Prolongation of clozapine-induced neutropenia with olanzapine

Alert prescribing of clozapine: a comparison of five drug-drug interaction sources

Introduction

Clozapine, an antipsychotic used in the treatment of schizophrenia, is known for its serious side effects. In order to promote patient safety, drug-drug interaction (DDI) databases can be consulted by clinicians. In this study, the degree of consensus between five sources on DDIs with clozapine is determined.

Methods

The summary of product characteristics of clozapine, Delphicare interaction database, Stockley's interaction checker, the Lexicomp interaction database, and the interaction database of Clinical Pharmacology are included. By comparing the original categories assigned to interactions with clozapine by the included DDI sources, a degree of consensus between sources is determined. Furthermore, based on the combined information, an evaluation on the severity of each potential interaction is made.

Results

One hundred eighty-three potential DDIs with clozapine are retrieved from the five included sources. A consensus between sources is found in 47.5% (n = 87) of DDIs.

Conclusion

This study shows major discrepancies between five different sources on DDIs with clozapine. The potential impact of the use of one specific database on patient safety and prescribing behavior could prove to be problematic.

Severe complications of tramadol overdose in Iran

OBJECTIVES

Severe complications of tramadol overdose have been reported; however, few large-scale studies have investigated this issue. Therefore, this study aimed to explore the presentation and complications of tramadol overdose in patients admitted to an intoxication referral center in northwestern Iran.

METHODS

Patients with tramadol overdose admitted to Sina Teaching Hospital in Tabriz, Iran during 2013-2017 were included. For each patient, the following data were collected: demographics, previous drug or medication overdose, whether the patient was in the process of quitting drug use, ingested dose of tramadol and co-ingestants, Glasgow Coma Scale (GCS) score, clinical symptoms at the time of admission, and admission characteristics. Serotonin toxicity was diagnosed in patients who fit the Hunter criteria. Multiple logistic regression was performed to identify variables associated with the incidence of severe complications of tramadol overdose.

RESULTS

In total, 512 cases of tramadol overdose were evaluated, of which 359 patients were included, with a median age of 41 years (range, 16-69) and a median tramadol dose of 1,500 mg (range, 500-4,000). The most frequent complications associated with tramadol overdose were hypertension (38.4%), tachycardia (24.8%), and seizure (14.5%). No serotonin toxicity was detected in patients. Having a GCS score <15, having taken a tramadol dose of >1,000 mg, being in the process of quitting drug use, being 30-49 years old, and male sex were significantly related to the incidence of severe complications of tramadol overdose.

CONCLUSIONS

Although seizure was prevalent among Iranian patients with tramadol poisoning, serotonin toxicity and cardiogenic shock were rare findings.

Management of severe arterial hypertension associated with serotonin syndrome: a case report analysis based on systematic review techniques

Serotonin syndrome is thought to arise from serotonin excess. In many cases, symptoms are mild and self-limiting. But serotonin syndrome can become life threatening, when neuromuscular hyperexcitability spins out of control. Uncontainable neuromuscular hyperexcitability may lead to cardiovascular complications, linked to extreme changes in blood pressure. Currently, there is little guidance on how to control blood pressure in hyperserotonergic states. We report a case with treatment-resistant arterial hypertension, followed by a clinical review (using systematic review principles and techniques) of the available evidence from case reports published between 2004 and 2016 to identify measures to control arterial hypertension associated with serotonin syndrome. We conclude that classic antihypertensives may not be effective for the treatment of severe hypertension associated with serotonin syndrome. Benzodiazepines may lower blood pressure. Patients with severe hypertension not responding to benzodiazepines may benefit from cyproheptadine, propofol or both. In severe cases, higher cyproheptadine doses than currently recommended may be necessary.

Tramadol-Induced Mood Elevation in a Patient with No Previous Psychiatric History

Tramadol is a powerful analgesic medication with antidepressant effects like venlafaxine. Hypomanic features were reported in patients with psychiatric history of mood disturbance when tramadol was prescribed for them. However, it is extremely rare to notice such mood-elevating effect in patients who have no previous psychiatric history. We report on the observation of a distressing mood-elevating effect for tramadol in a patient with no previous psychiatric history. We present the case of a 26-year-old female patient who developed accelerated flow of speech, overactivity, and difficulty in sleeping following intake of tramadol 50 mg dose. These symptoms resolved four hours later and recurred as she retook tramadol. The patient has no history of mood disorder or any other psychiatric comorbidity. Clinicians should exercise caution when prescribing tramadol.

Tramadol overdose causes seizures and respiratory depression but serotonin toxicity appears unlikely

CONTEXT

Tramadol is a commonly used centrally acting analgesic associated with seizures and suspected to cause serotonin toxicity in overdose.

OBJECTIVE

This study sought to investigate the effects of tramadol overdose, and included evaluation for serotonin toxicity based on the Hunter Serotonin Toxicity Criteria where the seven clinical features of spontaneous clonus, inducible clonus, ocular clonus, agitation, diaphoresis, tremor and hyperreflexia are examined for in all patients taking serotonergic medications; seizures and central nervous system depression.

MATERIALS AND METHODS

This was an observational cases series based on a retrospective review of tramadol overdoses (> 400 mg) admitted to a tertiary toxicology unit from November 2000 to June 2013. Demographic details, information on ingestion (dose and co-ingestants), clinical effects, complications (seizures, serotonin toxicity and cardiovascular effects) and intensive care unit (ICU) admission were extracted from a clinical database.

RESULTS

There were 71 cases of tramadol overdose (median age: 41 years, range: 17-69 years; and median ingested dose: 1000 mg, interquartile range [IQR]: 800-2000 mg). Seizures were dose related and occurred in 8 patients, one of them co-ingested a benzodiazepine compared with 16 patients without seizures. There were no cases of serotonin toxicity meeting the Hunter Serotonin Toxicity Criteria. Tachycardia occurred in 27 and mild hypertension occurred in 32. The Glasgow Coma Score was < 15 in 29 and < 9 in 5 patients; three co-ingested tricyclic antidepressants and two tramadol alone (3000 mg and 900 mg). Respiratory depression occurred in 13, median dose: 2500 (IQR: 1600-3000) mg which was significantly different (p = 0.003) to patients without respiratory depression, median dose: 1000 (IQR: 750-1475) mg. Eight patients were admitted to ICU, five due to co-ingestant toxicity and three for respiratory depression.

DISCUSSION

Tramadol overdose was associated with a significant risk of seizures and respiratory depression in more severe cases, both which appear to be related to the ingested dose. There were no cases of serotonin toxicity, while opioid-like effects and adrenergic effects were prominent.

CONCLUSION

Tramadol overdose is associated with seizures and respiratory depression, but is unlikely to cause serotonin toxicity.

The atypical antipsychotic clozapine selectively inhibits interleukin 8 (IL-8)-induced neutrophil chemotaxis

Clozapine is the most effective antipsychotic to date, but its benefits are counterbalanced by the risk of severe hematological effects. In this study, we analyzed whether clozapine inhibits polymorphonuclear (PMN) leukocyte chemotaxis. We found that clozapine, within the therapeutic concentration range, potently and selectively inhibits PMN chemotaxis induced by interleukin 8 (IL-8), a chemokine inducing neutrophil migration. The effect was not due to its action at dopamine, serotonin and muscarinic receptors, or to a direct antagonism to IL-8 receptors. Furthermore, clozapine did not inhibit PMN chemotaxis by its presumed toxic mechanism. In fact, after an overnight incubation in cell culture, the drug did not increase the physiological PMN apoptosis. An interference of clozapine with the autocrine release of leukotriene B4 (LTB4), a secondary chemoattractant secreted by neutrophils in response to the primary chemoattractant IL-8, was hypothesized. In agreement with this hypothesis, clozapine attenuated the IL-8-induced release of LTB4 in PMNs. A series of experiments with an antagonist of the LTB4 receptor, U75302, and an inhibitor of LTB4 synthesis, zileuton, provided support to this conjecture. Intriguingly MK-571, an inhibitor of the multi-drug resistance protein MRP4, playing a pivotal role in effluxing LTB4, completely blocked PMN chemotaxis induced by IL-8, but gave conflicting results when tested for its ability to reduce LTB4 release, increasing LTB4 efflux by itself but reducing the release when in combination with IL-8. The reduction of PMN chemotaxis due to clozapine could predispose patients to infections. Whether this effect is a prelude to clozapine agranulocytosis requires further investigation.

A case with neutropenia related with the use of various atypical antipsychotics

Herein, we report here a case of a 21-year-old patient with a conduct disorder, who had neutropenia associated with treatment with 4 different antipsychotics (olanzapine, quetiapine, risperidone, and aripiprazole) on a sequential basis. This case supports the hypothesis that patients who developed antipsychotic-induced neutropenia on one medication are more likely to develop neutropenia when taking other antipsychotics. Based on this finding, we may suggest that the number of white blood cell and neutrophil counts in patients with a history of antipsychotic-induced neutropenia needs to be carefully monitored during antipsychotic treatment.

Avoiding Serotonin Syndrome: The Nature of the Interaction Between Tramadol and Selective Serotonin Reuptake Inhibitors

Objective:

To investigate the nature of the interaction between selective serotonin reuptake inhibitors (SSRIs) and tramadol to mitigate or avoid serotonin syndrome.

Data Sources:

PubMed, Ovid MEDLINE, and International Pharmaceutical Abstracts from January 1990 to August 2012 were searched. Key words used were tramadol, antidepressive agents, antidepressants, drug interactions, selective serotonin uptake inhibitors, and serotonin syndrome.

Study Selection and Data Extraction:

Only English-language studies were included. No randomized controlled trials were identified. Review articles, case reports, and 1 case series that identified the scope of interaction between tramadol and SSRIs were evaluated. Review articles evaluating the role of pharmacogenetics in the use of tramadol, SSRIs, and serotonin syndrome were also reviewed.

Data Synthesis:

Published documentation describing the interaction between tramadol and SSRIs and its relevance to serotonin syndrome is limited to a few case reports and 1 case series. While both tramadol and SSRIs increase the amount of serotonin in the brain, the interaction is much more complicated. Tramadol is metabolized through CYP2D6 enzymes and all SSRIs are inhibitors of these enzymes. Inhibitors of CYP2D6 can increase the concentration of tramadol in the blood and thus increase its effects on serotonin in the brain, contributing to the development of serotonin syndrome. CYP2D6 poor metabolizers are at a greater risk of serotonin syndrome and an inadequate analgesic effect.

Conclusions:

Coadministration of tramadol and SSRIs has caused serotonin syndrome. An attempt should be made to identify individuals who are poor metabolizers of CYP2D6 and avoid this combination in those patients. When SSRIs and tramadol must be used in combination, it is critical that patients be aware of the signs and symptoms of serotonin syndrome, should they occur.

Does switching to another antipsychotic in patients with clozapine-associated granulocytopenia solve the problem? Case series of 18 patients

Clozapine is a well-known drug that is used in treatment-resistant schizophrenia, but granulocytopenia, which may lead to a potentially fatal condition such as agranulocytosis, limit its use. The question about which antipsychotic should be used after a diagnosis of clozapine-associated granulocytopenia is difficult to answer, because antipsychotics other than clozapine may also have hematologic toxicity, or they may prolong clozapine-associated granulocytopenia. In this study, we aimed to find out the incidence of clozapine-associated granulocytopenia in our treatment sample and discuss suitable antipsychotic drug options in terms of hematologic toxicity, for management of clozapine-associated granulocytopenia.

SUBJECTS

One thousand five hundred twenty-four schizophrenia patients, treated with clozapine, were included in the study.

METHODS

Patients' white blood cell counts were monitored closely. Should granulocytopenia related to clozapine be diagnosed, clozapine was stopped immediately, and a new antipsychotic that the patient did not have a history of use was begun, according to the clinical profile of the patient. Persistent low white blood cell count after the 10th day of cessation of clozapine was accepted as prolongation effect.

RESULTS

Of the 1524 schizophrenia patients, 18 were diagnosed to have granulocytopenia, which means that 1.18% of the clozapine users developed granulocytopenia related to clozapine. Six of the patients were treated with olanzapine, 5 patients were treated with quetiapine, 1 patient was treated with risperidone, and 6 patients were treated with amisulpride after clozapine is stopped. None of the patients treated with risperidone or amisulpride showed prolonged low white blood cell count. Two of the patients treated with olanzapine (33.3%) and 2 of the patients treated with quetiapine (40.0%) showed prolonged leukopenia.

DISCUSSION

It is noteworthy that 33.3% of the patients treated with olanzapine and 40.0% of the patients treated with quetiapine showed prolonged leukopenia. This finding is also consistent with the literature that declares higher numbers of cases about prolongation of clozapine-associated granulocytopenia for olanzapine and quetiapine than risperidone and amisulpride. After switching to another antipsychotic drug, close monitoring of white blood cell count on a daily basis for the first 2 weeks should be continued until white blood cell counts are stabilized. Quetiapine and olanzapine especially need attention after clozapine-associated granulocytopenia. Further studies with larger series and longer follow-up should be carried out.

Haematological toxicity of clozapine and some other drugs used in psychiatry

OBJECTIVE

To review recent work on the haematological toxicity of clozapine and some other drugs used in psychiatry concerning especially (i) the mechanism of antipsychotic-induced neutropenia/agranulocytosis, (ii) criteria for clozapine prescribing in benign ethnic neutropenia, (iii) options in the event of worrying falls in white cell count (WCC), including measures to boost WCC with or without continued clozapine administration, (iv) criteria for clozapine rechallenge in the event that treatment was suspended because of a fall in WCC and (v) safety concerns regarding clozapine in children/adolescents.

CONCLUSIONS

There remain several difficult areas, including the criteria for clozapine rechallenge. Experience has emphasised (i) the role of appropriate timing of WCC sample collection to ensure that clozapine is not withdrawn unnecessarily and (ii) the success of agents such as filgrastim in promoting rapid production of granulocytes if the situation so demands. On the other hand, the use of lithium to promote a leucocytosis has taken hold without a clear risk: benefit analysis. Be this as it may, should patients decide that they no longer wish to undergo WCC monitoring after 12 months on clozapine, cessation of monitoring is probably preferable to stopping the drug since overall mortality is decreased in patients treated with clozapine.

Paroxetine

BACKGROUND

Paroxetine is a widely used antidepressant that has received attention regarding suicide risk in younger patients.

OBJECTIVE

The purpose of this paper is to review the pharmacology, efficacy and safety of paroxetine in the affective disorders.

METHODS

The authors performed a PubMed search for all literature in English crossing the words 'paroxetine' and 'Paxil' against the words 'serotonin transporter,' 'clinical trials,' 'depression' and 'SSRI'. A search for paroxetine-related information at the FDA website and under the clinical trial register of the GSK website were also performed.

RESULTS/CONCLUSION

Paroxetine is a serotonin re-uptake inhibitor with good selectivity and no significant active metabolites. Paroxetine is approved (ages >or= 18 years) for the treatment of major depressive disorder, panic disorder, obsessive-compulsive disorder, social anxiety disorder (social phobia), post-traumatic stress disorder, and generalized anxiety disorders. Drug - drug interactions involving the CYP enzyme system have been documented, as well as concern for increased suicidality risk in younger adults and recent FDA alerts regarding teratogenicity, serotonin syndrome and persistent pulmonary hypertension.