Management of clozapine-related hepatotoxicity

Recognition and management of clozapine adverse effects: A systematic review and qualitative synthesis

OBJECTIVE

Clozapine is substantially underutilized in most countries and clinician factors including lack of knowledge and concerns about adverse drug effects (ADEs) contribute strongly to treatment reluctance. The aim of this systematic review was to provide clinicians with a comprehensive information source regarding clozapine ADEs.

METHODS

PubMed and Embase databases were searched for English language reviews concerned with clozapine ADEs; publications identified by the automated search were manually searched for additional relevant citations. Following exclusion of redundant and irrelevant reports, pertinent information was summarized in evidence tables corresponding to each of six major ADE domains; two authors reviewed all citations for each ADE domain and summarized their content by consensus in the corresponding evidence table. This study was conducted in accordance with PRISMA principles.

RESULTS

Primary and secondary searches identified a total of 305 unique reports, of which 152 were included in the qualitative synthesis. Most clozapine ADEs emerge within 3 months, and almost all appear within 6 months, after initiation. Notable exceptions are weight gain, diabetic ketoacidosis (DKA), severe clozapine-induced gastrointestinal hypomotility (CIGH), clozapine-induced cardiomyopathy (CICM), seizures, and clozapine-induced neutropenia (CIN). Most clozapine ADEs subside gradually or respond to dose reduction; those that prompt discontinuation generally do not preclude rechallenge. Rechallenge is generally inadvisable for clozapine-induced myocarditis (CIM), CICM, and clozapine-induced agranulocytosis (CIA). Clozapine plasma levels >600-1000 μg/L appear more likely to cause certain ADEs (e.g., seizures) and, although there is no clear toxicity threshold, risk/benefit ratios are generally unfavorable above 1000 μg/L.

CONCLUSION

Clozapine ADEs rarely require discontinuation.

Effects of several atypical antipsychotics closapine, sertindole or ziprasidone on hepatic antioxidant enzymes: Possible role in drug-induced liver dysfunction

Chronic use of atypical antipsychotics may produce hepatic damage. Atypical antipsychotics, including clozapine, sertindole, and ziprasidone, are extensively metabolized by the liver and this process generates toxic-free radical metabolic intermediates which may contribute to liver damage. The aim of this study was to investigate whether clozapine, sertindole, or ziprasidone affected hepatic antioxidant defense enzymes which consequently led to disturbed redox homeostasis. The expression and activity of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), and glutathione-S-transferases (GST) were measured in rat livers at doses corresponding to human antipsychotic therapy. Clozapine increased activity of SOD types 1 and 2, GR and GST, but reduced CAT activity. Sertindole elevated activities of both SODs. In ziprasidone-treated rats only decreased CAT activity was found. All three antipsychotics produced mild-to-moderate hepatic histopathological changes categorized as regenerative alterations. No apparent signs of immune cell infiltration, microvesicular or macrovesicular fatty change, or hepatocytes in mitosis were observed. In conclusion, a 4-week long daily treatment with clozapine, sertindole, or ziprasidone altered hepatic antioxidant enzyme activities and induced histopathological changes in liver. The most severe alterations were noted in clozapine-treated rats. Data indicate that redox disturbances may contribute to liver dysfunction after long-term atypical antipsychotic drug treatment.

Oxidation-reduction mechanisms in psychiatric disorders: A novel target for pharmacological intervention

While neurotransmitter dysfunction represents a key component in mental illnesses, there is now a wide agreement for a central pathophysiological hub that includes hormones, neuroinflammation, redox mechanisms as well as oxidative stress. With respect to oxidation-reduction (redox) mechanisms, preclinical and clinical evidence suggests that an imbalance in the pro/anti-oxidative homeostasis toward the increased production of substances with oxidizing potential may contribute to the etiology and manifestation of different psychiatric disorders. The substantial and continous demand for energy renders the brain highly susceptible to disturbances in its energy supply, especially following exposure to stressful events, which may lead to overproduction of reactive oxygen and nitrogen species under conditions of perturbed antioxidant defenses. This will eventually induce different molecular alterations, including extensive protein and lipid peroxidation, increased blood-brain barrier permeability and neuroinflammation, which may contribute to the changes in brain function and morphology observed in mental illnesses. This view may also reconcile different key concepts for psychiatric disorders, such as the neurodevelopmental origin of these diseases, as well as the vulnerability of selective cellular populations that are critical for specific functional abnormalities. The possibility to pharmacologically modulate the redox system is receiving increasing interest as a novel therapeutic strategy to counteract the detrimental effects of the unbalance in brain oxidative mechanisms. This review will describe the main mechanisms and mediators of the redox system and will examine the alterations of oxidative stress found in animal models of psychiatric disorders as well as in patients suffering from mental illnesses, such as schizophrenia and major depressive disorder. In addition, it will discuss studies that examined the effects of psychotropic drugs, including antipsychotics and antidepressants, on the oxidative balance as well as studies that investigated the effectiveness of a direct modulation of oxidative mechanisms in counteracting the behavioral and functional alterations associated with psychiatric disorders, which supports the promising role of the redox system as a novel therapeutic target for the improved treatment of brain disorders.

Aripiprazole-induced Hepatitis: A Case Report

Aripiprazole is an atypical antipsychotic that acts as a partial agonist of dopamine type 2 receptors as well as 5-HT1A receptors. It is used in the treatment of schizophrenia and in type 1 bipolar disorder for mania. Because aripiprazole is well tolerated with few side effects it is used off-label in other psychotic disorders. The prevalence of abnormal liver function tests with antipsychotic use is 32%, with clinically significant effects in 4% of cases. No cases of aripiprazole-induced liver injury have been published. We report a 28-year-old female who presented with non-affective first-episode psychosis and who was treated with aripiprazole. Initially she was medicated with 10 mg per day, with an increase to 20 mg per day on the 12th day of hospitalization. Nine days after she became icteric, with nausea and had a vomiting episode. Laboratory analysis revealed a very high level of alanine aminotransferase, and minor to moderately high levels of aspartate aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, and bilirubin. Aripiprazole was tapered and paliperidone was started with the improvement of clinical and laboratory findings.

Psychotropic drugs and liver disease: A critical review of pharmacokinetics and liver toxicity

The liver is the organ by which the majority of substances are metabolized, including psychotropic drugs. There are several pharmacokinetic changes in end-stage liver disease that can interfere with the metabolization of psychotropic drugs. This fact is particularly true in drugs with extensive first-pass metabolism, highly protein bound drugs and drugs depending on phase I hepatic metabolic reactions. Psychopharmacological agents are also associated with a risk of hepatotoxicity. The evidence is insufficient for definite conclusions regarding the prevalence and severity of psychiatric drug-induced liver injury. High-risk psychotropics are not advised when there is pre-existing liver disease, and after starting a psychotropic agent in a patient with hepatic impairment, frequent liver function/lesion monitoring is advised. The authors carefully review the pharmacokinetic disturbances induced by end-stage liver disease and the potential of psychopharmacological agents for liver toxicity.

Effects of haloperidol and clozapine administration on oxidative stress in rat brain, liver and serum

Antipsychotics remain the standard of care for individuals with schizophrenia, despite their association with adverse effects including extrapyramidal symptoms, metabolic syndrome and agranulocytosis. While the biological mechanisms underlying these side effects remain unresolved, it has been proposed that oxidative stress may play a role in their development. The aim of this study was to evaluate markers of oxidative stress associated with first- and second-generation antipsychotics, focusing on protein and lipid oxidation and expression of the antioxidant proteins peroxiredoxin-2 and peroxiredoxin-6. Following 28-day administration of haloperidol, clozapine or saline to adult rats, brain grey matter, white matter, serum and liver samples were obtained and lipid peroxidation, protein oxidation, peroxiredoxin-2 and peroxiredoxin-6 levels quantified. In grey matter, peroxiredoxin-6 was significantly increased in the haloperidol-exposed animals, with a trend towards increased lipid peroxidation also observed in this group. In liver, lipid peroxidation was increased in the clozapine-exposed animals, with a similar trend noted in the haloperidol group. Antipsychotics did not produce significant changes in serum or white matter. Our results suggest that haloperidol and clozapine may induce oxidative stress in brain and liver, respectively, consistent with the documented adverse effects of these agents.

Hepatotoxicity induced by clozapine: a case report and review of literature

Clozapine is an effective antipsychotic drug but is associated with serious side effects. Most treatment guidelines give no clear recommendations on regular monitoring of liver function tests, even though up to 60% of patients experience elevations in hepatic transaminases, with 15% to 30% experiencing an elevation two to three times greater than normal. Though elevations in liver function tests are often transient and asymptomatic, there are many reported cases of clozapine-induced hepatotoxicity, with damage to the liver, involvement of multiple organs, and even fulminant liver failure arising with moderate clozapine doses. This case report describes a Chinese woman who developed hepatotoxicity on a low dose of clozapine, and reviews the relevant literature.

Eosinophilia, pleural effusion, hepatitis, and jaundice occurring early in clozapine treatment

Clozapine use is associated with various adverse events, some of which have received little attention, including eosinophilia, pleural effusion, and hepatitis. Because of the fatality of jaundice with hepatitis, it is necessary to understand the course and management of clozapine-induced eosinophilia and hepatitis. We report on a case in which the eosinophil count began to increase shortly after clozapine use, and pleural effusion and fever then developed at the time eosinophilia was at its peak level. Jaundice with hepatitis consecutively developed when all the above symptoms subsided. The liver function recovered rapidly after clozapine was discontinued. We recommend that patients who develop rapid eosinophilia at the beginning of clozapine treatment should be monitored with LFTs, chest X-rays, and urine analysis tests.