Nefazodone-induced liver failure: report of three cases

Metabolic bioactivation of antidepressants: advance and underlying hepatotoxicity

Many drugs that serve as first-line medications for the treatment of depression are associated with severe side effects, including liver injury. Of the 34 antidepressants discussed in this review, four have been withdrawn from the market due to severe hepatotoxicity, and others carry boxed warnings for idiosyncratic liver toxicity. The clinical and economic implications of antidepressant-induced liver injury are substantial, but the underlying mechanisms remain elusive. Drug-induced liver injury may involve the host immune system, the parent drug, or its metabolites, and reactive drug metabolites are one of the most commonly referenced risk factors. Although the precise mechanism by which toxicity is induced may be difficult to determine, identifying reactive metabolites that cause toxicity can offer valuable insights for decreasing the bioactivation potential of candidates during the drug discovery process. A comprehensive understanding of drug metabolic pathways can mitigate adverse drug-drug interactions that may be caused by elevated formation of reactive metabolites. This review provides a comprehensive overview of the current state of knowledge on antidepressant bioactivation, the metabolizing enzymes responsible for the formation of reactive metabolites, and their potential implication in hepatotoxicity. This information can be a valuable resource for medicinal chemists, toxicologists, and clinicians engaged in the fields of antidepressant development, toxicity, and depression treatment.

Cell-based assay using glutathione-depleted HepaRG and HepG2 human liver cells for predicting drug-induced liver injury

Immortalized liver cells have been used for evaluating the toxicity of compounds; however, excessive glutathione is considered to lessen cytotoxicity. In this study, we compared the effects of glutathione depletion on cytotoxicities of drugs using HepaRG and HepG2 cells, which express and lack drug-metabolizing enzymes, respectively, for predicting drug-induced liver injury (DILI) risks. These cells were pre-incubated with L-buthionine-S,R-sulfoximine (BSO) and then exposed to 34 test compounds with various DILI risks for 24 h. ATP level exhibited the highest predictability of DILI among tested parameters. BSO treatment rendered cells susceptible to drug-induced cytotoxicity when evaluated by cell viability and caspase 3/7 activity with the sensitivity of cell viability from 50% in non-treated HepaRG cells to 71% in BSO-treated HepaRG cells. These results indicate that cytotoxicity assays using GSH-depleted HepaRG cells improve the predictability of DILI risks. However, HepaRG cells were not always superior to HepG2 cells when assessed by ATP level. The combination of HepG2 and HepaRG cells index produced the best prediction in the cases of caspase 3/7 acitivity and ATP level. In conclusions, the developed highly sensitive cell-based assay using GSH-reduced cells would be useful for predicting potential DILI risks at an early stage of drug development.

Antidepressant-lnduced Liver Injury

Objective:

To review principles of drug-induced liver injury (DILI), summarize characteristics of antidepressant-mediated liver Injury, and provide recommendations for monitoring and management.

Data Sources:

A search relating to antidepressant-induced liver injury was performed using MEDLINE (1966–March 2007). Search terms included antidepressant, cholestasis, hepatotoxicity, jaundice, liver injury, toxic hepatitis, and transaminases. Reference citations not Identified in the initial database search were also utilized.

Study Selection and Data Extraction:

All English-language case reports, letters, and review articles identified from the data sources were used. Case reports and letters relating to hepatotoxicity from antidepressant overdose were excluded.

Data Synthesis:

Antidepressant-induced liver injury described in published cases were of the idiopathic type and, by definition, cannot be predicted based on dose or specific risk factors. Paroxetine had the largest number of cases within the selective serotonin-reuptake inhibitor class. Nefazodone, a serotonin–norepinephrine reuptake inhibitor, appeared to have the most serious cases and is the only antidepressant agent that carries a Food and Drug Administration Black Box Warning regarding hepatotoxiciiy. The tricyclic antidepressants and monoamine oxidase Inhibitors are capable of producing hepatotoxicity, but fewer cases with these agents have been reported in the past 15 years, possibly due to a decline in their use. Causality has not been well established in all reports due to the concurrent use of other drugs and/or underlying liver disease.

Conclusions:

Most antidepressant agents have the potential to produce idiopathic liver injury. There is no way to prevent idiopathic DILI, but the severity of the reaction may be minimized with prompt recognition and early withdrawal of the agent. The clinician must be careful to provide ongoing therapy of the underlying depressive disorder and be aware of possible drug discontinuation syndromes should potential hepatotoxicity be suspected.

Use of Antidepressant Drugs in Transplant Recipients

Depression is the most prevalent psychiatric disorder in transplant recipients and may lead to noncompliance and negative outcomes without psychosocial and pharmacologic interventions. The pharmacologic treatment of depression in this patient population is complicated by complex immunosuppressant drug regimens and multiple potential drug interactions that can adversely affect the newly transplanted organs. This review provides a brief overview of the currently available antidepressant medications and highlights the clinically important features each class of agents in transplant recipients. Newer agents selective serotonin reuptake inhibitors, venlafaxine, bupropion, nefazodone, and mirtazapine are discussed as well as tricyclic antidepressants and monoamine oxidase inhibitors. A brief discussion of St. John's wort and its impact on posttransplant drug therapy is also included.

Involvement of mitochondrial dysfunction in nefazodone-induced hepatotoxicity

Nefazodone (NEF) is an antidepressive agent that was widely used in the treatment of depression until its withdrawal from the market, due to reports of liver injury and failure. NEF hepatotoxicity has been associated with mitochondrial impairment due to interference with the OXPHOS enzymatic activities, increased ROS generation and decreased antioxidant defenses. However, the mechanisms by which NEF induces mitochondrial dysfunction in hepatocytes are not completely understood. Here, we investigated the mitochondrial mechanisms affected upon NEF exposure and whether these might be linked to drug hepatotoxicity, in order to infer liabilities of future drug candidates. Two moderately hepatotoxic NEF concentrations (20 and 50 μM) were selected from dose-response growth curves performed in HepG2 cells. Cell viability, caspase activity, nuclear morphology, mitochondrial transmembrane potential, mitochondrial superoxide levels, and the expression of genes associated with different cellular pathways were evaluated at different time points. NEF treatment led to an increase in the expression of genes associated with DNA-damage response, antioxidant defense and apoptosis and a decreased expression of genes encoding proteins involved in oxidative phosphorylation, DNA repair, cell proliferation and cell cycle progression, which seem to constitute mechanisms underlying the observed mitochondrial and cell function impairment.

Pharmacological treatment of anxiety disorders: current treatments and future directions

Modern pharmacological treatments for anxiety disorders are safer and more tolerable than they were 30 years ago. Unfortunately, treatment efficacy and duration have not improved in most cases despite a greater understanding of the pathophysiology of anxiety. Moreover, innovative treatments have not reached the market despite billions of research dollars invested in drug development. In reviewing the literature on current treatments, we argue that evidence-based practice would benefit from better research on the causes of incomplete treatment response as well as the comparative efficacy of drug combinations and sequencing. We also survey two broad approaches to the development of innovative anxiety treatments:the continued development of drugs based on specific neuroreceptors and the pharmacological manipulation of fear-related memory. We highlight directions for future research, as neither of these approaches is ready for routine clinical use.

Which psychotropic medications induce hepatotoxicity?

OBJECTIVE

Safe prescribing practices to minimize pharmaceutically induced liver damage or worsening of preexisting conditions require knowledge about medicines with hepatotoxic potential. This paper reviews psychotropic medications and their effects on the liver.

METHODS

A MEDLINE search was performed utilizing the phrase "drug-induced liver injury" with various categories of psychiatric drugs. Only articles written in English were utilized.

RESULTS

Hepatotoxicity can be acute or chronic in nature. Medication discontinuation is necessary in acute forms, while close monitoring is required in milder forms of medication-induced chronic liver damage. Nefazodone, pemoline and/or tacrine are the highest offenders. Carbamazepine and valproate products (e.g., divalproex) can lead to this adverse event and should be avoided in patients with liver disease, persons with alcohol misuse or those consuming high doses of acetaminophen.

CONCLUSION

Knowing the risk levels associated with various medicines is important; prescribing multiple drugs with hepatotoxic effects should be avoided. One should educate patients about early warning signs of liver injury. Always provide clinical and laboratory monitoring before and during the use of hepatotoxic drugs. Clinical features and laboratory results govern medication prescribing with ongoing risk-to-benefit ratio assessment during pharmacotherapy.

Structural alert/reactive metabolite concept as applied in medicinal chemistry to mitigate the risk of idiosyncratic drug toxicity: a perspective based on the critical examination of trends in the top 200 drugs marketed in the United States

Because of a preconceived notion that eliminating reactive metabolite (RM) formation with new drug candidates could mitigate the risk of idiosyncratic drug toxicity, the potential for RM formation is routinely examined as part of lead optimization efforts in drug discovery. Likewise, avoidance of "structural alerts" is almost a norm in drug design. However, there is a growing concern that the perceived safety hazards associated with structural alerts and/or RM screening tools as standalone predictors of toxicity risks may be over exaggerated. In addition, the multifactorial nature of idiosyncratic toxicity is now well recognized based upon observations that mechanisms other than RM formation (e.g., mitochondrial toxicity and inhibition of bile salt export pump (BSEP)) also can account for certain target organ toxicities. Hence, fundamental questions arise such as: When is a molecule that contains a structural alert (RM positive or negative) a cause for concern? Could the molecule in its parent form exert toxicity? Can a low dose drug candidate truly mitigate metabolism-dependent and -independent idiosyncratic toxicity risks? In an effort to address these questions, we have retrospectively examined 68 drugs (recalled or associated with a black box warning due to idiosyncratic toxicity) and the top 200 drugs (prescription and sales) in the United States in 2009 for trends in physiochemical characteristics, daily doses, presence of structural alerts, evidence for RM formation as well as toxicity mechanism(s) potentially mediated by parent drugs. Collectively, our analysis revealed that a significant proportion (∼78-86%) of drugs associated with toxicity contained structural alerts and evidence indicating that RM formation as a causative factor for toxicity has been presented in 62-69% of these molecules. In several cases, mitochondrial toxicity and BSEP inhibition mediated by parent drugs were also noted as potential causative factors. Most drugs were administered at daily doses exceeding several hundred milligrams. There was no obvious link between idiosyncratic toxicity and physicochemical properties such as molecular weight, lipophilicity, etc. Approximately half of the top 200 drugs for 2009 (prescription and sales) also contained one or more alerts in their chemical architecture, and many were found to be RM-positive. Several instances of BSEP and mitochondrial liabilities were also noted with agents in the top 200 category. However, with relatively few exceptions, the vast majority of these drugs are rarely associated with idiosyncratic toxicity, despite years of patient use. The major differentiating factor appeared to be the daily dose; most of the drugs in the top 200 list are administered at low daily doses. In addition, competing detoxication pathways and/or alternate nonmetabolic clearance routes provided suitable justifications for the safety records of RM-positive drugs in the top 200 category. Thus, while RM elimination may be a useful and pragmatic starting point in mitigating idiosyncratic toxicity risks, our analysis suggests a need for a more integrated screening paradigm for chemical hazard identification in drug discovery. Thus, in addition to a detailed assessment of RM formation potential (in relationship to the overall elimination mechanisms of the compound(s)) for lead compounds, effects on cellular health (e.g., cytotoxicity assays), BSEP inhibition, and mitochondrial toxicity are the recommended suite of assays to characterize compound liabilities. However, the prospective use of such data in compound selection will require further validation of the cellular assays using marketed agents. Until we gain a better understanding of the pathophysiological mechanisms associated with idiosyncratic toxicities, improving pharmacokinetics and intrinsic potency as means of decreasing the dose size and the associated "body burden" of the parent drug and its metabolites will remain an overarching goal in drug discovery.

In vitro assessment of mitochondrial dysfunction and cytotoxicity of nefazodone, trazodone, and buspirone

Mitochondrial toxicity is increasingly implicated in a host of drug-induced organ toxicities, including hepatotoxicity. Nefazodone was withdrawn from the U.S. market in 2004 due to hepatotoxicity. Accordingly, we evaluated nefazodone, another triazolopyridine trazodone, plus the azaspirodecanedione buspirone, for cytotoxicity and effects on mitochondrial function. In accord with its clinical disposition, nefazodone was the most toxic compound of the three, trazodone had relatively modest effects, whereas buspirone showed the least toxicity. Nefazodone profoundly inhibited mitochondrial respiration in isolated rat liver mitochondria and in intact HepG2 cells where this was accompanied by simultaneous acceleration of glycolysis. Using immunocaptured oxidative phosphorylation (OXPHOS) complexes, we identified Complex 1, and to a lesser amount Complex IV, as the targets of nefazodone toxicity. No inhibition was found for trazodone, and buspirone showed 3.4-fold less inhibition of OXPHOS Complex 1 than nefazodone. In human hepatocytes that express cytochrome P450, isoform 3A4, after 24 h exposure, nefazodone and trazodone collapsed mitochondrial membrane potential, and imposed oxidative stress, as detected via glutathione depletion, leading to cell death. Our results suggest that the mitochondrial impairment imposed by nefazodone is profound and likely contributes to its hepatotoxicity, especially in patients cotreated with other drugs with mitochondrial liabilities.

Toxicogenomics and classic toxicology: how to improve prediction and mechanistic understanding of human toxicity

The field of toxicogenomics has been advancing during the past decade or so since its origin. Most pharmaceutical companies are using it in one or more ways to improve their productivity and supplement their classic toxicology studies. Acceptance of toxicogenomics will continue to grow as regulatory concerns are addressed, proof of concept studies are disseminated more fully, and internal case studies show value for the use of this new technology in concert with classic testing.

Computational chemistry approach for the early detection of drug-induced idiosyncratic liver toxicity

Idiosyncratic drug toxicity (IDT), considered as a toxic host-dependent event, with an apparent lack of dose response relationship, is usually not predictable from early phases of clinical trials, representing a particularly confounding complication in drug development. Albeit a rare event (usually <1/5000), IDT is often life threatening and is one of the major reasons new drugs never reach the market or are withdrawn post marketing. Computational methodologies, like the computer-based approach proposed in the present study, can play an important role in addressing IDT in early drug discovery. We report for the first time a systematic evaluation of classification models to predict idiosyncratic hepatotoxicity based on linear discriminant analysis (LDA), artificial neural networks (ANN), and machine learning algorithms (OneR) in conjunction with a 3D molecular structure representation and feature selection methods. These modeling techniques (LDA, feature selection to prevent over-fitting and multicollinearity, ANN to capture nonlinear relationships in the data, as well as the simple OneR classifier) were found to produce QSTR models with satisfactory internal cross-validation statistics and predictivity on an external subset of chemicals. More specifically, the models reached values of accuracy/sensitivity/specificity over 84%/78%/90%, respectively in the training series along with predictivity values ranging from ca. 78 to 86% of correctly classified drugs. An LDA-based desirability analysis was carried out in order to select the levels of the predictor variables needed to trigger the more desirable drug, i.e. the drug with lower potential for idiosyncratic hepatotoxicity. Finally, two external test sets were used to evaluate the ability of the models in discriminating toxic from nontoxic structurally and pharmacologically related drugs and the ability of the best model (LDA) in detecting potential idiosyncratic hepatotoxic drugs, respectively. The computational approach proposed here can be considered as a useful tool in early IDT prognosis.

The safety and efficacy of IFN-beta products for the treatment of multiple sclerosis

Multiple sclerosis, a chronic demyelinating disease of the CNS, is now a treatable disease. Phase III clinical trials of three recombinant IFN-beta products conducted in relapsing-remitting multiple sclerosis have shown, albeit modest, significant effects on relapses and short-term progression of disability, and a more substantial effect on MRI parameters. However, these effects do not correlate well with clinical disease activity or long-term disability. Overall, IFN-beta is safe and generally well tolerated, and reported adverse events were comparable between preparations. Systemic side effects can be effectively managed by dose escalation, use of an auto-injector and careful clinical monitoring.

Complete profiling and characterization of in vitro nefazodone metabolites using two different tandem mass spectrometric platforms

This paper describes the complete profiling and characterization of in vitro metabolites of the antidepressant agent nefazodone (NEF) generated by human liver microsome (HLM). Two new metabolic pathways (biotransformation) for NEF have been discovered by the characterization of three new metabolites, including two new metabolites (M24, M25) formed due to the N-dealkylation reaction that occurred between the triazolone and propyl units, and one new metabolite (M26) formed due to the O-dearylation reaction that occurred on the phenoxyethyl unit. These metabolites were initially detected by a 4000 Q-Trap instrument and then confirmed by exact mass measurement using an LTQ-Orbitrap. Both instruments proved to be capable of providing complete in vitro metabolite information in a single liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis, although each had its advantages and disadvantages. One noticeable disadvantage of the 4000 Q-Trap was the reduced quality of isotopic pattern in the enhanced mass scan (EMS) spectrum when it was used as survey scan to trigger multiple dependent product ion scans. The problem was especially exacerbated for minor metabolites with low signal intensity. On the other hand, the LTQ-Orbitrap maintained excellent isotopic pattern when used as a full scan survey scan. Twenty-six metabolites were detected and identified. The formation of these new metabolites was also confirmed by analyzing duplicate incubations at different time points.

Emerging treatments for depression

Established treatments for depression are often effective. However, a significant number of patients show limited or no response. With advancements in the explanation of the underlying neurobiology of depression, several novel therapeutic approaches have been developed. Emerging drug targets include novel monoamine oxidase inhibitors, triple monoamine re-uptake inhibitors, omega-3 fatty acids, melatoninergic agonists and receptor antagonists for corticotropin-releasing factor(1), glucocorticoid, substance-P and NMDA. Developments in therapeutic focal brain stimulation include vagus nerve stimulation, transcranial magnetic stimulation, magnetic seizure therapy and deep brain stimulation. The role of psychotherapy, both as monotherapy and as adjunctive therapy, is an active avenue of investigation. Although data on these treatments are limited, preliminary results are encouraging. A major goal that remains to be achieved is the identification of predictors of response to the various antidepressant treatments that have diverse mechanisms of action.

An overview of psychiatric issues in liver disease for the consultation-liaison psychiatrist

Liver disease is a common cause of morbidity and mortality in the United States and elsewhere. Arising from infectious, hereditary, or toxin-induced sources, the detection of liver disease often requires a high index of suspicion. Clinical presentations are highly variable and are often accompanied by neuropsychiatric symptoms. This fact, along with an increased incidence of liver disease among patients with primary psychiatric disorders and the presence of varied drug use, complicates the tasks of providing care to patients with liver disease. To assist the consultation-liaison psychiatrist, the authors present the first of a two-part series focused on psychiatric issues in liver disease.

Inhibition of Hepatobiliary Transport as a Predictive Method for Clinical Hepatotoxicity of Nefazodone

Treatment with the antidepressant nefazodone has been associated with clinical idiosyncratic hepatotoxicty. Using membranes expressing human bile salt export pump (BSEP), human sandwich hepatocytes, and intact rats, we compared nefazodone and its marketed analogs, buspirone and trazodone. We found that nefazodone caused a strong inhibition of BSEP (IC(50) = 9 microM), inhibition of taurocholate efflux in human hepatocytes (IC(50) = 14 microM), and a transient increase in rat serum bile acids 1 h after oral drug administration. Buspirone or trazodone had no effect on biliary transport system. Nefazodone produced time- and concentration-dependent toxicity in human hepatocytes with IC(50) = 18 microM and 30 microM measured by inhibition of protein synthesis after 6 h and 24 h incubation, respectively. Toxicity was correlated with the amount of unmetabolized nefazodone. Partial recovery in toxicity by 24 h has been associated with metabolism of nefazodone to sulfate and glucuronide conjugates. The saturation of nefazodone metabolism resulted in sustained decrease in protein synthesis and cell death at 50 microM. The toxicity was not observed with buspirone or trazodone. Addition of 1-aminobenzotriazole (ABT), an inhibitor of CYP450, resulted in enhancement of nefazodone toxicity at 10 microM and was associated with accumulation of unmetabolized nefazodone. In human liver microsomes, ABT also prevented metabolism of nefazodone and formation of glutathione conjugates. We suggest that inhibition of bile acid transport by nefazodone is an indicator of potential hepatotoxicity. Our findings are consistent with the clinical experience and suggest that described methodology can be applied in the selection of nonhepatotoxic drug candidates.

Advances in the treatment of depression

SUMMARY

Depression is a highly prevalent and disabling condition associated with significant morbidity and mortality. Currently available treatments for depression include tricyclic antidepressants, monoamine oxidase inhibitors, selective serotonin reuptake inhibitors, serotonin norepinephrine reuptake inhibitors, various atypical antidepressants, and electroconvulsive therapy. Although these treatments are effective, a significant number of patients do not respond or achieve sustained remission despite aggressive management. Advances in the neurobiology of depression have suggested a number of novel targets for antidepressant treatment. Based on an improved understanding of the neurobiology of depression, several novel pharmacologic and nonpharmacologic interventions are being developed. Pharmacologic developments include CRF antagonists, glucocorticoid receptor antagonists, substance P receptor antagonists, NMDA glutamate receptor antagonists, transdermal selegiline, so-called "triple" reuptake inhibitors, and augmentation of typical antidepressant medications with atypical antipsychotics. Nonpharmacologic advances have largely involved focal brain stimulation techniques including vagus nerve stimulation, transcranial magnetic stimulation, magnetic seizure therapy, and deep brain stimulation. For the most part, the data on these treatments are preliminary, and more study is needed to clarify their potential clinical benefit. However, it is clear that further study of the neurobiology of depression will continue to provide a rationale for developing innovative targets for antidepressant therapies.

Metabolic activation of the nontricyclic antidepressant trazodone to electrophilic quinone-imine and epoxide intermediates in human liver microsomes and recombinant P4503A4

Therapy with the antidepressant trazodone has been associated with several cases of idiosyncratic hepatotoxicity. While the mechanism of hepatotoxicity remains unknown, it is possible that reactive metabolites of trazodone play a causative role. Studies were initiated to determine whether trazodone undergoes bioactivation in human liver microsomes to electrophilic intermediates. LC/MS/MS analysis of incubations containing trazodone and NADPH-supplemented microsomes or recombinant P4503A4 in the presence of glutathione revealed the formation of conjugates derived from the addition of the sulfydryl nucleophile to mono-hydroxylated- and hydrated-trazodone metabolites. Product ion spectra suggested that mono-hydroxylation and sulfydryl conjugation occurred on the 3-chlorophenyl-ring, whereas hydration and subsequent sulfydryl conjugation had occurred on the triazolopyridinone ring system. These findings are consistent with bioactivation sequences involving: (1) aromatic hydroxylation of the 3-chlorophenyl-ring in trazodone followed by the two-electron oxidation of this metabolite to a reactive quinone-imine intermediate, which reacts with glutathione in a 1,4-Michael fashion and (2) oxidation of the pyridinone ring to an electrophilic epoxide, ring opening of which, by glutathione or water generates the corresponding hydrated-trazodone-thiol conjugate or the stable diol metabolite, respectively. The pathway involving trazodone bioactivation to the quinone-imine has also been observed with many para-hydroxyanilines including the structurally related antidepressant nefazodone. It is proposed that the quinone-imine and/or the epoxide intermediate(s) may represent a rate-limiting step in the initiation of trazodone-mediated hepatotoxicity.

BIOACTIVATION OF THE NONTRICYCLIC ANTIDEPRESSANT NEFAZODONE TO A REACTIVE QUINONE-IMINE SPECIES IN HUMAN LIVER MICROSOMES AND RECOMBINANT CYTOCHROME P450 3A4

The therapeutic benefits of the antidepressant nefazodone have been hampered by several cases of acute hepatotoxicity/liver failure. Although the mechanism of hepatotoxicity remains unknown, it is possible that reactive metabolites of nefazodone play a causative role. Studies were initiated to determine whether nefazodone undergoes bioactivation in human liver microsomes to electrophilic intermediates. Following incubation of nefazodone with microsomes or recombinant P4503A4 in the presence of sulfydryl nucleophiles, conjugates derived from the addition of thiol to a monohydroxylated nefazodone metabolite were observed. Product ion spectra suggested that hydroxylation and sulfydryl conjugation occurred on the 3-chlorophenylpiperazine-ring, consistent with a bioactivation pathway involving initial formation of p-hydroxynefazodone, followed by its two-electron oxidation to the reactive quinone-imine intermediate. The formation of novel N-dearylated nefazodone metabolites was also discernible in these incubations, and 2-chloro-1,4-benzoquinone, a by-product of N-dearylation, was trapped with glutathione to afford the corresponding hydroquinone-sulfydryl adduct. Nefazodone also displayed NADPH-, time-, and concentration-dependent inactivation of P4503A4 activity, suggesting that reactive metabolites derived from nefazodone bioactivation are capable of covalently modifying P4503A4. A causative role for 2-chloro-1,4-benzoquinone and/or the quinone-imine intermediate(s) in nefazodone hepatotoxicity is speculated. Although the antianxiety agent buspirone, which contains a pyrimidine ring in place of the 3-chlorophenyl-ring, also generated p-hydroxybuspirone in liver microsomes, no sulfydryl conjugates of this metabolite were observed. This finding is consistent with the proposal that two-electron oxidation of p-hydroxybuspirone to the corresponding quinone-imine is less favorable due to differences in the protonation state at physiological pH and due to weaker resonance stabilization of the oxidation products as predicted from ab initio measurements.

Studies on the Human Metabolism and the Toxicologic Detection of the Cough Suppressant Dropropizine in Urine Using Gas Chromatography-Mass Spectrometry

Studies are described on the metabolism and the toxicologic analysis of the nonopioid cough suppressant dropropizine [R,S-3-(4-phenyl-1-piperazinyl)1,2-propandiol, DRO] in human urine using gas chromatography-mass spectrometry (GC-MS). The metabolism studies showed that DRO was metabolized in humans mainly by hydroxylation of the aromatic ring, by N-dealkylation of the parent drug and of the hydroxyl-metabolite to the corresponding N-phenylpiperazines, and by degradation of the piperazine moiety. The authors' systematic toxicologic analysis (STA) procedure using full-scan GC-MS after acid hydrolysis, liquid-liquid extraction, and microwave-assisted acetylation allowed the unambiguous detection of DRO and its above-mentioned metabolites in human urine up to about 32 hours after intake of a single common therapeutic dose. The target analytes were found to be the parent compound DRO (earlier phase of excretion) and the hydroxylated metabolite para-hydroxy-DRO (later phase of excretion). Both allowed unambiguous detection of an intake of DRO and also differentiation from other phenylpiperazine derivatives.

A placebo-controlled study of nefazodone for the treatment of chronic posttraumatic stress disorder: a preliminary study

Nefazodone is a unique serotonergic antidepressant that acts as both a presynaptic serotonin reuptake inhibitor and a postsynaptic 5-hydroxytryptamine 2A receptor antagonist. Based on the positive results of open-label trials of nefazodone, including one from our group, we tested nefazodone's efficacy in the treatment of posttraumatic stress disorder (PTSD) under placebo-controlled conditions. Forty-one patients with chronic PTSD, predominantly male combat veterans, were enrolled in a randomized, double-blind, placebo-controlled 12-week trial of nefazodone. The primary outcome measure was the Clinician-Administered PTSD Scale. Fifteen patients were randomized to placebo and 26 were randomized to nefazodone. In a repeated-measures analysis of variance with last observation carried forward, patients on nefazodone showed a significant improvement in the percentage change of Clinician-Administered PTSD Scale Total score from baseline compared with those on placebo (P = 0.04; effect size = 0.6). Sample size was not powered to test group differences in the Clinician-Administered PTSD Scale criterion B, C, or D subscale. However, the criterion D subscale showed significant improvement in patients treated with nefazodone compared with those treated with placebo (P = 0.007). In addition, the Hamilton Rating Scale for Depression showed significant improvement compared with placebo (P = 0.008). The nefazodone group also reported an improvement on the PTSD Checklist (self-report scale; P = 0.08) and the Clinician-Administered Dissociative States Scale (P = 0.06). This pilot study supports the efficacy of nefazodone for the treatment of PTSD. However, larger placebo-controlled studies in more diverse patient population are warranted.

Hepatic reactions during treatment of multiple sclerosis with interferon-beta-1a: incidence and clinical significance

BACKGROUND

Hepatic dysfunction, manifested as liver enzyme elevations, occurs frequently in patients who are treated with interferon, however, data for patients with multiple sclerosis are limited.

OBJECTIVE

To retrospectively assess the safety profile of interferon-beta-1a therapy with respect to liver function during clinical trials and postmarketing surveillance in the treatment of multiple sclerosis.

PATIENTS AND METHODS

Adverse effects and laboratory abnormalities were analysed from six randomised, controlled clinical trials (five of which were placebo-controlled) that assessed the use of interferon-beta-1a in patients with multiple sclerosis. Treatment data were collected for 2819 patients for up to 12 months, of whom 1995 received interferon-beta-1a (337 [12%] received Avonex intramuscular therapy, and 1658 [59%] received Rebif subcutaneous therapy), and 824 (29%) received placebo. Data for 2 years were collated for 1178 patients (from two studies). Total weekly interferon doses were 22-132 microg. Postmarketing surveillance data were also analysed.

RESULTS

In patients receiving interferon-beta-1a, there were significant elevations of alanine aminotransferase (ALT) levels, of all grades of severity, in up to 59% of patients at 6 months, up to 64% of patients at 12 months and up to 67% of patients at 24 months; ALT elevations were asymptomatic and dose related. More than 50% of elevations in liver enzymes occurred during the first 3 months of treatment, and more than 75% occurred during the first 6 months. Elevated enzyme levels resolved spontaneously or with dosage adjustment. Although the overall incidence of liver enzyme elevation was high during the early months of therapy, after 2 years, the proportion of patients with abnormal liver enzyme levels was 11% of those receiving Rebif 44 microg three times weekly compared with 6% of placebo-treated patients. Only 0.4% of patients discontinued interferon-beta-1a treatment because of hepatic adverse effects. Serious symptomatic interferon-related hepatic toxicity occurs, but is uncommon. Concomitant medication use was not associated with increased risk.

CONCLUSION

Asymptomatic hepatic dysfunction is common in patients with multiple sclerosis who are treated with interferon-beta-1a, and is dose related. Adverse effects are mainly mild and transient, with little impact on adherence to therapy, although rare serious events can occur. Regular liver function monitoring during the first 6 months is recommended.

Hepatic injury and pancreatitis during treatment with serotonin reuptake inhibitors: data from the World Health Organization (WHO) database of adverse drug reactions

Severe hepatic adverse drug reactions have been occasionally reported in the literature for the selective serotonin reuptake inhibitors (SSRIs), venlafaxine and nefazodone. In addition, a few case reports have suggested a possible association between SSRI treatment and pancreatitis. To further investigate this issue, a Bayesian confidence propagation neural network (BCPNN) method was applied on the World Health Organization database of adverse drug reactions. This method identifies whether a drug/adverse drug reaction combination is reported more frequently to the database than expected on the basis of chance alone compared to general reporting in the database. A statistically significant unexpected high number of reports were found for nefazodone and hepatic injury, relative to the generality of the dataset but, for the other drug/adverse drug reaction combinations, no such association was found. The nefazodone finding is in accordance with data from other publications, suggesting that the risk of hepatic injury is increased. However, because of the nature of the BCPNN, the negative findings do not necessarily prove that there is no excess risk for hepatic injury/pancreatitis during treatment with drugs other than nefazodone. Further studies are required using alternative methodologies to demonstrate whether the selective serotonin reuptake inhibitors or venlafaxine may cause hepatic injury or pancreatitis.

Fulminant liver disease

Fulminant liver disease, acute liver failure (ALF), is one of the most intriguing and challenging conditions in the entire field of internal medicine. ALF is defined as the onset of hepatic encephalopathy and coagulopathy in patients with no known underlying liver disease within 8 to 26 weeks of onset of illness. Many cases develop within a few days, dramatically transforming an otherwise healthy individual to a patient with a high risk for developing multi-organ failure and death.

Antidepressant-induced hepatotoxicity

Depression is a chronic, severe and increasingly prevalent illness associated with substantial morbidity, mortality and healthcare costs. Antidepressant drugs, the cornerstone of depression treatment, are not devoid of adverse effects, including hepatotoxicity. To review the risk of liver toxicity related to major antidepressants, the authors have followed structural criteria focusing on the underlying mechanism presumably involved and the role of particular chemical structures. The clinicopathological expression goes from transient increases in liver enzymes to fulminant liver failure. Classical antidepressants such as monoamine oxidase inhibitors (MAOIs) or tricyclic antidepressants (TCAs) seem to have the highest potential to induce liver damage compared with the newer drugs such as selective serotonin re-uptake inhibitors (SSRIs). The potential for severe hepatotoxicity associated with nefazodone is stressed. Guidelines for therapy and prevention of antidepressant-induced hepatotoxicity are also discussed.

Comprehensive review of hepatitis C for psychiatrists: risks, screening, diagnosis, treatment, and interferon-based therapy complications

Hepatitis C is an RNA virus responsible for chronic infection in at least 4 million Americans. Patients are often unaware that they have contracted the virus until the appearance of long-term consequences of the infection, primarily cirrhosis and hepatocellular carcinoma. Many patients with hepatitis C have comorbid psychiatric and/or substance abuse disorders. Treatments for hepatitis C infection are based on interferon-alfa therapy and have shown increasing effectiveness in recent years; however, interferon-alfa therapy also poses significant risks for physical and neuropsychiatric side effects. Since psychiatrists often serve as primary caregivers for patients who are at higher risk for hepatitis C infection, knowledge about the diagnosis, prognosis, and treatment of this disease is needed. In the first half of this article, the authors review the epidemiology, transmission, pathophysiology and disease course of hepatitis C, as well as the neuropsychiatric complications of hepatitis C infection. They also discuss the incidence of comorbid psychiatric disorders in patients with hepatitis C infection and consider the impact of the infection on patients' quality of life. The authors then provide an overview of the clinical management of HCV infection, including screening procedures, decision-making about treatment, available treatments (interferon-alfa, pegylated interferon-alpha, combination therapy with interferon and ribavirin) and their side effects and potential drug-drug interactions, and prediction of treatment response. The authors then discuss management of the neuropsychiatric complications of treatment with interferon-alpha and ribavirin, including depression, mania and psychosis, and cognitive and neurological complications. The final section of the article focuses on special issues related to the treatment of hepatitis C infection in patients with substance abuse or dependence and/or other comorbid psychiatric illness.

A review of the common properties of drugs with idiosyncratic hepatotoxicity and the "multiple determinant hypothesis" for the manifestation of idiosyncratic drug toxicity

Idiosyncratic drug toxicity is generally believed to be a phenomenon that cannot be readily evaluated experimentally. Reasons for this difficulty include the following: 1. It is a rare event (<1/5,000) and therefore impossible to be studied in clinical trials; 2. It is a human-specific event not detectable in experimental animals. To aid the understanding of idiosyncratic toxicity and to develop an experimental strategy for this phenomenon, a hypothesis is proposed. The hypothesis states that the low frequency of idiosyncratic drug toxicity is due to the requirements for the occurrence of multiple critical and discrete events, with the probability for the occurrence of idiosyncratic drug toxicity as a product of the probabilities of each event. The key determinants of these critical events are proposed to be: 1. Chemical properties; 2. exposure; 3. environmental factors; and 4. genetic factors. Based on this hypothesis, idiosyncratic drug toxicity can be evaluated experimentally via studying these key determinants. The chemical properties critical to idiosyncratic drug toxicity are identified via a review of the common properties of drugs that cause idiosyncratic liver toxicity. These properties include: 1. Formation of reactive metabolites. 2. Metabolism by P450 isoforms. 3. Preponderance of P450 inducers, and 4. Occurrence of clinically significant pharmacokinetic interactions with co-administered drugs. Based on this review, it is proposed that these common properties may be useful experimental endpoints for the prediction and therefore avoidance of the selection of drug candidates with idiosyncratic drug toxicity for further development.

Nefazodone in the treatment of elderly patients with depressive disorders: a prospective, observational study

OBJECTIVES

The aim of this study was to evaluate the clinical effectiveness and tolerability of nefazodone for the treatment of depression in elderly patients in clinical routine practice.

PATIENTS AND STUDY DESIGN

Seventy-nine patients with a mean age of 72.81 years, who had major depression or dysthymia according to DSM-IV criteria, were enrolled into this open label study. Patients were prescribed nefazodone starting at 50 mg/day, increasing every 4 days until a dosage of 200 mg/day was attained, and subsequently upward to 600 mg/day if no dose-limiting adverse effects appeared. Effectiveness was evaluated at the end of weeks 2, 4, 8 and 12 by completion of the Hamilton Depression Rating Scale (HAM-D), the Geriatric Depression Scale (GDS) and the Clinical Global Impressions scale. The Hamilton Anxiety Rating Scale (HAM-A), the sleep satisfaction item of the Oviedo Sleep Questionnaire (OSQ) and the Short Portable Mental Status Questionnaire (SPMSQ) were used to assess the patients at the end of week 12. Primary efficacy analysis was based on an intention-to-treat, last-observation-carried-forward data set.

RESULTS

HAM-D scores decreased progressively from a baseline mean of 22.3 to 14.2 at the study endpoint; although this was a significant reduction, the endpoint score indicates that a significant residual symptomatology remained in the patients. Similarly, the GDS and HAM-A scores had decreased significantly by week 12. Response and remission rates were 47 and 37.5%, respectively. The percentage of patients who were satisfied, much satisfied or very much satisfied with their sleep according to the OSQ increased from 4.2% at baseline up to 62.2% at the study endpoint. A significant reduction in the SPMSQ total score was observed at the study endpoint, although the clinical relevance of this finding is doubtful. Forty-two (53.2%) patients completed the study. The most common reasons for withdrawal from the study were a lack of efficacy and adverse effects. Most adverse reactions were mild to moderate in severity and included dizziness, dry mouth, gastrointestinal distress, sedation, anxiety and malaise.

CONCLUSION

Our results suggest that nefazodone may be a well tolerated and effective alternative for treating elderly patients with depression. Although the HAM-D score at study endpoint indicated significant residual symptomatology, a similar finding has been described in several meta-analyses of antidepressant treatment in the elderly. Further research is needed to evaluate a different nefazodone dose regimen, especially a slower dose titration rate, which could result in a reduced discontinuation rate and thus a better treatment outcome.

Hepatic adverse reactions associated with nefazodone

OBJECTIVE

Since 1999, international reports of hepatotoxicity associated with the antidepressant nefazodone (Serzone) have increased. In June 2001, a manufacturer's safety advisory notified Canadian physicians of "very rare reports of severe liver injury temporally associated with the use of nefazodone HC1." We undertook this study to determine the prevalence of adverse drug reactions to nefazodone reported in a Canadian database.

METHOD

We requested the Canadian Adverse Drug Reaction Monitoring Programme (CADRMP) database for nefazodone and analyzed it for suspected hepatic complications reported and entered from the time of marketing to June 30, 2001.

RESULTS

We found 32 cases of liver injury associated with nefazodone, with 26 (81.3%) classified as "severe." Patients ranged in age from 30 to 69 years and took 100 to 600 mg of nefazodone daily. Most (68.8%) of the patients were women. Eleven patients were prescribed only nefazodone, and 20 took it concomitantly with other drugs. Of affected patients, 88% developed liver injury within 6 months of starting nefazodone. At the time of reporting, 17 patients recovered without sequelae, 12 patients had not yet recovered, and the outcomes for 3 were unknown. There were 3 cases of hepatic failure, 1 of hepatocellular degeneration, 1 of hepatic necrosis, and 1 of fulminant hepatitis.

CONCLUSION

In common with similar databases, the CADRMP database includes only a small proportion of suspected drug reactions. In view of 32 reported cases of hepatotoxicity associated with nefazodone in Canada, 81.3% of which were severe, caution should be exercised if nefazodone is prescribed with other drugs, especially those metabolized by CYP4503A4. Nefazodone should not be prescribed to patients with preexisting liver disease. Baseline and regular liver function tests should be obtained in all patients on nefazodone therapy in the first 6 months, and the drug should be discontinued if abnormalities are found. Patients should be advised of symptoms of hepatotoxicity, and to report them immediately to their physician.

Third-generation antidepressants: do they offer advantages over the SSRIs?

Third-generation antidepressants are a group of antidepressant agents of variable action, not confined to serotonin reuptake inhibition. These agents include venlafaxine, reboxetine, nefazodone and mirtazapine. Claims have been made for these agents in terms of improved efficacy, faster speed of onset of effect and greater safety in the treatment of depression compared with previous medications, such as the selective serotonin reuptake inhibitors (SSRIs). This article reviews the evidence for these improvements. Thirty active comparator studies were reviewed involving the third-generation antidepressant agents. While there were isolated reports of improvements over comparator agents for venlafaxine, reboxetine and mirtazepine, there were no convincing differences between third-generation agents and comparators in terms of overall efficacy, relapse prevention and speed of onset. The third-generation antidepressants were, however, of equivalent safety to SSRIs and maintained improvements in safety over first-generation agents.

Acute liver failure

Worldwide, viral hepatitis is the leading cause of acute liver failure, whereas acetaminophen hepatotoxicity is the most commonly identified cause in Western countries. Restricting the quantity of acetaminophen tablets dispensed has been shown to reduce morbidity and mortality in countries with a high incidence of acetaminophen overdose. Troglitazone and bromfenac are two recently approved medications that were withdrawn from the market due to an unacceptably high incidence of severe hepatotoxicity. In addition, trovafloxacin, nefazodone, and ritonavir were reported to be associated with severe hepatitis and acute liver failure. Moderate hypothermia is a simple and potentially effective means of reducing intracranial pressure in patients with acute liver failure and cerebral edema. However, controlled clinical trials are needed to determine proper patient selection and optimize treatment. Extracorporeal bioartificial liver support devices remain an exciting but as yet unproven means of supporting acute liver failure patients with advanced encephalopathy. Living donor liver transplantation has recently been reported for adults and children with acute liver failure. However, ethical concerns regarding donor safety and the ability to obtain informed consent without coercion have been raised. Lastly, advances in the identification and isolation of pluripotent liver stem cells in human bone marrow provides hope for a simple and effective means of enhancing native liver regeneration.

Drug-induced liver disease

The incidence of drug-induced liver disease appears to be increasing, reflecting the increasing number of new agents that have been introduced into clinical use over the past several decades. Among the topics covered, the author discusses incidence, diagnosis, risk factors, clinical presentations, hepatitis, and vascular injury. The author also reviews the hepatic injury seen with commonly prescribed drugs, emphasizing newer developments in the field and recent publications and reports.

The use of psychotropics in the medically ill

Underlying medical illness may present a challenge when prescribing psychotropic medications. Disease-related changes in pharmacokinetics and pharmacodynamics, as well as vulnerability to side effects, polypharmacy, and potential drug interactions are all important considerations. Successful treatment of psychiatric disorders may have a beneficial impact on medical morbidity and mortality, as well as quality of life. This article reviews the relevant considerations when using psychotropic medications in six major medical populations (cardiac, cerebral vascular, pulmonary, liver, renal, and seizure disorders).

Drug-induced liver disease

This year's review has been divided into five sections: The first describes the natural history of drug-induced liver disease, the second discusses the issue of placebo-related increases in liver-associated enzymes, the third describes agents newly reported to cause hepatic injury, the fourth discusses new reports of hepatic injury from established drugs, and the final section reviews the burgeoning field of hepatoprotection with clinical and experimental examples of agents used in the prevention and treatment of drug-induced liver disease, with acetaminophen as the major example.

SNaRIs, NaSSAs, and NaRIs: new agents for the treatment of depression

A major goal of antidepressant development is to improve on preceding drug classes with agents with greater specificity (and therefore fewer unwanted side-effects) and with more rapid onset of antidepressant action. To this end, four antidepressants with significantly distinct pharmacological characteristics have been recently introduced: venlafaxine, nefazodone, mirtazapine, and reboxetine. Venlafaxine is the first antidepressant in a new drug class referred to as the serotonin noradrenergic reuptake inhibitors (SNaRIs). Nefazodone is a weaker serotonin and norepinephrine reuptake inhibitor, but a potent serotonin 5-HT2 receptor antagonist. Mirtazapine is a potent antagonist of central 2alpha-adrenergic autoreceptors, and heteroreceptors and is an antagonist of serotonin 5-HT2 and 5-HT3 receptors. The result of these actions is to increase both noradrenergic and specific (5-HT1) serotonergic transmission, and mirtazapine has therefore been termed a noradrenergic and specific serotonergic antidepressant (NaSSA). Reboxetine is the first selective noradrenaline reuptake inhibitor (NaRI) to be introduced since the tricyclics, and lacks immediate serotonergic effects.

Liver Failure Associated with Flutamide and Nefazodone Liver Toxicity with Metformin and Acarbose Hypomanic Episode with St. John's Wort

The purpose of this feature is to heighten awareness of specific adverse drug reactions (ADRs), to discuss methods of prevention, and to promote reporting of ADRs to the FDA's medWatch program (1-800-FDA-1088). If you have reported an interesting preventable ADR to medWatch, please consider sharing the account with our readers.