving an implantation of 9 x 100 mg calcium phosphate tablets together with one calcium phosphate tablet containing 1 mg DS. Both groups believed they were receiving DS. At admission there was no significant difference between the DS and PL groups with regard to demographic characteristics, psychosocial adjustment, drinking variables, medical disorders, or laboratory results. After a study period of approximately 300 days, 63 patients (33 DS; 30 PL) were assessed using a battery of tests. There was no significant difference between the groups with regard to reduction in average alcohol consumption, number of days to the first alcohol intake after implantation, or level of psychosocial function. Nevertheless, both groups reduced their ethanol consumption significantly, probably due to the psychological deterrent effect. The DS implant did result in a significantly higher incidence of wound complications. This study does not support the idea that a 1-g DS implant has any significant clinical effect different from the implant containing only 1 mg DS (placebo).

Biological markers and therapeutic outcome in alcoholic disease: a twelve-year survey

The early diagnosis and evaluation of the biological consequences of alcohol abuse are reviewed in a population of 401 chronic alcoholics admitted to our Toxicological Unit from January 1973 to the end of December 1984; selected cases were treated with disulfiram implantation. The results of the study indicate that anemia with increased globular volume of erythrocytes, elevated serum gamma-glutamyl-transferase activity, increased postprandial cholalemia, and increased elimination of pentane in the breath can be considered suitable markers for the early diagnosis of alcohol abuse. Disulfiram implantation significantly prolonged the abstinence duration in the treated patients.

Implantation of disulfiram in rats

The biochemical and pharmacological effects of disulfiram implantation were studied in rats. Sterile disulfiram pellets (1000 mg/kg) were implanted subcutaneously. Groups of 5 rats were killed after 3, 7, 14, 28 and 56 days. The release of disulfiram during the first week corresponded to a daily dose of 12--16 mg/kg and during the following period to 5--8 mg/kg. The activity of the low-Km aldehyde dehydrogenase in liver and brain, the carboxylesterase activity in liver and the dopamine-beta-hydroxylase activity in heart were significantly decreased by approximately 45, 35, 20 and 35% respectively at all periods tested. The rate of ethanol elimination, the activity of monoamine oxidase in the brain, and the content of cytochrome P-450 in the liver were unaffected. The level of norepinephrine in the brain was slightly decreased after 14 days. The acetaldehyde level in blood after ethanol injection (1.0 g/kg) was 55--60 microM in the disulfiram group and 25--30 microM in the control group. Ethanol administration caused a slightly decreased blood pressure and increased respiratory rate 14 days after implantation but not after 28 days.

Patient management in disulfiram implant therapy

Data from 100 disulfiram implant, placebo, and no-implant control patients demonstrate the effectiveness of the disulfiram implant in keeping the alcoholic dry. However, the superiority of the disulfiram implant group over the placebo group is interpreted as evidence of a pharmacological component to the procedure operating independent of the disulfiram-ethanol reaction (DER). Hypotheses involving inhibition of aldehyde dehydrogenase or inhibition of dopamine-beta-hydroxylase are offered as mechanisms by which the pharmacological effect may be mediated. Finally, in view of the low (approximately 0.5) probability with which a DER follows ingestion of alcohol by a disulfiram implant patient, it is suggested that the approach to patient management should be changed to maximize the effectiveness of the disulfiram implant procedure. Guidelines are given.