A case report of clozapine-induced gastric outlet obstruction

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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Reintroduction of Clozapine After Perforation of the Large Intestine—A Case Report and Review of the Literature

OBJECTIVE

To report on a patient who was successfully rechallenged with clozapine after perforation of the large intestine and pulmonary embolism postoperatively, and provide a literature review on clozapine rechallenge.

CASE SUMMARY

A 46-year-old Japanese man with treatment-resistant schizophrenia developed constipation and slight abdominal discomfort while taking clozapine 275 mg/day. He developed appendicitis, leading to perforation of the large intestine. During the postsurgery period, a partial embolism of the pulmonary artery was revealed. The patient's constipation was relieved when clozapine was discontinued, but other antipsychotics failed to control his delusions well. After thorough discussion, it was decided to rechallenge with clozapine. The low dose of clozapine 200 mg/day was tolerable for his delusion, and his constipation was managed with laxatives and exercises until 8 months after the accident.

DISCUSSION

Clozapine is a gold standard medication in treatment-resistant schizophrenia but is associated with various adverse effects, some of which are life-threatening. Reintroduction of clozapine after severe adverse drug effects when other medications are not effective almost always poses a clinical dilemma for mental health professionals. A PubMed search (to January 25, 2013) using the key words clozapine and rechallenge found 50 articles. There were only sporadic positive case reports regarding the rechallenge after clozapine-related serious gastrointestinal problems.

CONCLUSIONS

From the currently available evidence, most psychiatrists appear to avoid reintroduction of clozapine. However, the evidence is too weak to draw a definitive conclusion about reintroduction of this drug. Reintroduction of clozapine after initial adverse effects in patients with treatment-resistant schizophrenia may warrant case-by-case judgment, but needs to be further investigated.

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.

Clozapine-induced microscopic colitis: a case report and review of the literature

Both diarrhea and colitis associated with clozapine have been reported. In this article, the authors present a case of clozapine-induced microscopic colitis (MC)-the first reported in the literature. The definitive diagnosis was suggested on colon biopsy, which showed an intraepithelial lymphocytosis (with >20 lymphocytes for every 100 epithelial cells) more striking in the surface epithelium than in the crypts. In addition, there were a mixed inflammatory infiltrate in the lamina propria (with lymphocytes predominating over eosinophils and neutrophils), an architecturally preserved colonic mucosa (particularly in the crypts), and a subepithelial collagen band normally thickened (<10 microm). Clozapine was thought to be the culprit and discontinued. After some days, the patient gradually improved. Diarrhea and spiking fever disappeared within 72 hours. Multiple colon biopsies taken after 7 days from the discontinuation of the clozapine revealed no abnormal histological findings. It is important to clarify the issue of clozapine-induced MC because MC may require the use of expensive or potentially toxic treatments and can occasionally be life-threatening (eg, hypokalemia). Thus, any case of MC that can be cured by withdrawal of the clozapine must be investigated and identified.

Paralytic ileus associated with combined atypical antipsychotic therapy

First- and second-generation antipsychotics commonly cause mild and sometimes severe gastrointestinal motility depression. We discuss a case of a patient who developed paralytic ileus during his treatment with a combination of second-generation antipsychotics. The patient did not receive other medication that could cause depression of intestinal motility than the above-mentioned combination of antipsychotics and no other etiology could be found for the ileus. Furthermore we discuss the theoretical background of antipsychotics induced gastrointestinal motility depression and we provide the literature review of case reports of this topic.