Reversible nefazodone-induced liver failure

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.

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.

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.

Sexual dysfunction and psychotropic medications

Psychotropic drugs are often associated with sexual dysfunction. The frequency of antidepressant-associated sexual dysfunction is greatly underestimated in clinical trials that rely on patient self-report of these adverse events. Direct inquiry reveals that delayed orgasm/ejaculation occurs in >50% and anorgasmia in at least one third of patients given selective serotonin reuptake inhibitors. Antidepressant-induced sexual dysfunction can be successfully managed. A different antidepressant without significant sexual effects, such as bupropion or mirtazapine, can often be substituted. Other strategies involve drug holidays or adjunctive therapy with drugs such as sildenafil. Dopamine antagonist antipsychotic drugs are most commonly associated with decreased libido. The newer atypical antipsychotics, with less effect on dopamine, are less commonly associated with sexual dysfunction. Sexual dysfunction is commonly reported with seizure disorders, and many anticonvulsant drugs affect levels of sex hormones. Because sexual dysfunction can be related to many factors, care must be taken to establish the patient's baseline sexual functioning before the initiation of psychotropic drug therapy and to rule out other etiologies before drugs are implicated as causative.

Treatment of Anxiety and Depression in Transplant Patients

Depressive and anxiety disorders appear during the transplant process due to psychological stressors, medications and physiological disturbances. Treatment is necessary to prevent impact on patient compliance, morbidity and mortality. Psychotropic medications provide an effective option, although most are only available as oral formulations. Because of this, they are more susceptible to alterations in pharmacokinetic behaviour arising from organ dysfunction in the pretransplant period. Kinetics are also an issue when considering potential drug-drug interactions before and after transplantation. Prior to transplant, organ dysfunction can change the pharmacokinetic behaviour of some psychotropic agents, requiring adjustment of dosage and schedules. Thoracic or abdominal organ failure may reduce drug absorption through disturbances in intestinal motility, perfusion and function. Cirrhotic patients experience increased drug bioavailability due to portosystemic shunting, and thus dosage is adjusted downward. In contrast, dosage needs to be raised when peripheral oedema expands the drug distribution volume for hydrophilic and protein-bound agents. Drug clearance for most psychotropic medications is dependent upon hepatic metabolism, which is often disrupted by endstage organ disease. Selection of drugs or their dosage may need to be adjusted to lower the risk of drug accumulation. Further adjustments in dosage may be called for when renal failure accompanies thoracic or abdominal organ failure, resulting in further impairment of clearance. Studies regarding the treatment of anxiety and depressive disorders in the medically ill are limited in number, but recommendations are possible by review of clinical and pharmacokinetic data. Selective serotonin reuptake inhibitors are well tolerated and efficacious for depression, panic disorder and post-traumatic stress disorder. Adjustments in dosage are required when renal or hepatic impairment is present. Among them, citalopram and escitalopram appear to have the least risk of drug-drug interactions. Paroxetine has demonstrated evidence supporting its use with generalised anxiety disorder. Venlafaxine is an alternative option, beneficial in depression, post-traumatic stress and generalised anxiety disorders. Nefazodone may also be considered, but there is some risk of hepatotoxicity and interactions with immunosuppressant drugs. Mirtazapine still needs to be studied further in anxiety disorders, but can be helpful for depression accompanied by anorexia and insomnia. Bupropion is effective in the treatment of depression, but data are sparse about its use in anxiety disorders. Psychostimulants are a unique approach if rapid onset of antidepressant action is desired. Acute or short-term anxiolysis is obtained with benzodiazepines, and selection of particular agents entails consideration of distribution rate, half-life and metabolic route.

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.

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.

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.

Drug-induced liver disease

This year's review is divided into several sections: the first describes drug withdrawals and new general reviews of drug-induced liver disease (DILD), including a review of a classification of drug injury. We review agents newly described as causing DILD, and new reports of DILD from established agents appearing in the year 2000. New aspects regarding the treatment of acetaminophen toxicity are included, and in the final section we deal with prevention of DILD as well as issues surrounding the use of potentially hepatotoxic medications in patients with underlying chronic disease.

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.