Clozapine and gastro-oesophageal reflux disease (GORD) - an investigation of temporal association

Antipsychotics and Medical Comorbidity: A Retrospective Study in an Urban Outpatient Psychiatry Clinic

Patients with psychotic disorders have increased rates of medical comorbidities. In this cross-sectional study, we investigated the relationship between antipsychotics and medical comorbidities among patients with psychotic disorders in an urban psychiatry clinic in Atlanta, Georgia (n = 860). Each antipsychotic group was compared to a group of patients from the same sample who were not on any antipsychotic, and logistic regression models were constructed for each comorbidity. Ziprasidone was associated with diabetes (aOR 2.56, 95% CI 1.03-6.38) and obesity (aOR 3.19, 95% CI 1.37-7.41). Aripiprazole was associated with obesity (aOR 2.39, 95% CI 1.27-4.51). Clozapine was associated with GERD (aOR 3.59, 95% CI 1.11-11.61), movement disorders (aOR 4.44, 95% CI 1.02-19.32), and arrythmias (4.89, 95% CI 1.44-16.64). Two antipsychotics that are considered weight neutral, ziprasidone and aripiprazole, were associated with cardiometabolic comorbidities. This study suggests that research is warranted to study the association between antipsychotics, medical comorbidity, and psychotic symptom burden.

Impact of CYP1A2, CYP2C19, and CYP2D6 genotype- and phenoconversion-predicted enzyme activity on clozapine exposure and symptom severity

Clozapine is an atypical antipsychotic metabolized by CYP1A2, CYP2D6, and CYP2C19 enzymes. Among 66 adult schizophrenia patients treated with clozapine-based combination therapies, we explored the impact of genotype-predicted CYP1A2, CYP2D6, and CYP2C19 activity on dose-adjusted clozapine concentrations and symptom severity, with and without correction for inhibitors and inducers of these enzymes. Uncorrected activity scores were not associated with dose-adjusted clozapine concentrations or symptom severity. CYP1A2 and CYP2D6 activity scores corrected for known inducers (i.e., smoking) and inhibitors (e.g., concomitant medications) were associated with dose-adjusted clozapine levels and in the case of CYP1A2, symptom severity. However, smoking status and certain inhibitors of clozapine metabolism (i.e., esomeprazole) explained significantly more variance in dose-adjusted clozapine levels relative to corrected activity scores. These findings highlight the clinical importance of nongenetic factors (smoking, concomitant medications) and suggest that the added utility of CYP1A2, CYP2D6, and CYP2C19 activity scores to guide clozapine dosing is currently limited.

Effects of Clozapine on the Gut: Cross-Sectional Study of Delayed Gastric Emptying and Small and Large Intestinal Dysmotility

BACKGROUND

Gastrointestinal hypomotility in people taking clozapine is common, poorly understood and potentially dangerous. It causes distress and sometimes sudden death, with greater associated morbidity than the better known adverse effect of clozapine, agranulocytosis. Neither the mechanism nor prevalence of clozapine-induced gastrointestinal hypomotility is well understood. Previous studies show clozapine impedes colon transit, likely owing to anticholinergic and anti-serotonergic properties. However, regional gastrointestinal transit times (including gastric and small bowel emptying) have not been quantified.

METHODS

We used wireless motility capsules to measure gastric emptying and small and large bowel transit times in clozapine-treated individuals. We tested 17 clozapine-treated patients without any known gastrointestinal dysfunction, and compared data with matched normative transit times.

RESULTS

Clozapine-treated participants had significant 'slow gut', with dysmotility in at least one region of the gastrointestinal tract evident in 82%, with 59% experiencing multi-regional dysmotility. Delayed gastric emptying was diagnosed in 41%, delayed small bowel transit in 71% and delayed colon transit in 50%. Only 18% of participants had normal studies. Hypomotility was not correlated with ethnicity, sex or duration of treatment. Subjective reporting of constipation had low sensitivity in predicting dysmotility. Delayed gastric emptying had been unrecognised clinically for all participants.

CONCLUSION

Clozapine is associated with significant multi-regional gastrointestinal dysfunction. This is relevant when considering the relationship between clozapine use and conditions such as gastroparesis, choking, aspiration pneumonia, constipation, ileus and intestinal pseudo-obstruction. While the constipating properties of clozapine are now well recognised, this study shows a high degree of vigilance is required for both lower and upper gastrointestinal dysmotility in people taking this antipsychotic.

A review of the nutritional challenges experienced by people living with severe mental illness: a role for dietitians in addressing physical health gaps

People experiencing a severe mental illness (SMI), such as schizophrenia, schizoaffective disorder, bipolar affective disorder or depression with psychotic features, have a 20-year mortality gap compared to the general population. This 'scandal of premature mortality' is primarily driven by preventable cardiometabolic disease, and recent research suggests that the mortality gap is widening. Multidisciplinary mental health teams often include psychiatrists, clinical psychologists, specialist mental health nurses, social workers and occupational therapists, offering a range of pharmacological and nonpharmacological treatments to enhance the recovery of clients who have experienced, or are experiencing a SMI. Until recently, lifestyle and life skills interventions targeting the poor physical health experienced by people living with SMI have not been offered in most routine clinical settings. Furthermore, there are calls to include dietary intervention as mainstream in psychiatry to enhance mental health recovery. With the integration of dietitians being a relatively new approach, it is important to review and assess the literature to inform practice. This review assesses the dietary challenges experienced by people with a SMI and discusses potential strategies for improving mental and physical health.

Potential Mechanisms of Hematological Adverse Drug Reactions in Patients Receiving Clozapine in Combination With Proton Pump Inhibitors

Clozapine is a second-generation antipsychotic which has proven efficacy in treating the symptoms of schizophrenia. Although clozapine therapy is associated with a number of adverse drug reactions, it is frequently used. One of the most common adverse drug reactions is gastroesophageal reflux disease which is an indication for treatment with proton pump inhibitors (PPIs). Coadministration of clozapine and PPIs increases the risk of hematological adverse drug reactions, including neutropenia and agranulocytosis. The mechanism in idiosyncratic agranulocytosis is not dose related and involves either a direct toxic or an immune-allergic effect. It is suspected that the clozapine metabolites nitrenium ion and N-desmethylclozapine may cause apoptosis or impair growth of granulocytes. Formation of N-desmethylclozapine is correlated with activity of the cytochrome P450 enzymes 1A2 and 3A4 (CYP1A2 and CYP3A4). Nitrenium ion is produced by the flavin-containing monooxygenase system of leukocytes. A drug interaction between clozapine and a PPI is a consequence of the induction of common metabolic pathways either by the PPI or clozapine. Findings to date suggest that indirect induction of flavin-containing monooxygenase by omeprazole through the aryl hydrocarbon receptor increases the expression of the enzyme mRNA and in the long term may cause the increase in activity. Moreover, induction of CYP1A2, especially by omeprazole and lansoprazole, may increase the serum concentration of N-desmethylclozapine, which can accumulate in lymphocytes and may achieve toxic levels. Another hypothesis that may explain hematological adverse drug reactions is competitive inhibition of CYP2C19, which may contribute to increased serum concentrations of toxic metabolites.

Dyspepsia and constipation in patients with schizophrenia spectrum disorders

Constipation and dyspepsia are disturbing gastrointestinal symptoms that are often ignored in research on physical comorbidities of schizophrenia. The aim was to assess dyspepsia and constipation in a sample of outpatients with schizophrenia spectrum psychoses. A general practitioner performed a thorough physical health check for 275 outpatients and diagnosed constipation and dyspepsia. This study assessed the possible contribution of several sociodemographic, lifestyle, and clinical variables to constipation and dyspepsia using logistic regression analysis. This study also assessed whether these symptoms were associated with abnormal laboratory findings. The prevalence of constipation was 31.3%, and of dyspepsia 23.6%. Paracetamol (OR =3.07, 95% CI =1.34-7.02) and clozapine use (OR =5.48, 95% CI =2.75-10.90), older age (OR =1.04, 95% CI =1.01-1.06), and living in sheltered housing (OR =2.49, 95% CI =1.16-5.33) were risk factors for constipation. For dyspepsia the risk factors were female sex (OR =2.10, 95% CI =1.15-3.83), non-steroidal anti-inflammatory drugs (OR =2.47, 95% CI =1.13-5.39), and diabetes medication (OR =2.42, 95% CI =1.12-5.25). Patients with dyspepsia had lower haemoglobin and haematocrit and higher glucose values than those without dyspepsia. Patients with constipation had lower thrombocyte values than patients without constipation. However, these findings were explained by factors pre-disposing to constipation and dyspepsia. Clozapine use markedly increases the risk of constipation and may lead to life-threatening complications. In addition, analgesics and diabetes medication were related to gastrointestinal symptoms. These medications and their association to gastrointestinal symptoms should be kept in mind when treating patients with schizophrenia.

Clozapine-induced dysphagia with secondary substantial weight loss

Dysphagia is listed as a 'rare' side effect following clozapine treatment. In this case report, we describe how significant clozapine-induced dysphagia has led to significant reduction of nutritional intake with subsequent substantial weight loss. An 18-year-old single man with an established diagnosis of treatment-resistant paranoid schizophrenia recovered well on a therapeutic dose of clozapine. However, he was noted to lose weight significantly (up to 20% of his original weight) as the dose was uptitrated. This was brought about by development of dysphagia, likely to be due to clozapine. Addition of nutritional supplementary liquids and initiation of a modified behavioural dietary/swallowing programme, while repeatedly mastering the Mendelsohn manoeuvre technique, alleviated the swallowing difficulties and restored his weight.

Rare and very rare adverse effects of clozapine

Clozapine (CLZ) is the drug of choice for the treatment of resistant schizophrenia; however, its suitable use is limited by the complex adverse effects' profile. The best-described adverse effects in the literature are represented by agranulocytosis, myocarditis, sedation, weight gain, hypotension, and drooling; nevertheless, there are other known adverse effects that psychiatrists should readily recognize and manage. This review covers the "rare" and "very rare" known adverse effects of CLZ, which have been accurately described in literature. An extensive search on the basis of predefined criteria was made using CLZ and its combination with adverse effects as keywords in electronic databases. Data show the association between the use of CLZ and uncommon adverse effects, including ischemic colitis, paralytic ileus, hematemesis, gastroesophageal reflux disease, priapism, urinary incontinence, pityriasis rosea, intertriginous erythema, pulmonary thromboembolism, pseudo-pheochromocytoma, periorbital edema, and parotitis, which are influenced by other variables including age, early diagnosis, and previous/current pharmacological therapies. Some of these adverse effects, although unpredictable, are often manageable if promptly recognized and treated. Others are serious and potentially life-threatening. However, an adequate knowledge of the drug, clinical vigilance, and rapid intervention can drastically reduce the morbidity and mortality related to CLZ treatment.

Clozapine use pattern in persons with and without treatment for Parkinson's disease in real-world conditions: a naturalistic study in a community-based sample

OBJECTIVE

To explore the pattern of clozapine use in persons with severe mental illness and in persons with Parkinson's disease and the characteristics associated with early discontinuation in naturalistic conditions.

METHOD

A historical fixed cohort study of persons newly treated with clozapine was performed on a representative community-based sample of persons affiliated to the French health insurance system (n = 611,393). Treatment for Parkinson's disease was used as a proxy for this condition and lack of such treatment as a proxy for severe mental illness (SMI).

RESULTS

The prevalences of antipsychotic and clozapine use were 4.4% and <0.1% respectively. Of the 237 persons with a new outpatient prescription of clozapine, 25% were prescribed an antiparkinsonian treatment. In persons with SMI, the median duration of the index episode of clozapine treatment was 4.9 months (Interquartile range 1.0-20.5). Longer duration was independently associated with coprescription of anxiolytics or antidepressant. Few new additions of antipsychotics were observed during the clozapine episode.

CONCLUSION

Efforts have to be made to optimize clozapine treatment in real-world conditions. Considering the high frequency of persons with Parkinson's disease among clozapine users, further studies have to be performed in this population.

Life-threatening haematemesis associated with clozapine: a case report and literature review

Clozapine is regarded as a second-line and in some cases last-line antipsychotic known for its common life-threatening side effects, such as agranulocytosis, constipation and cardiomyopathies, but rarely haematemesis. We report a case of severe haemetemesis in a chronic schizophrenic patient managed with clozapine. The patient was a 46-year-old male being managed for chronic schizophrenia with treatment resistance who developed sudden severe haematemesis following commencement of clozapine for 6 weeks. The patient had 1.1 l of blood transfusion. The relevant literature is reviewed. Clozapine can be associated with a life-threatening haematemesis. Psychiatrists and other medical specialists need to be alert to the fatality of clozapine-induced haematemesis in the treatment of psychiatric disorders.