Alcohol and cannabis use among college students: Substitutes or complements?

AimsEconomists debate whether changes in availability of alcohol or cannabis are positively or negatively related to changes in use of the other substance. Implicit in these arguments are two competing, individual-level hypotheses—that people use alcohol and cannabis either as complements or substitutes for one another. This is the first study to test these hypotheses using micro-longitudinal data on individuals' alcohol and cannabis use on a given evening.MethodsUnited States college students who use alcohol and cannabis (n = 876) were selected from a larger sample who participated in a 30-day online daily diary study. At baseline, students reported their proclivity to use alcohol/drugs to cope with stress. Each day students reported their level of alcohol use from the prior evening as well as whether they had used cannabis.ResultsEvening levels of alcohol use and mean levels of alcohol use positively predicted the likelihood of evening cannabis use, results indicative of complementary use. This relation, however, was moderated by coping style, such that students who were more likely to use alcohol/drugs to cope were less likely to use cannabis as their evening or mean alcohol use levels increased, results indicative of substitution.ConclusionsSubstance-using college students showed evidence for complementary alcohol and cannabis use at both the within- and between-person levels. Students with a proclivity toward using alcohol/drugs to cope, however, showed evidence of substitution. These findings suggest that studies based on economic theories of substance use should take into account individual differences in substance use motives.     

Therapeutic drug monitoring of digoxin: Help or hindrance?

Summary A major role of therapeutic drug monitoring services is to advise on the dose of a drug which would be required to bring the concentration in the blood to within specific therapeutic limits. Monitoring digoxin usage constitutes a substantial part of the work load.We have examined the potential variability in recommendations for digoxin dosages based on a series of serum digoxin measurements in each of 80 out-patients.In over a third of cases a dose, which seemed to be optimal on the basis of the first assay result, would have produced concentrations outside the conventional therapeutic range when the measurement was repeated. This was despite careful supervision of medication and the timing of the blood sample in relation to its administration. In routine practice the apparent variability in dose requirements would be far greater.Objectives of therapeutic drug monitoring services remain the same, the way forward would seem to lie in their taking on a heavy commitment to counsel and supervise patients before repeated blood sampling. However, effort and resources might be better channelled into producing simple prescribing aids relating the risk of cardiotoxicity directly to the size of the maintenance dose and the individual's renal function.     

Is C2 monitoring or another limited sampling strategy superior to C0 monitoring in improving clinical outcomes in adult liver transplant recipients?

Cyclosporine (CsA) has had a major impact on the process and success of solid organ transplantation. Early in the use of CsA, therapeutic monitoring using the predose (trough, or C0) concentration became the standard of care. However, there are complications with the use of C0 monitoring that have only partly been mitigated with the advent of the micro-emulsion formulation (CsA-ME). More recently, limited sampling strategies (LSSs) for measuring the area under the CsA concentration-time curve (AUC) have been investigated to improve the monitoring of CsA post-transplantation. Many centres now routinely monitor CsA therapy using the concentration at 2 hours postdose (C2). In this paper the strength of the evidence for C2 (or other LSSs) relative to C0 monitoring of CsA-ME for improving clinically important outcomes in liver transplant patients is critically examined. Additionally, gaps in the literature are identified and recommendations are made for clinical research that could be done to provide more definitive evidence for the use of C2 or other LSSs in monitoring liver transplant patients.     

Host-targeting agents in the treatment of hepatitis C: A beginning and an end?

The development of two distinct classes of hepatitis C antiviral agents, direct-acting antivirals (DAAs) and host-targeting antivirals (HTAs), have distinctly impacted the hepatitis C virus (HCV) field by generating higher sustained virological response (SVR) rates within infected patients, via reductions in both adverse side effects and duration of treatment when compared to the old standard of care. Today DAAs are actively incorporated into the standard of care and continue to receive the most advanced clinical trial analysis. With a multitude of innovative and potent second-generation DAA compounds currently being tested in clinical trials, it is clear that the future of DAAs looks very bright. In comparison to the other class of compounds, HTAs have been slightly less impactful, despite the fact that primary treatment regimens for HCV began with the use of an HTA – interferon alpha (IFNα). The compound was advantageous in that it provided a broad-reaching antiviral response; however deleterious side effects and viral/patient resistance has since made the compound outdated. HTA research has since moved onward to target a number of cellular host factors that are required for HCV viral entry and replication such as scavenger receptor-BI (SR-BI), 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCoA reductase), cyclophilin A (CypA), fatty acid synthase (FASN) and miRNA-122. The rationale behind pursuing these HTAs is based upon the extremely low mutational rate that occurs within eukaryotic cells, thereby creating a high genetic barrier to drug resistance for anti-HCV compounds, as well as pan-genotypic coverage to all HCV genotypes and serotypes. As the end appears near for HCV, it becomes important to ask if the development of novel HTAs should also be analyzed in combination with other DAAs, in order to address potential hard-to-treat HCV patient populations. Since the treatment regimens for HCV began with the use of a global HTA, could one end the field as well?     

New therapeutic approaches to liver fibrosis: a practicable route?

The progress of research on the molecular pathogenesis of liver fibrosis and the consequent discoveries are likely to open new possibilities for therapeutic approaches to the management of this disease in the future. A key step towards this goal is a deeper comprehension of both the complex molecular and cellular mechanisms and the signaling involved in the development of hepatic fibrosis. It is not yet clear, in fact, what role apoptosis, cytokines, oxidants and other molecules play and what relationships exist between them in favouring or delaying the onset of these adverse mechanisms. At present, a unique mechanism is recognized to be the main reason for the cause and development of liver fibrosis: sustained hepatic stellate cell activation and transformation. Therefore, in this review, after considering the cause, development of fibrosis and interrelation between molecular and cellular profibrotic mechanisms, the part played in counteracting both of these actions by some anti-oxidants and anti-fibrotic molecules such as cytokines, prostacyclin and others will be taken into consideration. The gene therapy and the possible therapeutic use of liver stem cells and tissue engineering will also be dealt with briefly. At the moment, however, the efficacy of these novel strategies still needs to be further validated in animal studies and confirmed in clinical trials. Some data that are already available from in vitro and animal studies demonstrating the effectiveness of novel approaches to inhibiting or treating liver fibrosis can only offer moderate hope.     

Urine monitoring of diazepam abuse- new intake or not?

Testing for drugs-of-abuse in urine is requested for multiple reasons, including legal and workplace policies. Two cases were studied in which there was a suspicion that the patients continued to abuse diazepam, because of repeatedly positive urine samples. In these cases, diazepam metabolites were measured in urine samples by gas or liquid chromatography coupled to mass spectrometry. The concentrations of diazepam metabolites were subsequently creatinine correlated. Very long elimination times were found in the described cases. None of them had in fact ingested diazepam again during the study period. By the use of pharmacogenetic typing, one of the subjects was found to have a slow metabolism for CYP2C9 as well as for CYP2C19. In the second case, there was a possible drug interaction between diazepam and zolpidem.     

Drug interactions and protease inhibitors used in the treatment of hepatitis C: How to manage?

Purpose

The first-generation protease inhibitors (PI) boceprevir and telaprevir combined with pegylated interferon have revolutionized the treatment of type-1 hepatitis C by increasing the rates of sustained virologic response. However, they induce drug interactions, and their clinical relevance is difficult to predict. This review compiles available data on drug–drug interactions (DDI) based on their pharmacokinetic and pharmacodynamic properties with the aim of assisting clinicians in managing DDI

Methods

PubMed, drug interaction databases and hepatology and infectious disease conference abstracts were systematically searched using the key search terms “interaction”, “hepatitis C”, “telaprevir” and “boceprevir”. All known interactions were compiled and reclassified according to their pharmacokinetic and pharmacodynamic mechanisms. The state of knowledge of interaction mechanisms are reported and a therapeutic approach is proposed.

Results

Boceprevir and telaprevir are both substrates and potent inhibitors of cytochrome P450 3A4 and the drug transporter P-glycoprotein. They induce overdosage but can sometimes decrease the effect of other drugs by inducing other cytochromes. Overdosage or low dosage mainly affects drugs with a narrow therapeutic range, such as immunosuppressants or antiretrovirals. The distribution and elimination of PI are unaffected by interactions. In terms of pharmacodynamic interactions, PI can trigger drug-induced QT interval prolongation, which means that clinicians should manage such risk factors as potassium/magnesium levels or avoid other QT-prolonging drugs.

Conclusions

Management of hepatitis C therapy is complex. The key to interpreting DDI data is a solid understanding of the pharmacokinetic and pharmacodynamic profiles of the drugs involved. Their ability to inhibit cytochrome P450 3A4 and prolong the QT interval can have significant clinical consequences. This review provides a practical guide to the safe and effective management of therapy with boceprevir and telaprevir.     

Therapeutic monoclonal antibody concentration monitoring: free or total?

Most therapeutic monoclonal antibodies are designed to bind a specific antigen to elicit pharmacological effects. Accurate quantification of a therapeutic monoclonal antibody in biological matrices is essential for assessing its pharmacokinetics and selecting an effective dosing regimen. Therapeutic antibodies may exist in free, partially bound and fully bound forms in the bloodstream. The choice of which form(s) to measure and how to measure them is gaining much attention with the increase in the number of soluble therapeutic targets. This article will review the bioanalytical methods used in supporting the clinical development of the US FDA-approved therapeutic monoclonal antibodies and also discuss how different factors, such as assay format, target and antibody concentrations, and sample dilutions, can have an impact on the measurement of each form of antibody. Appreciation of which form of drug is being measured and what factors may impact measurement under different conditions are important for interpretation of the pharmacokinetics of therapeutic antibodies.     

TDM: therapeutic drug measuring or therapeutic drug monitoring?

The third round of the International Interlaboratory Quality Control Program for Therapeutic Drug Monitoring in HIV infection (QC-program) consisted of the analysis not only of plasma samples but also of patient cases. The case was composed of different topics related to the therapeutic drug monitoring of antiretroviral drugs. The participants were asked to give recommendations concerning dose adjustments, changes to the regimen, and drug-drug interactions to observe whether the expert recommendations were comparable. Of the 30 participants of the QC-program, 16 returned their comments and recommendations with regard to the patient case. The drug level was easy to judge: approximately 90% were able to correctly do so. Almost half of the recommendations (44%) given were satisfactory. Levels of knowledge regarding HIV treatment appeared to be variable among the respondents and for this reason were partly incomparable.     

Metabolic abnormalities associated with second generation antipsychotics: fact or fiction? Development of guidelines for screening and monitoring

Epidemiological studies have demonstrated a relevant increased risk of diabetes in schizophrenic patients who are treated with many atypical antipsychotics, irrespective of concomitant weight gain. Numerous case reports and some large retrospective cohort studies have documented an increased risk of diabetes with some second-generation antipsychotics (SGAs), leading different authors to identify patients on SGA as another high-risk group for diabetes in their review articles. An American consensus conference dealing with this problem has proposed much awaited guidelines for the monitoring of patients on SGA and recommended acquiring additional data, especially from large-scale prospective studies. A more recent Belgian consensus on the screening and management of antipsychotic-related metabolic disturbances has proposed a more stringent approach. Here, we will cover the current diagnosis of metabolic problems, and provide a review of antipsychotic-related metabolic problems (diabetes, lipid abnormalities and the metabolic syndrome), as well as guidelines for the screening and management of metabolic abnormalities in people treated with antipsychotic medication.     

Interferon-free hepatitis C therapy: how close are we?

Two oral direct-acting antivirals (DAA) are now available for the treatment of chronic hepatitis C infection and several generations of DAA are in development. Expectations are that, at some time in the near future, hepatitis C will be 'curable' with an all-oral DAA regimen. This article reviews the current problems associated with interferon-based hepatitis C treatments that are combined with DAAs, including adverse events and complications of therapy, contraindications, drug-drug interactions and cost. The article further discusses difficulties with new drug development and provides an opinion on the research issues still to be dealt with and the requirements for the successful implementation of such a strategy. These include lack of efficacy in certain populations, unexpected side effects, antiviral resistance, late relapse, lack of cooperation between drug developers and cost.     

Preventing hepatitis C: what do positive injectors do?

The majority of hepatitis C prevention research among injectors is concerned with preventing initial exposure to the virus. Given that the prevalence of hepatitis C among injectors is between 50 and 60 per cent, one aim should be to prevent further transmission of the virus from infected to non-infected injectors. The major aim of this study was to investigate the risk management strategies hepatitis C positive injectors might take to prevent further transmission of the virus. A total of 111 hepatitis C positive injectors were recruited and interviewed with a questionnaire designed to gather information regarding current and past injecting behaviours and risk reduction options outlined in response to a series of injecting vignettes. The responses indicated that the majority of respondents recognised the risks associated with the various injecting scenarios and could describe actions by which they could reduce those risks. However, the examination of reported options revealed that while some of these would indeed eliminate the risk of further transmission others would be less effective because they either relied on unproven methods of removing viral material from used needle and syringes or the user assumed that other injectors had knowledge equivalent to that of the respondent.     

Impact of HIV and chronic kidney disease comorbidities on hepatitis C treatment choices,drug–drug interactions and hepatitis C cure

International Journal of Clinical Pharmacy - Background Human immunodeficiency virus (HIV) co-infection and chronic kidney disease add challenges to hepatitis C virus treatment. Objective To...