Case report: rapidly fatal bowel ischaemia on clozapine treatment

Clozapine-induced gastrointestinal hypomotility: presenting features and outcomes, UK pharmacovigilance reports, 1992-2017

BACKGROUND

Clozapine-induced gastrointestinal hypomotility (CIGH) affects some 75% of patients treated with clozapine.

AIMS

To document the incidence of potentially harmful CIGH in the UK.

METHOD

We studied spontaneous UK pharmacovigilance reports recorded as clozapine-related gastrointestinal adverse drug reactions, 1992-2017.

RESULTS

There were 527 patients reported with potentially harmful CIGH; 33% (n = 172) died. Deaths averaged 1 per year 1992-1999, 5 per year 2000-2009 and 15 per year 2010-2017. Those who died were older (median 52 years v. 49 years) and had been prescribed clozapine for longer than those who recovered (median 11.3 years v. 4.8 years), but there was no difference in prescribed dose. Within the first 4 years of clozapine treatment, there were 169 reports of CIGH, of which 3% (n = 5) were fatal. At 10-14 years there were 63 reports of CIGH, of which 25% (n = 16) were fatal. Among the deaths, males were younger (median 51, range 22-89 v. median 57, range 24-89 years) with higher clozapine doses (median 450, range 100-900 v. median 300, range 12.5-800 mg/d) than females. In non-fatal CIGH, surgery was the most frequent outcome (n = 92). The procedures included appendectomy, ileostomy, total/partial colectomy, colostomy/stoma and proctosigmoidectomy. Clozapine dosage was reduced in 6 patients, stopped and restarted in 23, 'continued' in 6 and discontinued permanently in at least 76 patients.

CONCLUSIONS

The risk of serious morbidity/mortality from CIGH is substantial. The need to actively monitor bowel function and give laxatives to patients treated with clozapine is clear.

Clozapine-Induced Constipation: A Case Report and Review of Current Management Guidelines

Clozapine is a second-generation antipsychotic recommended after the failure of two or more antipsychotics for treatment-resistant schizophrenia. Clozapine proved to also decrease recurrent suicidal behaviors in schizophrenia spectrum disorders. Yet, physicians often use clozapine as a last resort despite its proven efficacy due to its side effect profile. A noted side effect of clozapine is agranulocytosis, which requires a weekly complete blood count with differentials. Clozapine's anticholinergic activity causes colonic hypomotility, leading to constipation, and only a few studies examined clozapine-induced constipation (CIC). Few of the reported complications of CIC include bowel obstruction or bowel perforation due to fecal impaction. Herein we document a case report of CIC and also conducted a review of published case reports examining the complexity and management of CIC. CIC is a critical condition if unresolved as it can lead to mortality. Future directions and guidelines should be developed for early diagnosis and treatment for CIC, which will provide reassurance and directions for both the physicians and patients.

Second-generation antipsychotics and constipation: A review of the literature

Antipsychotics are the cornerstone in the management of psychotic disorders and schizophrenia. They are effective agents but also have a wide range of side effects. In the recent literature constipation as possible side effect has received little attention. A review of the literature concerning constipation associated with antipsychotics was performed. Overall constipation is a rarely studied or reported side effect of antipsychotic medication. Nevertheless constipation is a common side effect. Antipsychotic agents differ in their liability to induce constipation. Constipation can be severe and can lead to serious consequences such as paralytic ileus, bowel occlusion and death. Active screening, monitoring and treatment are recommended. Further research on incidence, prevalence, underlying mechanisms and preventive measures is required.

Clozapine-induced stercoral colitis: a surgical perspective

We describe a case of a 46-year-old man with schizophrenia treated with clozapine who presented as an emergency with abdominal pain on the background of a 1 month history of constipation. The initial presenting symptoms were vague and a diagnosis was difficult to establish. Initial CT of the abdomen and pelvis demonstrated only minor abnormalities. He continued to deteriorate until a further CT scan revealed worsening stercoral colitis. He subsequently underwent an emergency total colectomy and ileostomy formation and had a complicated prolonged postoperative recovery. This case highlights the risks that clozapine can have on slowing bowel transit and the dangerous consequences that can occur if not identified early.

Clozapine: why wait to start a laxative?

Clozapine, the antipsychotic of choice for treatment-resistant schizophrenia, has a number of side-effects, some of which are potentially life-threatening. Historically viewed as a relatively minor side-effect, there is increasing awareness of the potentially severe sequalae of constipation secondary to clozapine-induced gastrointestinal hypomotility (CIGH). These include ileus, intestinal obstruction, bowel ischaemia, gastrointestinal necrosis, toxic megacolon and death. CIGH is significantly more common than clozapine-induced blood dyscrasias and has a higher mortality rate. Although strict criteria must be followed to assertively monitor, detect and treat blood dyscrasias in patients taking clozapine, no such framework exists for CIGH. We recommend that prescribing guidelines, regulatory agencies and information from manufacturers should more clearly highlight the risks identified in the literature. Furthermore, we recommend that, in people taking clozapine, constipation should be prevented by prophylactic treatment with laxatives rather than treated only when clinically identified.

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Clozapine discontinuation in early schizophrenia: a retrospective case note review of patients under an early intervention service

AIM

Research in patients with treatment-resistant schizophrenia has demonstrated that clozapine discontinuation is associated with poor outcomes. There is, however, a paucity of research investigating the impact of clozapine discontinuation specifically in younger patients with more recent onset schizophrenia. A case note review was therefore conducted to ascertain medium-term prognoses in patients with treatment-resistant schizophrenia under an early intervention service (EIS) following clozapine discontinuation.

METHODS

The case notes of 25 patients under the care of Birmingham EIS who discontinued clozapine were examined retrospectively. Reasons for discontinuation were recorded. Clinical outcomes including total duration of inpatient or home treatment admission, antipsychotic dose, number of alternative antipsychotics prescribed and adverse events were recorded for both the year before and the year after stopping clozapine. Statistical comparisons of pre- and post-discontinuation clinical outcomes determined whether discontinuation had negative effects.

RESULTS

There was no significant difference between the pre- and post-discontinuation clinical status following clozapine discontinuation. More than half (56%) of patients remained stable after stopping clozapine. Mean inpatient or home treatment stay rose from 29.7 to 62.6 days (p = 0.155), total antipsychotic dose from 50.1% of British National Formulary (BNF) limits to 60.5% (p = 0.627), number of alternative antipsychotics prescribed from 1.28 to 1.80 (p = 0.186), number of hospital/home treatment episodes from 0.20 to 0.44 (p = 0.083) and number of adverse events from 0 to 0.20 (p = 0.059). Non-compliance was the main reason for discontinuation (44%, n = 11).

CONCLUSIONS

This is the first clozapine discontinuation study specifically considering EIS patients. Discontinuation did not lead to significant effects on 1 year outcomes, though the study is underpowered. These findings may be used to inform future prospective cohort discontinuation studies.

Clozapine induced gastrointestinal hypomotility: A potentially life threatening adverse event. A review of the literature

OBJECTIVE

The haematological and cardiac complications of clozapine have been well documented. Recent evidence from pharmacovigilance databases suggests that gastrointestinal (GI) complications are the leading cause of clozapine related deaths. This review aims to describe clinical features along with preventative and treatment options.

METHOD

A review of MEDLINE via PubMed searching for all articles published up to February of 2016. Inclusion criteria were articles that provided clinical or epidemiological information relating to the diagnosis, outcome, management or pathophysiology of clozapine related gastrointestinal disorders in humans.

RESULTS

Three large case series were identified with 104 cases, 20 of these reported clinical details. A further 52 cases reports were included. Median age was 40, with 79% being male, mean daily clozapine dose was 453 mg. Mortality was 38% with survivors being younger (39 vs. 42), on lower daily doses (400 mg vs. 532 mg), more likely to be female (32% vs. 6%). Four patients were re-challenged with clozapine following CIGH, two suffered a recurrence.

CONCLUSION

Risk factors for CIGH appear to be older age, male gender, patients in the first four months of treatment, co-prescription of constipating agents, higher daily dose of clozapine, and previous CIGH. Risk factors for death were older age and male gender. Patients receiving clozapine should be counselled about the dangers of constipation and to report new GI symptoms. Once severe CIGH has occurred clozapine should be halted and reviewed with bowel symptoms managed promptly. Re-challenging with clozapine may present substantial risks due to the severity of CIGH and a paucity of evidence. From the available evidence a treatment strategy has been proposed. Further prospective data regarding CIGH are needed to allow a better assessment of the scale of the problem with the development and testing of treatment strategies.

A Guide to the Management of Clozapine-Related Tolerability and Safety Concerns

Clozapine is a highly effective antipsychotic medication, which provides a range of significant benefits for patients with schizophrenia, and is the standard of care for treatment-resistant schizophrenia as well as for reducing the risk of suicidal behaviors in schizophrenia and schizoaffective disorder. However, clozapine is widely underutilized, largely because prescribing clinicians lack experience in prescribing it and managing its adverse events (AEs). Clozapine is associated with 3 uncommon but immediately dangerous AEs, agranulocytosis, myocarditis/cardiomyopathy, and seizures, as well as AEs that may become dangerous if neglected, including weight gain, metabolic syndrome and constipation, and others that are annoying or distressing such as sedation, nighttime enuresis and hypersalivation. Because of the risk of agranulocytosis, clozapine formulations are available only through restricted distribution via a patient registry, with mandatory, systematized monitoring for absolute neutrophil count using a specific algorithm. We identified articles on managing clozapine-associated AEs by searching PubMed using appropriate keywords and search techniques for each topic. A review of the prevalence and clinical characteristics of clozapine-associated AEs shows that these risks can be managed efficiently and effectively. The absolute risks for both agranulocytosis and myocarditis/cardiomyopathy are low, diminish after the first 6 months, and are further reduced with appropriate monitoring. Weight gain/metabolic disorders and constipation, which develop more gradually, can be mitigated with regular monitoring and timely interventions. Sedation, hypersalivation, and enuresis are common but manageable with ameliorative measures and/or medications.

Unrecognized clozapine-related constipation leading to fatal intra-abdominal sepsis - a case report

Clozapine is the preferred antipsychotic used for the treatment of resistant schizophrenia with suicidal ideation. The drug is started at a low dose and gradually increased to a target dose of 300–450 mg/day. It is well known to cause agranulocytosis and neutropenia. Several cases of fatal sepsis have been reported in neutropenic patients and emphasis is placed on monitoring for agranulocytosis; however, clozapine also causes intestinal hypomotility and constipation, which if unrecognized can lead to intestinal obstruction, bowel necrosis, and intra-abdominal sepsis. Reduced behavioral pain reactivity in schizophrenics may alter the ability to express pain, potentially leading to a delay in the presentation for medical attention. We report a case of fatal intra-abdominal sepsis secondary to an unrecognized case of clozapine-related constipation.

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-associated pneumonia and respiratory arrest secondary to severe constipation

Clozapine is often the drug of choice within patients suffering from treatment-resistant paranoid schizophrenia. It has a complex side effects profile which includes potentially fatal agranulocytosis. Clozapine has also become increasingly associated with a range of other side effects including constipation and pneumonia. We report on a case of clozapine-induced severe constipation leading to a silent presentation of pneumonia with a subsequent respiratory arrest. To our knowledge, this is the first case report of pneumonia secondary to severe constipation occurring in the absence of respiratory aspiration of feculent vomitus. We suggest a new pathological mechanism by way of severe constipation leading to diaphragmatic dysfunction and subsequent clozapine-induced pneumonia. In addition, implications for clinical practice are outlined.

Rapid development of fatal bowel infarction within 1 week after clozapine treatment: a case report

Although there have been reported fatalities associated with clozapine-induced bowel infarction, in all of these cases, the patients had taken clozapine for months to years. We present here the case of a 47-year-old single man who died suddenly due to bowel infarction and sepsis 1 week after taking clozapine.

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.

Risk factors for ileus in patients with schizophrenia

Constipation is a known side effect of psychotropics that possess high affinity for muscarinic cholinergic receptors. In severe cases, constipation progresses to ileus and bowel ischemia, with multiple fatalities related to sepsis and perforation described in the literature, primarily among patients with schizophrenia. A historical prospective database study was performed using registry data from psychiatric and somatic hospitals, combined with the prescription database to examine associations between medications and ileus. Only cases with an ICD-10 diagnosis of schizophrenia (F20) and a concurrent diagnosis of ileus in the years 1996-2007 were included in the study. A total of 26,720 patients with schizophrenia were identified with 123 cases of ileus noted in the study period. Increasing age (OR: 1.03 CI: 1.01-1.04) and female sex (OR: 1.60 CI: 1.10-2.31) were associated with an increased risk of ileus. Treatment with clozapine (OR: 1.99 CI: 1.21-3.29), high-potency first-generation antipsychotics (OR: 1.81 CI: 1.01-3.23), tricyclic antidepressants (OR: 2.29 CI: 1.29-4.09), anticholinergics (OR: 1.48 CI: 1.00-2.19), and opioids (OR: 2.14 CI: 1.36-3.36) were associated with an increased risk of ileus. The onset of ileus occurred on average more than 3 years after the first prescription of the offending drug. Aripiprazole and amisulpride were not associated with ileus. Nine of the ileus cases (7.3%) had a fatal course. Treatment with clozapine (OR: 6.73 CI: 1.55-29.17) or anticholinergics (OR: 5.88 CI: 1.47-23.58) were associated with increased risk of fatal ileus. Patients receiving psychotropics associated with significant anticholinergic properties should undergo proper monitoring and interventions in order to minimize the burden of constipation and the risk of ileus.

Plasma clozapine, norclozapine, and the clozapine:norclozapine ratio in relation to prescribed dose and other factors: data from a therapeutic drug monitoring service, 1993-2007

Therapeutic drug monitoring of plasma clozapine and of its principal plasma metabolite N-desmethylclozapine (norclozapine) (predose or "trough" sample) can help in monitoring adherence, in dose adjustment, and in minimizing the risk of toxicity. To obtain data to assist in the interpretation of analytical results, the results from a clozapine therapeutic drug monitoring service, 1993-2007, have been audited. There were 104,127 samples from 26,796 patients [18,750 (70%) men aged at time of first sample (median, range) 34 (10-89) years, and 7763 (30%) female aged 38 (12-90) years]. Clozapine was not detected (plasma concentration <0.01 mg/L) in 1.5% of samples (prescribed clozapine dose up to 900 mg/d). Plasma clozapine was either below 0.35 mg/L or greater than 0.60 mg/L in 42.5% and 28.4% of samples, respectively; in 0.4% samples plasma clozapine was 2.0 mg/L or more. Although plasma clozapine was broadly related to prescribed dose, there was much variation: 1.2% of samples had plasma clozapine >1.0 mg/L at prescribed clozapine doses up to 150 mg/d (76.2% < 0.35 mg/L), whereas 23.3% of samples had plasma clozapine < 0.35 mg/L at doses of 850 mg/d and over (18.0% > 1.0 mg/L). The highest plasma clozapine and norclozapine concentrations encountered were 4.95 and 2.45 mg/L, respectively. Although the median plasma clozapine:norclozapine ratio was 1.25 at plasma clozapine concentrations < 0.35 mg/L, the median ratio was 2.08 at plasma clozapine concentrations > 1.0 mg/L. Data (median, 10th-90th percentile) for both clozapine and norclozapine by prescribed clozapine dose band are useful in assessing partial adherence. Analysis of the plasma clozapine:norclozapine ratio by clozapine concentration provides clear evidence that clozapine N-demethylation becomes saturated at higher plasma clozapine concentrations and adds urgency to the requirement for dose adjustment should smoking habit change. A clozapine:norclozapine ratio greater then 2 suggests either a nontrough sample, or that clozapine N-demethylation has become saturated.

Gastrointestinal hypomotility: an under-recognised life-threatening adverse effect of clozapine

AIM

To highlight some problems that may occur when investigating clozapine-associated deaths including (i) that death may be related to gastrointestinal hypomotility and (ii) that post-mortem blood clozapine and norclozapine concentrations may not reflect ante-mortem concentrations.

CASE REPORTS

A 41-year-old male died 40 min after admission to hospital as a result of aspiration complicating severe, clozapine-induced constipation. At post-mortem the small bowel was dilated and contained bloodstained mucus, particularly within the jejunum. The large bowel was considerably dilated and contained large quantities of foul-smelling, bloodstained fluid and a small amount of stool. Its lining was focally congested, but there was no other obvious abnormality. Analysis of serum obtained on admission revealed clozapine and norclozapine concentrations of 0.56 and 0.43 mg/L, respectively, whereas post-mortem femoral whole blood obtained <34 h after death showed clozapine and norclozapine concentrations of 3.73 and 1.75 mg/L, respectively. In 6 out of a further 12 clozapine-associated deaths investigated 2002-9 there were reports of gastrointestinal tract problems of varying severity.

CONCLUSIONS

Severe constipation or paralytic ileus in clozapine-treated patients may lead to intestinal necrosis and/or perforation, or pulmonary aspiration. In some such cases the immediate cause of death may be obvious, but in others only careful assessment of the clinical course of the terminal illness may reveal gastrointestinal hypomotility as a likely underlying cause of death.

Successful Clozapine Rechallenge Following Surgical Repair of a Bowel Obstruction

As a consequence of its significant anticholinergic properties, constipation is a commonly reported adverse event in patients treated with clozapine. This side effect is often self-limiting and can be managed with high-fiber diets, adequate hydration, and standard over-the-counter and prescription preparations. However, severe cases of constipation can become more serious and may lead to intestinal obstruction, intestinal perforation, fecal impaction, or paralytic ileus. In this particular case, we report on a 44-year-old woman who presented with a suspected clozapine-induced bowel obstruction. Following total abdominal colectomy with ileosigmoid anastomosis, the patient was rechallenged with clozapine and tolerated the titration to a therapeutic dose and maintenance therapy without further incident.

Clozapine-induced bowel infarction: a case report

Resistant schizophrenia is often treated with clozapine after other conventional atypical antipsychotics have failed or have resulted in intolerable side effects. Clozapine is generally reserved for secondary use due to its propensity to cause serious side effects, such as life-threatening agranulocytosis and the necessity for life-long blood monitoring. In this case report we present a 40-year-old female patient who suffered from chronic constipation and bowel infarctions after long-term use with clozapine. Although the use of this medication resulted in multiple abdominal surgeries with subtotal colonic resections, the patient's schizophrenic symptoms only responded to clozapine after several repeat failures with other medications; ultimately, she was continued on this medication.

Reasons for discontinuing clozapine: matched, case-control comparison with risperidone long-acting injection

BACKGROUND

Clozapine has a range of serious adverse effects that may give rise to an increased risk of death.

AIMS

To compare reasons for discontinuation of clozapine with reasons for discontinuation of risperidone long-acting injection in age-matched individuals treated in the same clinical environment.

METHOD

Comparison of patients receiving clozapine and an age-matched control group receiving risperidone injection.

RESULTS

We established outcome for 529 consecutive patients receiving clozapine and 250 receiving risperidone (161 discontinuers from each group were compared). Adverse effects (odds ratio OR=2.19, 95% CI 1.31-3.67) and death (OR=7.0, 95% CI 2.09-23.5) were more commonly observed as reasons for discontinuation of clozapine than of risperidone. Clozapine was less likely to be withdrawn because of ineffectiveness than was risperidone (OR=0.034, 95% CI 0.01-0.14). Standardised mortality ratio (SMR) was significantly raised for patients receiving clozapine (SMR=4.17, 95% CI 2.78-6.26). Pneumonia was the most common single cause of death.

CONCLUSIONS

Clozapine use in patients with severe mental illness was associated with a significantly increased risk of death compared with that for the general population. Causation could not be established. Adverse effects and death are common causes of clozapine discontinuation.

Life-threatening constipation associated with clozapine

OBJECTIVE

The aim of this paper was to describe the association of clozapine with life-threatening constipation.

METHOD

Case report.

RESULTS

A 53-year-old man presented to the emergency department with severe abdominal pain and bilious vomiting after being on clozapine for over a year for schizoaffective disorder. Surgery revealed severe faecal impaction in the large and small bowel. Clozapine was ceased. There were significant difficulties in the subsequent psychiatric management. Clozapine was gradually reintroduced with concurrent laxative administration, which resulted in another episode of severe constipation with faecal impaction.

CONCLUSIONS

Clozapine can be associated with potentially life-threatening constipation. Psychiatrists, especially consultation liaison psychiatrists, physicians, surgeons and radiologists, should be aware of the seriousness of clozapine-induced constipation and its potentially fatal complications.