Olanzapine induced "typical" neuroleptic malignant syndrome

The Use of Physostigmine in the Diagnosis and Treatment of Anticholinergic Toxicity After Olanzapine Overdose: Literature Review and Case Report

BACKGROUND

Second-generation antipsychotic agents are commonly used by clinicians for the treatment of various psychiatric and medical conditions. Despite their presumed safety, an overdose with olanzapine may lead to the development of anticholinergic toxicity. The anticholinergic toxidrome is characterized by both central and peripheral physical findings. Central anticholinergic syndrome, a term used to describe the symptoms that arise from reduced cholinergic activity in the central nervous system, is characterized primarily by signs and symptoms consistent with hyperactive delirium. Signs of peripheral anticholinergia include mydriasis and blurred vision, tremors, ataxia, fever/hyperthermia, flushed and dry skin, dry oral mucosa, decreased bowel sounds, constipation, and urinary retention, among other symptoms. In extreme cases, central anticholinergic syndrome can be associated with seizures, coma, respiratory failure, and cardiovascular collapse.

OBJECTIVE

To provide scientific evidence regarding the efficacy and safety of physostigmine use in cases of anticholinergic toxicity.

METHODS

We conducted a comprehensive review of the published literature on the symptoms, diagnosis, and treatment of anticholinergic toxicity.

RESULTS

Currently the recommended treatment for olanzapine overdose, as is the case of most severe anticholinergic toxicity cases, involves supportive care, along with cardiac, neurological, and respiratory status monitoring. In addition, we detail the symptoms characteristic of anticholinergic toxicity, using the case of a patient experiencing central anticholinergic syndrome after an overdose with olanzapine.

CONCLUSION

Physostigmine, a tertiary acetylcholinesterase inhibitor, can be used to assist in the both the diagnosis and management of severe anticholinergic toxicity associated with an olanzapine overdose, which might be applicable to the antimuscarinic toxidrome associated with the ingestion of agents with significant anticholinergic activity.

Neuroleptic Malignant Syndrome: No Longer Exclusively a “Neuroleptic” Phenomenon

Objective:

To review the literature concerning the incidence of neuroleptic malignant syndrome (NMS) associated with the use of atypical antipsychotics.

Data Sources:

Cases were identified through a search of MEDLINE (1986–March 2004) using the terms neuroleptic malignant syndrome, antipsychotic, clozapine, risperidone, olanzapine, quetiapine, ziprasidone, and aripiprazole.

Study Selection and Data Extraction:

Case reports of possible NMS secondary to second-generation antipsychotics were selected for review. Reports meeting the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, criteria for NMS were considered. Case reports in which 1 of the 2 major diagnostic criteria was met were also included in the analysis. Furthermore, at least one minor criterion was met. Case reports in which patients received traditional antipsychotics were excluded.

Data Synthesis:

NMS is a rare and sometimes fatal disease. Several theories exist as to how NMS develops, and an equally large amount of diagnostic criteria are available. However, the majority of available data are based on the first-generation neuroleptics and very few exist with regard to the second-generation antipsychotics.

Conclusions:

Although there are numerous case reports of NMS occurring secondary to the use of second-generation antipsychotics, the incidence has never been fully elucidated. While the reasons for this remain uncertain, not all cases of second-generation–induced NMS fulfill the diagnostic criteria established for traditional neuroleptics and therefore may not be reported as such.

Olanzapine-Induced Malignant Neuroleptic Syndrome

Neuroleptic malignant syndrome (NMS), caused by antipsychotic therapy, shows itself with mental status alteration, high fever, autonomic dysfunction, and muscle rigidity. It is a rare idiosyncratic reaction with mortality risk. The etiology is still unknown. NMS-related mortality and morbidity can be decreased by cessation of the used drug and aggressive treatment. Olanzapine is a thienobenzodiazepine, a member of atypical antipsychotic drugs; its structure and effects on neurotransmitters resemble clozapine. Here we report a case of bipolar disorder receiving olanzapine therapy for 10 years, who developed NMS without rigidity. We emphasized the importance of early hydration and hemodiafiltration therapy.

Neuroleptic malignant syndrome developing after acute overdose with olanzapine and chlorpromazine

Neuroleptic malignant syndrome (NMS) is a relatively uncommon side effect that may develop after a recent increase in the therapeutic dose of an antipsychotic medication or the addition of a new agent in therapeutic doses.

CASE REPORT

We report a case of NMS developing in a 36-year-old female patient 2 days following deliberate self-poisoning with 30 x 10-mg olanzapine tablets, 7 x 100-mg chlorpromazine tablets and an unknown amount of escitalopram. These were the patient's own medications. She had not been taking these for several weeks. The patient initially presented with sedation from her overdose which resolved over the next 24 hours. Following this, over the subsequent 24 hours, she became progressively confused, ataxic, hypertonic, ferbrile and tachycardic, with marked lead pipe rigidity of the limbs. Head CT, lumbar puncture and septic screen were all negative. She was treated with intravenous midazolam infusion, nasogastrically administered bromocriptine, external cooling and was mechanically ventilated. She gradually improved over a period of 10 days, with residual confusion lasting another week, and was discharged well with no deterioration from her premorbid neurologic state.

CONCLUSION

To our knowledge, although there are numerous cases reported with therapeutic use, NMS has not been reported to develop following acute olanzapine overdose. Clinicians should be aware that this may be an uncommon side effect of antipsychotic medication.

Association Between Selective Serotonin-Reuptake Inhibitors, Second-Generation Antipsychotics, and Neuroleptic Malignant Syndrome

Objective

To review the published reports of neuroleptic malignant syndrome (NMS) associated with the use of selective serotonin-reuptake inhibitors (SSRIs) and second-generation antipsychotics.

Data Source:

Information was selected from a MEDLINE search of English-language literature (1950–May 2008). Manual search of all published cases indexed in MEDLINE (English language only) of NMS associated with second-generation antipsychotics was also performed.

Study Selection And Data Extraction:

Pertinent information from all reports obtained was included, with specific emphasis on patient age, sex, second-generation antipsychotic involved, SSRI or other antidepressant involved, time of onset of NMS symptoms in relation to medication changes, treatment administered, and outcome of the reaction.

Data Synthesis:

NMS has been reported with every second-generation antipsychotic agent. It is unclear whether concomitant therapy with other agents may increase the risk of NMS development via pharmacodynamic or pharmacokinetic mechanisms or both, The suggested pharmacodynamic mechanism for increased risk of NMS with concomitant use of SSRIs is the effect of serotonin on dopamine release. Serotonin further inhibits dopamine release and thereby may worsen a hypodopaminergic state induced by antipsychotics. Pharmacokinetic factors may also play a role in some NMS cases involving an SSRI by increasing antipsychotic concentrations. An examination of case reports seems to indícale that at least in some casos, a temporal relationship exists with the addition of an SSRI to existing antipsychotic therapy.

Conclusions:

The use of SSRIs may be associated with an increased risk of NMS development in (hose receiving second-generation antipsychotics. Clinicians should closely monitor patients for the potential development of NMS.