Hepatic encephalopathy associated with combined clozapine and divalproex sodium treatment

Optimizing co-prescription of clozapine and antiseizure medications: a systematic review and expert recommendations for clinical practice

INTRODUCTION

Antiseizure medication (ASM) add-on to clozapine may be efficient to target clozapine-resistant mood or psychotic symptoms or clozapine-related adverse drug reactions (ADR) such as seizures. We aimed to synthesize the information relevant for clinical practice on the risks and benefits of clozapine-ASM co-prescription.

AREAS COVERED

Articles were identified with MEDLINE, Web of Sciences and PsycINFO search from inception through October 2023. The review was restricted to ASM with mood-stabilizing properties or with potential efficacy for resistant psychotic symptoms (valproate (VPA), lamotrigine, topiramate, carbamazepine, oxcarbazepine).

EXPERT OPINION

VPA add-on to clozapine is associated with a high risk of serious ADR (myocarditis, neutropenia, pneumonia) mostly explained by complex time-dependent drug-drug interactions. The initial inhibitory effects on clozapine metabolism require slow titration to avoid immuno-allergic reactions. After the titration period, VPA has mainly inductive effects on clozapine metabolism that are more marked in smokers requiring therapeutic drug monitoring. Lamotrigine and topiramate add-on may be recommended as the first-line treatment for clozapine-related seizures, but there is limited evidence regarding the efficacy of this strategy for clozapine-resistant psychotic symptoms. Carbamazepine should not be co-prescribed with clozapine because of its potential for agranulocytosis and for inducing clozapine metabolism.

Hepatitis, Interstitial Nephritis, and Pancreatitis in Association With Clozapine Treatment: A Systematic Review of Case Series and Reports

PURPOSE/BACKGROUND

Clozapine is the criterion standard in treatment-resistant schizophrenia. We sought to review data on several inflammatory effects associated with clozapine, specifically interstitial nephritis, hepatitis, and pancreatitis.

METHODS/PROCEDURES

We conducted a systematic review to identify studies, published up until December 2017, describing clozapine-induced hepatitis, nephritis, and pancreatitis. The primary objective was to characterize the clinical characteristics associated with each of the specific inflammatory reactions to clozapine.

FINDINGS/RESULTS

We identified 42 cases of inflammatory reactions associated with clozapine treatment- 20 :cases of clozapine-induced hepatitis, 11 cases of nephritis, and 11 of pancreatitis. The mean (SD) age was 38.8 (11.9) years. The mean (SD) dose of clozapine used was 252.4 (133.7) mg. Time to onset of pancreatitis (17.9 [11.2] days; range 4-35 days) was shorter than that for hepatitis (34.2 [20.1] days; range, 12-90 days) and nephritis (27.9 [27.0]; range, 8-90 days) but was not statistically significant (F = 2.267, P = 0.117). The mean (SD) time to recovery was shorter for cases of pancreatitis (15.7 [18.4] days) compared with cases of hepatitis (25.9 [16.5] days) and nephritis (24.5 [18.9] days). Three cases with hepatitis died. Seven of the cases had a clozapine rechallenge (hepatitis [n = 3], nephritis [n = 1], pancreatitis [n = 3]), with 5 having a recurrence at a mean (SD) onset of 3.5 (2.5) days (range, 1-7 days); 2 hepatitis cases were successfully rechallenged.

IMPLICATIONS/CONCLUSIONS

Clozapine-induced hepatitis, nephritis, and pancreatitis are uncommon adverse events, reflected in the paucity of case studies in the literature. Early recognition of the signs and symptoms of clozapine-associated hepatitis, nephritis, and pancreatitis is important, as when identified, clozapine should be urgently discontinued. Clozapine is associated with evidence of benign inflammatory processes; the extent to which hepatitis, and other inflammatory reactions, may be on a continuum with these more benign and self-limiting reactions is unclear, and this can only be resolved by prospectively following cohorts of clozapine-treated patients.

Hepatic Safety of Atypical Antipsychotics: Current Evidence and Future Directions

The newer atypical antipsychotic agents (AAPs) represent an attractive therapeutic option for a wide range of psychotic disorders, including schizophrenia and bipolar mania, because of the reduced risk of disabling extrapyramidal symptoms. However, their growing use has raised questions about their tolerability over the endocrine, metabolic, and cardiovascular axes. Indeed, atypical antipsychotic drugs are associated, to differing extents, with mild elevation of aminotransferases related to weight gain, AAP-induced metabolic syndrome, and nonalcoholic fatty liver disease. Although the hepatic safety of new AAPs seems improved over that of chlorpromazine, they can occasionally cause idiosyncratic liver injury with varying phenotypes and, rarely, lead to acute liver failure. However, AAPs are a group of heterogeneous, chemically unrelated compounds with distinct pharmacological and pharmacokinetic properties and substantially different safety profiles, which precludes the notion of a class effect for hepatotoxicity risk and highlights the need for an individualized therapeutic approach. We discuss the current evidence on the hepatotoxicity potential of AAPs, the emerging underlying mechanisms, and the limitations inherent to this group of drugs for both establishing a proper causality assessment and developing strategies for risk management.

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.

Seizure associated with clozapine: incidence, etiology, and management

Seizures are a known adverse effect of clozapine therapy. The literature varies on incidence rates of seizures, secondary to varying time frames in which each seizure occurred. Tonic-clonic seizures comprise the majority of seizures experienced secondary to clozapine use, but it is imperative to recognize the potential variety of seizure presentation. The exact etiology of clozapine-induced seizure is unknown. Conflicting reports regarding total oral dose, serum concentration, dose titration, and concomitant medications make it difficult to identify a single cause contributing to seizure risk. Following seizure occurrence, it may be in the best interests of the patient to continue clozapine treatment. In this clinical situation, the use of an antiepileptic drug (AED) for seizure prophylaxis may be required. The AED of choice appears to be valproate, but several successful case reports also support the use of lamotrigine, gabapentin and topiramate. Well-designed clinical trials regarding clozapine seizure prophylaxis are lacking. Given clozapine's strong evidence for efficacy in the treatment of schizophrenia and schizoaffective disorder, every attempt to manage side effects, including seizure, should be implemented to allow for therapeutic continuation.

Clozapine-induced fatal fulminant hepatic failure: a case report

Fulminant hepatic failure (FHF) refers to the rapid development of severe acute liver injury with impaired synthetic function and encephalopathy in a person who previously had a normal liver or had wellcompensated liver disease. The potential causes of FHF are numerous, but viral or toxin-induced hepatitis are the most common. Clozapineinduced hepatotoxicity has rarely been reported in the literature, occurs via an unknown mechanism and results in liver biochemical abnormalities that are usually of no clinical significance. In approximately 30% to 50% of patients treated with clozapine, there is an asymptomatic rise in serum aminotransaminase levels; however, there are no current guidelines for routine monitoring of liver function tests and liver enzymes during its use. Fatal fulminant hepatitis has only been reported in three patients receiving clozapine. A case of fatal FHF that occurred in a schizophrenic woman who began clozapine therapy shortly before her illness developed is described.

Somatic augmentation strategies in clozapine resistance--what facts?

BACKGROUND

Polypharmacy without evidence-based support is sometimes needed for patients treated with 40% to 70% clozapine who are clozapine nonresponders. Several somatic augmentation strategies are proposed in the scientific literature, with different levels of evidence for safety and efficacy.

OBJECTIVES

The purpose of the present study is to review the available literature on the efficacy and safety of clozapine augmentation with somatic agents other than antipsychotics. The following classes of agents are considered: (1) mood stabilizers, (2) antidepressants, (3) electroconvulsive therapy and repetitive transcranial magnetic stimulation, (4) glutamatergic agents, (5)fatty acids supplements, and (6) benzodiazepines.

RESULTS

Case controls and small-size clinical trials largely dominate the literature, limiting the power to draw conclusions concerning safety issues and the meaning of negative studies. Moreover, variable definitions of clozapine resistance, heterogeneous outcome measures, and short duration of treatment trials are additional limitations.

CONCLUSION

Generally, adjunctive strategies for clozapine-resistant patients remain based on scarce evidence of efficacy and significant safety concerns. Low-frequency repetitive transcranial magnetic stimulation, fatty acids supplements, and mirtazapine showed good tolerability and some efficacy, but the results need replication.

Augmentation strategies in clozapine-resistant schizophrenia

The introduction of antipsychotics in the 1950s revolutionised the treatment of schizophrenia, but it soon became apparent that a substantial number of patients demonstrated a suboptimal response to these antipsychotics. Clozapine proved to be beneficial in patients whose symptoms were treatment resistant, but it too had limitations, with as many as 40-70% of those treated with clozapine demonstrating inadequate response to this drug as well. The availability of other 'atypical' antipsychotics offers options, but clozapine appears to remain the most effective option in treatment-resistant schizophrenia. This, of course, raises the question of what to do when clozapine is only partially effective. To address the issue of treatment in patients who have demonstrated a suboptimal response to clozapine, efforts have focused on a variety of augmentation strategies, including numerous medications and electroconvulsive therapy. The current body of evidence consists largely of data from smaller open trials and case series/reports, although data from a limited number of controlled studies are now available. Not surprisingly, the evidence drawn from the former is more supportive of augmentation strategies, although the controlled trials are not without positive findings. The available information is certainly not so overwhelming as to endorse any single augmentation approach. Indeed, it argues for more controlled data and cautions us regarding the cost-benefit ratio in adopting this strategy. Over and above the added adverse effects of another treatment, there is evidence to indicate that actual clinical worsening can occur. Without compelling evidence, clinicians must resort to guiding principles. The potential benefits of augmentation cannot be ruled out, but it should be approached with caution and in a systematic fashion. Factors compromising clozapine response should first be ruled out, and any augmentation trials should be guided by existing evidence and a treatment plan that incorporates a clear understanding of target symptoms. A means of evaluating outcome effectively needs to be in place, and the trial should be circumscribed to prevent needless polypharmacy. A priori, an endpoint needs to be established and the trial discontinued unless results firmly support added benefits.

Liver function tests during treatment with antipsychotic drugs: a case series of 23 patients

Atypical antipsychotics represent a new class of medication for the treatment of schizophrenia and their use is associated with a reduction of neurological side effects. This article reports the result of the systematic clinical and biological supervision of hepatic enzymes on 23 schizophrenic inpatients treated by atypical antipsychotic during 2 weeks at Days 1 (D1), 7 (D7), and 14 (D14) in a naturalistic study during 6 months. The drug administrated was limited to four medications--risperidone, amisulpride, olanzapine, and clozapine--but other psychotropic agents were prescribed. Six cases of biological cytolytic hepatitis were observed. Due to the numerous risk factors and the frequency of "routine" conditions, careful supervision of the hepatic function is needed to prevent this kind of side effect.

Clozapine in bipolar disorder: treatment implications for other atypical antipsychotics

Traditional neuroleptics are often utilized clinically for the management of bipolar disorder. Although effective as antimanic agents, their mood stabilizing properties are less clear. Additionally, their acute clinical side effect profile and long term risk of tardive dyskinesia, particularly in mood disorder patients, portend significant liability. This review focuses on the use of atypical antipsychotics in the treatment of bipolar disorder focusing on clozapine as the prototypical agent. Although, preclinical research and clinical experience suggest that the atypical antipsychotics are distinctly different from typical antipsychotics, they themselves are heterogeneous in profiles of neuropharmacology, clinical efficacy, and tolerability. The early clinical experience of clozapine as a potential mood stabilizer suggests greater antimanic than antidepressant properties. Conversely, very preliminary clinical experience with risperidone suggests greater antidepressant than antimanic properties and some liability for triggering or exacerbating mania. Olanzapine and sertindole are under investigation in psychotic mood disorders. The foregoing agents and future drugs with atypical neuroleptic properties should come to play an increasingly important role, compared to the older classical neuroleptics, in the acute and long term management of bipolar disorder.