Intravenous injection of levodopa is more effective than dantrolene as therapy for neuroleptic malignant syndrome

Common toxidromes in movement disorder neurology

BACKGROUND

Physicians can come across patients who are exposed to certain prescription drugs or toxins that can result in adverse effects and complications which have high rates of morbidity and mortality.

OBJECTIVE

To summarise the key clinical features and management of the common movement disorder toxidromes relevant to physicians (with an interest in neurology).

METHODS

We searched PUBMED from 1946 to 2016 for papers relating to movement toxidromes and their treatment. The findings from those studies were then summarised and are presented here.

RESULTS

The key features of 6 of the common movement disorder toxidromes and their treatment are tabulated and highlighted. The management of toxidromes with the highest mortality like neuroleptic malignant syndrome and serotonin syndrome are discussed in detail.

CONCLUSION

There are several toxidromes that have the potential to become a serious life-threatening emergency if there is a delay in recognition of key clinical features and instituting the appropriate treatment at the earliest is crucial.

The Human Experience with Intravenous Levodopa

Objective: To compile a comprehensive summary of published human experience with levodopa given intravenously, with a focus on information required by regulatory agencies.

Background: While safe intravenous (IV) use of levodopa has been documented for over 50 years, regulatory supervision for pharmaceuticals given by a route other than that approved by the U.S. Food and Drug Administration (FDA) has become increasingly cautious. If delivering a drug by an alternate route raises the risk of adverse events, an investigational new drug (IND) application is required, including a comprehensive review of toxicity data.

Methods: Over 200 articles referring to IV levodopa were examined for details of administration, pharmacokinetics, benefit, and side effects.

Results: We identified 142 original reports describing IVLD use in humans, beginning with psychiatric research in 1959–1960 before the development of peripheral decarboxylase inhibitors. At least 2760 subjects have received IV levodopa, and reported outcomes include parkinsonian signs, sleep variables, hormone levels, hemodynamics, CSF amino acid composition, regional cerebral blood flow, cognition, perception and complex behavior. Mean pharmacokinetic variables were summarized for 49 healthy subjects and 190 with Parkinson's disease. Side effects were those expected from clinical experience with oral levodopa and dopamine agonists. No articles reported deaths or induction of psychosis.

Conclusion: At least 2760 patients have received IV levodopa with a safety profile comparable to that seen with oral administration.

Diagnosis and treatment of drug-induced hyperthermia

PURPOSE

The etiology, pathophysiology, clinical presentation, and management of drug-induced hyperthermia (DIH) syndromes are reviewed.

SUMMARY

DIH syndromes are a rare and often overlooked cause of body temperature elevation and can be fatal if not recognized promptly and managed appropriately. There are five major DIH syndromes: (1) neuroleptic malignant syndrome, (2) serotonin syndrome, (3) anticholinergic poisoning, (4) sympathomimetic poisoning, and (5) malignant hyperthermia. The differential diagnosis of DIH syndromes can be challenging because symptoms are generally nonspecific, ranging from blood pressure changes and excessive sweating to altered mental status, muscle rigidity, convulsions, and metabolic acidosis. Evidence from the professional literature (per a MEDLINE search for articles published through November 2011) indicates that few currently available treatment options can reduce the duration of hyperthermia; therefore, prompt identification of the provoking agent based on the patient's medication history, the clinical presentation, and the timing of symptom onset is essential to determine the appropriate treatment and mitigate potentially life-threatening sequelae. For all DIH syndromes, appropriate management includes the immediate discontinuation of the suspected offending agent(s) and supportive care (external cooling, volume resuscitation as needed); in some cases, pharmacologic therapy (e.g., a benzodiazepine, bromocriptine, dantrolene) may be appropriate, with the selection of a specific agent primarily determined by the medication history and suspected DIH syndrome.

CONCLUSION

DIH is a hypermetabolic state caused by medications and other agents that alter neurotransmitter levels. The treatment of DIH syndromes includes supportive care and pharmacotherapy as appropriate.

Neuroleptic malignant syndrome and its controversies

PURPOSE

Neuroleptic malignant syndrome (NMS) is a rare and life threatening condition usually defined as a complication of treatment with antipsychotics characterized by severe rigidity, tremor, fever, altered mental status, autonomic dysfunction, and elevated serum creatine phosphokinase and white blood cell count. The literature on this topic is rather extensive, but many aspects related to the syndrome are thought to be controversial. The aim of this paper, written with the clinician in mind, is to summarize some of the most prominent controversies that may have importance in usual clinical practice.

METHODS

The literature was searched for reviews, reports on the series of cases, individual case reports of NMS, and other clinically and theoretically important information.

RESULTS

There are controversies associated with virtually all important aspects of NMS. At the moment, it is not clear if this drug reaction is idiosyncratic or not, what diagnostic criteria are the most appropriate for usual clinical practice, and it seems that the estimated incidence is not in accordance with the number of treated patients. There are rather different approaches to the pathophysiological mechanisms, differential diagnosis, and treatment.

CONCLUSIONS

Some of the controversies related to NMS have an influence on our understanding of the condition and may have importance in clinical practice. There is a need for further research that should elucidate these controversies.

Atypical antipsychotics and newer antidepressants

Atypical antipsychotics and newer antidepressants are commonly prescribed medications responsible for tens of thousands of adverse drug exposures each year. The emergency medicine physician should have a basic understanding of the pharmacology and toxicity of these agents. This knowledge is crucial to providing proper care and timely management of patients presenting with adverse drug effects from exposure to atypical antipsychotics and newer antidepressants.

Managing an effective treatment for neuroleptic malignant syndrome

INTRODUCTION

Neuroleptic malignant syndrome (NMS) is a rare, but sometimes fatal, adverse reaction to neuroleptics characterized principally by fever and rigor. The aim of this study was to prove the efficacy of different NMS treatment strategies, focusing on the efficacy of dantrolene.

METHODS

Altogether, 271 case reports were included. These cases were categorized into four treatment groups and compared to each other according to effectiveness of therapy within 24 hours, mortality, complete time of remission in days, effectiveness due to increase of dosage, relapse on the basis of decrease of dosage, and improvement of symptoms.

RESULTS

Between the four treatment groups, the complete time of remission was significantly different (analysis of variance, F = 4.02; degrees of freedom = 3; p = 0.008). In a logistic regression with adjustment for age, gender, and severity code, no significant predictor of the treatment for the complete time of remission (dichotomized by median) could be found. However, if the premedication was a monotherapy with neuroleptics, the complete time of remission was significantly shorter with dantrolene monotherapy (t = -2.97; p = 0.004).

CONCLUSION

The treatment of NMS with drugs that are combined with dantrolene is associated with a prolongation of clinical recovery. Furthermore, treatment of NMS with dantrolene as monotherapy seems to be associated with a higher overall mortality. Therefore, dantrolene does not seem to be the evidence-based treatment of choice in cases of NMS but might be useful if premedication consisted of a neuroleptic monotherapy.

Neuroleptic malignant syndrome and serotonin syndrome

This chapter is focused on drug-induced hyperthermia with special regard to use of antipsychotics and antidepressants for the treatment of schizophrenia and major depression, respectively. Neuroleptic malignant syndrome (NMS) develops during the use of neuroleptics, whereas serotonin syndrome is caused mainly by serotoninergic antidepressants. Although both syndromes show various symptoms, hyperthermia is the main clinical manifestation. In this review we describe the historical background, clinical manifestations, diagnosis, and differential diagnosis of these two syndromes based on our observations on the experimental and clinical data.

The evaluation and management of patients with neuroleptic malignant syndrome

NMS is a rare but fatal syndrome that needs to be considered in the perioperative period. Although many aspects remain unexplored and controversial, with greater awareness of the condition, new concepts are coming into light. Definitive treatment guidelines remain an important issue to be addressed. Efforts have been initiated in that direction and all cases can be reported on a toll-free hotline ( 1-888-667-8367) or online (www.nmsis.org).

Efficacy of methylprednisolone pulse therapy on neuroleptic malignant syndrome in Parkinson's disease

BACKGROUND

Neuroleptic malignant syndrome (NMS) is a dangerous complication in patients with Parkinson's disease (PD).

AIMS

To evaluate the efficacy of methylprednisolone pulse therapy compared to placebo in PD patients with NMS.

METHODS

In a double blind, placebo controlled study, 20 PD patients with NMS received steroid pulse therapy for three days, and 20 PD patients received placebo. Both groups received levodopa, bromocriptine, and dantrolene.

RESULTS

NMS in the steroid group healed within 10 days in 17 patients; median value of duration of illness of NMS in this group was 7 days (range 4-20). NMS in the placebo group healed within 10 days in five patients; in the remaining 15, it persisted for 12-27 days after the onset of NMS; median value of duration illness of NMS in this group was 18 days. Hyperthermia, rigidity, and consciousness improved within 10 days in many patients in the steroid group; these signs persisted more than 10 days in many patients in the placebo group.

CONCLUSIONS

Steroid pulse therapy is useful in NMS for reducing the illness duration and improving symptoms.

The neuroleptic malignant and serotonin syndromes

The neuroleptic malignant syndrome and the serotonin syndrome share many clinical features and may exist on a spectrum of the same disorder. The neuroleptic malignant syndrome, however, is an idiosyncratic drug reaction, whereas the serotonin syndrome is an effect of drug toxicity. Both syndromes present with varying degrees of mental status changes and autonomic instability. In general, patients with the neuroleptic malignant syndrome have higher fevers and pronounced extrapyramidal signs with muscle rigidity, whereas patients with the serotonin syndrome have lower fevers, more gastrointestinal dysfunction, and myoclonus. Treatment for both syndromes consists of removing the offending agent and providing intensive supportive care. Syndrome-specific therapies are controversial.

[Neuroleptic malignant syndrome: case report with recurrence associated with the use of olanzapine]

The neuroleptic malignant syndrome (NMS) consists in an idiosyncratic reaction to neuroleptic drugs, probably related to a blockage of dopamine receptors in basal ganglia. Research criteria for diagnosing NMS from DSM-IV require severe rigidity and fever accompanied by 2 of 10 minor features including diaphoresis, dysphagia, tremor, incontinence, altered mentation, mutism, tachycardia, elevated or labile blood pressure, leukocytosis and elevation of creatine phosphokinase. From a clinical point of view, the NMS may range a large spectrum of presentations. Haloperidol is the most frequent drug associated with this syndrome. We report the case of a 30 year-old man who developed NMS at two different occasions, the first related to haloperidol and chlorpromazine and the second related to olanzapine, to our knowledge without previous mention in the indexed literature.