A review of the safety of clozapine during pregnancy and lactation

Overcoming clozapine's adverse events: a narrative review of systematic reviews and meta-analyses

INTRODUCTION

Clozapine is the gold standard treatment for treatment-resistant schizophrenia, however adverse events remain a clinical challenge.

AREAS COVERED

This review presents a narrative synthesis of systematic reviews and meta-analyses that have reported the onset, incidence, prevalence, and management of clozapine's adverse events. We conducted a systematic literature search using PubMed, Embase, PsycINFO, OvidMEDLINE, CINAHL, and the Cochrane Database of Systematic Reviews from inception to April 2024.

EXPERT OPINION

Effective management of clozapine's adverse events necessitates multi-faceted, individualized, and shared-decision strategies. Despite a lack of high-quality systematic evidence, expert inter-disciplinary solutions are provided to help address a critical need for clinical guidance. This 35-year update offers an evidence-based framework to assist clinicians, patients, and caregivers navigate the adverse events associated with clozapine therapy.

Clozapine-Induced Severe Toxicity: Exploring the Pharmacokinetic Profile of Clozapine and Its Significance in Hemodynamic Instability - A Case Report

Hemodynamic instability in patients with clozapine intoxication can indirectly reflect the serum concentration of clozapine.We have described a case of a 32-year-old pregnant woman who developed life-threatening clozapine toxicity at 28 weeks of gestation. The levels of clozapine and norclozapine in the serum were high. We initiated hemoperfusion(HP) and other detoxification therapies to remove the drug. The patient had severely dilated peripheral blood vessels, which led to cardiac symptoms such as fatal hypotension and uncontrollable tachycardia, resulting in very high cardiac output and elevated Central venous oxygen saturation (ScvO2). Pharmacological intervention significantly improved the hemodynamics.In light of our observations in the ongoing case, we posit that evaluating hemodynamic parameters before and after blood detoxification could serve as a valuable means to gauge effectiveness and provide guidance for treatment.

Prophylactic Management of Women With Bipolar Disorder During Pregnancy and the Perinatal Period: Clinical Scenario-Based Practical Recommendations From A Group of Perinatal Psychiatry Authors

ABSTRACT

Many women with bipolar disorder experience episodes of illness or relapses over the perinatal period, especially in the immediate postpartum period. Risks associated with treated/untreated psychopathologies and fetal exposure to bipolar medications make the management of bipolar disorder during these periods challenging for clinicians and patients. In light of the available effectiveness and reproductive safety data, the current clinical update based on the opinions of a group of international perinatal psychiatry authors recommends general considerations and specific management strategies for each possible clinical scenario, including mixed features, predominant polarity, diagnosis of subtypes of bipolar disorder, severity of previous episodes, and risk of recurrence of mood episodes.

Association of In Utero Antipsychotic Medication Exposure With Risk of Congenital Malformations in Nordic Countries and the US

Importance

Psychiatric disorders are common among female individuals of reproductive age. While antipsychotic medication use is increasing, the safety of such medications in pregnancy is an area with large evidence gaps.

Objective

To evaluate the risk of first-trimester antipsychotic exposure with respect to congenital malformations, focusing on individual drugs and specific malformation subtypes.

Design, Setting, and Participants

This cohort study used data from nationwide health registers from the 5 Nordic countries and the US and spanned 1996 to 2018. The Nordic cohort included all pregnancies resulting in singleton live-born infants, and the US cohort consisted of publicly insured mothers linked to their live-born infants nested in the nationwide Medicaid Analytic eXtract. Data were analyzed from November 2020 to April 2022.

Exposures

One or more first-trimester dispensing of any atypical, any typical, and individual antipsychotic drugs.

Main Outcomes and Measures

Any major congenital malformation and specific malformation subtypes previously suggested to be associated with antipsychotic exposure in utero: cardiovascular malformations, oral clefts, neural tube defects, hip dysplasia, limb reduction defects, anorectal atresia/stenosis, gastroschisis, hydrocephalus, other specific brain anomalies, and esophageal disorders. Propensity score stratification was used to control for potential confounders. Pooled adjusted estimates were calculated using indirect standardization.

Results

A total of 6 455 324 unexposed mothers (mean maternal age range across countries: 24-31 years), 21 751 mothers exposed to atypical antipsychotic drugs (mean age range, 26-31 years), and 6371 mothers exposed to typical antipsychotic drugs (mean age range, 27-32 years) were included in the study cohort. Prevalence of any major malformation was 2.7% (95% CI, 2.7%-2.8%) in unexposed infants, 4.3% (95% CI, 4.1%-4.6%) in infants with atypical antipsychotic drug exposure, and 3.1% (95% CI, 2.7%-3.5%) in infants with typical antipsychotic drug exposure in utero. Among the most prevalent exposure-outcome combinations, adjusted relative risks (aRR) were generally close to the null. One exception was olanzapine exposure and oral cleft (aRR, 2.1 [95% CI, 1.1-4.3]); however, estimates varied across sensitivity analyses. Among moderately prevalent combinations, increased risks were observed for gastroschisis and other specific brain anomalies after atypical antipsychotic exposure (aRR, 1.5 [95% CI, 0.8-2.6] and 1.9 [95% CI, 1.1-3.0]) and for cardiac malformations after chlorprothixene exposure (aRR, 1.6 [95% CI, 1.0-2.7]). While the association direction was consistent across sensitivity analyses, confidence intervals were wide, prohibiting firm conclusions.

Conclusions and Relevance

In this study, considering the evidence from primary and sensitivity analyses and inevitable statistical noise for very rare exposure-outcome combinations, in utero antipsychotic exposure generally was not meaningfully associated with an increased risk of malformations. The observed increased risks of oral clefts associated with olanzapine, gastroschisis, and other specific brain anomalies with atypical antipsychotics and cardiac malformations with chlorprothixene requires confirmation as evidence continues to accumulate.

Second to none: rationale, timing, and clinical management of clozapine use in schizophrenia

Despite its enduring relevance as the single most effective and important evidence-based treatment for schizophrenia, underutilization of clozapine remains considerable. To a substantial degree, this is attributable to a reluctance of psychiatrists to offer clozapine due to its relatively large side-effect burden and the complexity of its use. This underscores the necessity for continued education regarding both the vital nature and the intricacies of clozapine treatment. This narrative review summarizes all clinically relevant areas of evidence, which support clozapine's wide-ranging superior efficacy - for treatment-resistant schizophrenia (TRS) and beyond - and make its safe use eminently feasible. Converging evidence indicates that TRS constitutes a distinct albeit heterogeneous subgroup of schizophrenias primarily responsive to clozapine. Most importantly, the predominantly early onset of treatment resistance and the considerable decline in response rates associated with its delayed initiation make clozapine an essential treatment option throughout the course of illness, beginning with the first psychotic episode. To maximize patients' benefits, systematic early recognition efforts based on stringent use of TRS criteria, a timely offer of clozapine, thorough side-effect screening and management as well as consistent use of therapeutic drug monitoring and established augmentation strategies for suboptimal responders are crucial. To minimize permanent all-cause discontinuation, re-challenges after neutropenia or myocarditis should be considered. Owing to clozapine's unique efficacy, comorbid conditions including substance use and most somatic disorders should not dissuade but rather encourage clinicians to consider clozapine. Moreover, treatment decisions need to be informed by the late onset of clozapine's full effects, which for reduced suicidality and mortality rates may not even be readily apparent. Overall, the singular extent of its efficacy combined with the high level of patient satisfaction continues to distinguish clozapine from all other available antipsychotics.

A systematic review of maternal and infant outcomes after clozapine continuation in pregnancy

OBJECTIVE

While there is a general lack of evidence of the safety of antipsychotic medications in pregnancy, there is a specific reluctance to continue clozapine in treatment resistant patients who become pregnant. Our aim is to systematically review adverse maternal and infant outcomes following clozapine use during pregnancy.

METHOD

A systematic review of all observational and intervention studies which highlighted adverse maternal and infant outcomes following clozapine continuation in pregnancy was undertaken. Article selection and quality were independently assessed and PRISMA guidelines adhered to.

RESULTS

Of 481 studies identified only two studies met the inclusion criteria. Both were rated as poor quality. The first found no significant increase in any adverse maternal or infant outcomes associated with antipsychotic exposure, except an increased rate of low birth weight in antipsychotic exposed babies. The number of patients exposed to clozapine was too small for separate statistical analysis. The second study found higher APGAR scoring at one minute for the clozapine group, but the scores were not statistically different at five-minutes.

CONCLUSION

Limited evidence was found to show significant adverse maternal and infant outcomes in pregnancy following clozapine continuation.Key messagesLimited evidence to show that clozapine has adverse effects on mother and infant when used during pregnancy.Risk/benefit analysis should be done thoroughly for each individual patient regarding clozapine continuation when pregnancy is confirmed.Close monitoring of mother and infant during perinatal period when clozapine is continued.Further research is needed to more clearly define the effects of clozapine on mother and infant during pregnancy and into the postnatal period.

Schizophrenia

Schizophrenia, characterised by psychotic symptoms and in many cases social and occupational decline, remains an aetiological and therapeutic challenge. Contrary to popular belief, the disorder is modestly more common in men than in women. Nor is the outcome uniformly poor. A division of symptoms into positive, negative, and disorganisation syndromes is supported by factor analysis. Catatonic symptoms are not specific to schizophrenia and so-called first rank symptoms are no longer considered diagnostically important. Cognitive impairment is now recognised as a further clinical feature of the disorder. Lateral ventricular enlargement and brain volume reductions of around 2% are established findings. Brain functional changes occur in different subregions of the frontal cortex and might ultimately be understandable in terms of disturbed interaction among large-scale brain networks. Neurochemical disturbance, involving dopamine function and glutamatergic N-methyl-D-aspartate receptor function, is supported by indirect and direct evidence. The genetic contribution to schizophrenia is now recognised to be largely polygenic. Birth and early life factors also have an important aetiological role. The mainstay of treatment remains dopamine receptor-blocking drugs; a psychological intervention, cognitive behavioural therapy, has relatively small effects on symptoms. The idea that schizophrenia is better regarded as the extreme end of a continuum of psychotic symptoms is currently influential. Other areas of debate include cannabis and childhood adversity as causative factors, whether there is progressive brain change after onset, and the long-term success of early intervention initiatives.

Schizophrenia during pregnancy

PURPOSE OF REVIEW

A diagnosis of schizophrenia has significant implications for women of childbearing age, pregnant or considering a pregnancy, ranging from sexual health, psychopharmacological treatment, to the occurrence of negative pregnancy and foetal outcomes. We provide a short narrative review of recent papers focusing on these issues.

RECENT FINDINGS

Although pregnancy rates have been increasing in women with a diagnosis of schizophrenia, they also tend to have altogether fewer pregnancies and fewer live births than women without this diagnosis, and also higher rates of induced abortions.Use of antipsychotics in pregnancy has also increased, and evidence suggests lack of significant contraindications for their use in this period. However, drug levels monitoring may be recommended across the three trimesters, as levels may change in relation to pregnancy-related physiology.Monitoring of physical health is an increasingly crucial issue, given higher risk of gestational diabetes, negative obstetric and infant outcomes in these women.

SUMMARY

There is an urgent need to generate valid and reproducible research that could help implement appropriate treatment protocols and relapse-prevention approaches, and interventions based on strong pharmaceutical targets for the benefit of pregnant women with a diagnosis of schizophrenia, their families and their children.

An evaluation of the variation and underuse of clozapine in the United Kingdom

BACKGROUND

Clozapine is the only licensed treatment for treatment refractory schizophrenia. Despite this, it remains grossly underused relative to the prevalence of refractory schizophrenia. The extent of underuse and the degree of regional variation in prescribing in the United Kingdom is unknown. It is also unclear, how the UK compares with other European countries in rates of clozapine prescribing.

METHODS

We obtained data relating to all clozapine prescribing in the UK from the relevant clozapine registries. We examined regional variation in clozapine use across England, corrected for the known prevalence of severe mental illness (SMI). We also compared the UK rate of clozapine use per 100,000 population to that described in other European countries.

FINDINGS

There is substantial variation in clozapine prescribing across different regions of England and only about a third of potentially eligible patients were prescribed the drug in the UK. Clozapine prescribing rate in the UK was lower than in several European countries.

INTERPRETATION

There is clear regional inequity in access to the most effective treatment in refractory schizophrenia in England. Strategies to increase clozapine use, by overcoming both real and perceived barriers, are urgently necessary to reduce treatment inequity for patients with refractory schizophrenia.

Clozapine: An Updated Overview of Pharmacogenetic Biomarkers, Risks, and Safety-Particularities in the Context of COVID-19

BACKGROUND

clozapine (CLZ) use is precarious due to its neurological, cardiovascular, and hematological side effects; however, it is the gold standard in therapy-resistant schizophrenia (TRS) in adults and is underused.

OBJECTIVE

to examine the most recent CLZ data on (a) side effects concerning (b) recent pharmacological mechanisms, (c) therapy benefits, and (d) the particularities of the COVID-19 pandemic.

DATA SOURCES

a search was performed in two databases (PubMed and Web of Science) using the specific keywords "clozapine" and "schizophrenia", "side effects", "agranulocytosis", "TRS", or "bipolar affective disorder (BAF)" for the last ten years.

STUDY ELIGIBILITY CRITERIA

clinical trials on adults with acute symptoms of schizophrenia or related disorders.

RESULTS

we selected 37 studies, randomized controlled trials (RCTs), and clinical case series (CCS), centered on six main topics in the search area: (a) CLZ in schizophrenia, (b) CLZ in bipolar disorder, (c) side effects during the clozapine therapy, (d) CLZ in pregnancy, (e) CLZ in early-onset schizophrenia, and (f) CLZ therapy and COVID-19 infection.

LIMITATIONS

we considered RCTs and CCS from two databases, limited to the search topics. Conclusions and implications of key findings: (a) clozapine doses should be personalized for each patient based on pharmacogenetics testing when available; the genetic vulnerability postulates predictors of adverse reactions' severity; patients with a lower genetic risk could have less frequent hematological monitoring; (b) a CLZ-associated risk of pulmonary embolism imposes prophylactic measures for venous thromboembolism; (c) convulsive episodes are not an indication for stopping treatment; the plasma concentration of clozapine is a better side effect predictor than the dosage; (d) COVID-19 infection may enhance clozapine toxicity, generating an increased risk of pneumonia. Therapy must be continued with the proper monitoring of the white blood count, and the clozapine dose decreased by half until three days after the fever breaks; psychiatrists and healthcare providers must act together.

Association Between Gestational Diabetes and Mental Illness

The rates of both gestational diabetes mellitus (GDM) and mental illness in pregnancy are rising. There is an association between type 2 diabetes and major depressive disorder, anxiety and schizophrenia, thus there is a need for greater understanding of the relationship between GDM and mental illness. This review suggests that there is a bidirectional and complex relationship between antenatal depression, gestational diabetes and postpartum depression. The combined effect of both a history of depression and gestational diabetes significantly increases the risk of postpartum depression. There is an association between severe mental illness and GDM; however, it is strongly mediated by antipsychotic medications and psychosocial factors, in addition to the disease itself. Medication has a major role in treating mental illness during pregnancy and is not directly linked with GDM in either depression or psychosis. Health-care providers should be mindful of the association between GDM and mental illness to appropriately screen and treat both disorders.

Obstetric and neonatal outcomes of clozapine exposure in pregnancy: a consecutive case series

Clozapine is an effective antipsychotic that can lead to symptom resolution and functional recovery in patients with schizophrenia. Its available pregnancy safety data remain limited, which presents a challenge for clinicians managing women of reproductive age on clozapine. We retrospectively studied a consecutive case series of nine pregnancies where there was clozapine exposure. Our case series demonstrates that pregnant women on clozapine treatment can remain stable psychiatrically, but are vulnerable obstetrically, with high rates of obesity and gestational diabetes. Their babies also have poor neonatal adjustment, often requiring neonatal resuscitation. Furthermore, we report on clozapine-related side effects, changes in clozapine levels during pregnancy as well as variation in foetal wellbeing monitoring. These findings have implications for pregnancy care for women taking clozapine and require further exploration.

The association between hormones and antipsychotic use: a focus on postpartum and menopausal women

During the postpartum and menopausal periods of women's lives, there is a well-established and significant drop of circulating estrogens. This may be the reason why both these periods are associated with an increased risk for onset or exacerbation of psychiatric disorders. Whether symptoms are mainly affective or mainly psychotic, these disorders are frequently treated with antipsychotic medications, which calls for an examination of the relationship between hormone replacement and antipsychotic agents at these time periods. The aim of this narrative review is to summarize what is known about the association of hormones and antipsychotics in the postnatal period and at menopause. In the review, we focus on estrogen and oxytocin hormones and include, for the most part, only papers published within the last 10 years. Both estradiol and oxytocin have at various times been implicated in the etiology of postpartum disorders, and estrogens, sometimes combined with progesterone, have been tested as potential treatments for these conditions. The role of estradiol as an adjunct to antipsychotics in the prevention of postpartum relapses is currently controversial. With respect to oxytocin, studies are lacking. Psychosis in menopausal and postmenopausal women has been successfully treated with estrogens and selective estrogen-receptor modulators, mainly raloxifene, in addition to antipsychotics. Some symptoms appear to respond better than others. No oxytocin study has specifically targeted postmenopausal women. Because of feedback mechanisms, there is a theoretical danger of therapy with exogenous hormones interfering with endogenous secretion and disturbing the balance among inter-related hormones. When used with antipsychotics, hormones may also affect the metabolism and, hence, the brain level of specific antipsychotics. This makes treatment with antipsychotics plus hormones complicated. Dose, timing and route of intervention may all prove critical to efficacy. While much remains unknown, this literature review indicates that, within standard dose ranges, the combination of hormones and antipsychotics for postnatal and menopausal women suffering severe mental distress can be beneficial, and is safe.

Clozapine Use During Pregnancy and Lactation: A Case-Series Report

The current prescription of clozapine in psychotic women of reproductive age makes it crucial to understand its pharmacokinetics during pregnancy and lactation as well as its risk profile for neonatal outcome. The aim of this case series was to provide new evidence on the pharmacokinetic features of clozapine that determine its passage through the placenta and amniotic fluid, as well as the neonatal clozapine elimination half-life (t1/2). This case series demonstrates for the first time that clozapine might show partial placental passage similar to other atypical antipsychotics. Clozapine levels decreased during the first few days in nursing infants. The half-life of clozapine in neonates was slightly higher than previously estimated. Clozapine use in pregnancy may be associated with diabetes mellitus, especially if there is a family history of this disease. Although no acute toxicological effects were observed in the intrauterine exposed newborn, close follow-up of pregnancy is recommended. However, these results must be taken with caution being a case series with small sample size

Psychopharmacological treatment of schizophrenia during pregnancy and lactation

PURPOSE OF REVIEW

It is necessary, in every-day clinical life when treating pregnant women with mental diseases, to reach quick decisions derived from recent comprehensive information. The knowledge of the use of antipsychotics in pregnancy has increased considerably in the last years. This review tries to summarize important considerations and facilitate clinical decisions.

RECENT FINDINGS

This review will cover not only the effects of exposure during pregnancy on outcomes, postnatal adaption syndrome and lactation, but also pharmacokinetic considerations on the use of antipsychotics during pregnancy.

SUMMARY

The recent publications have found only minimally increased risks for certain malformations, after using ever more sophisticated statistical models of analysis and reassuring amounts of data. Taken together, the quality of the studies has greatly improved and the results are reassuring with respect to the safety of the use of antipsychotics during pregnancy. The rates of weight gain and gestational diabetes warrant closer attention in the clinical setting.