Novel antipsychotics and the neuroleptic malignant syndrome: a review and critique

Neuroleptic malignant syndrome due to three atypical antipsychotics in a child

Neuroleptic Malignant Syndrome (NMS) is a rare, potentially fatal and idiosyncratic drug reaction. It is characterized by a sudden loss of body temperature control, renal and respiratory failure, muscle rigidity, loss of consciousness and impairment of autonomic nervous system. Although NMS was previously associated with the use of classical high-potency neuroleptics, cases have started to emerge with atypical neuroleptics. This article discusses the first case of NMS in a child, induced by the use of risperidone, olanzapine and quetiapine.

Possible malignant neuroleptic syndrome that associated with hypothyroidism

A 54-year-old woman with schizophrenia presented to hospital with unconsciousness, fever and marked muscle rigidity. She had been given fluphenazine decanoete 20 mg intramuscularly 15 days before the admission and she had continued taking haloperidol 20 mg daily and oral biperiden 2-4 mg. She was extremely rigid and unresponsive. On laboratory investigations revealed: serum sodium 120 mEq/l, creatinine phosphokinase 12,980 IU/l (normal up to 170), lactate dehydrogenase 1544 IU/l (150-500), free trioidothyronine < 1.00 pg/ml (1.5-4.5), free throxyine 0.76 ng/dl (0.8-1.9), thyroid stimulating hormone 1.14 microU/ml (0.4-4), cortisol (at 8.00 a.m.) 9 microg/dl (5-25). Antipsychotic drugs were withdrawn after admission. A diagnosis of secondary adrenal insufficiency and secondary hypothyroidism was made. Hormonal substitution with hydrocortisone and levothyroxine and correction of hyponatremia with intravenous hypertonic saline solution resulted in rapid improvement of symptoms and signs. It seems that the symptoms and signs of hypothyroidism and hyponatremia were attributed to acute psychosis in this patient. As a conclusion failure to recognize the endocrinopathy may not only produce recovery difficulties but also psychiatric and endocrine repercussions if psychotropic medications are given in such masked cases.

Severe tachycardia following low-dose clozapine treatment

OBJECTIVE

To report a case of severe and sustained tachycardia that developed asymptomatically on a low dose of clozapine (150 mg daily).

METHOD

Case report.

RESULTS

Serially monitored 24 h heart rate after the introduction of clozapine showed an increase in the 24 h mean from 87 to 126 bpm, a reduction of pulse variability and anomalies in sleep-wake regulation. Cessation of clozapine was followed by a rapid return to preclozapine activity. Application of the Naranjo Adverse Drug Reaction Probability Scale indicated a probable relationship between clozapine and the sustained tachycardia.

CONCLUSIONS

Severe and sustained tachycardia can develop asymptomatically with a relatively low dose of clozapine and a slow titration rate. The severity of the tachycardia may not be revealed in isolated pulse measurements and may escape clinical detection without closer monitoring of heart rate.

Neuroleptic malignant syndrome in an adolescent after brief exposure to olanzapine

A 17-year-old African-American male developed neuroleptic malignant syndrome (NMS) with hyperthermia, autonomic instability, increased muscle tone, rhabdomyolysis, and obtundation after a maximum of 2 days of treatment with olanzapine and 1 day of treatment with divalproex sodium. Intensive care unit (ICU)-level care was required. Paranoid psychosis with catatonia was present after recovery from the NMS. Because of his continued psychotic symptoms following resolution of the NMS, the alternate atypical antipsychotic, clozapine, was started under close observation. Reports of NMS resulting from atypical antipsychotic agents are generally uncommon, and much more so in the child and adolescent population. However, these agents are frequently prescribed in this population and require due caution.

Atypical neuroleptic malignant syndrome associated with risperidone treatment in two adolescents

Neuroleptic Malignant Syndrome (NMS) is a known, life threatening, side effect of classical antipsychotic drugs. We report two cases of 16 and 17 year old males, who suffered life-threatening "NMS-Like" syndromes in association with Risperidone treatment. Further controlled studies are needed.

Psychopharmacohazardology: major hazards of the new generation of psychotherapeutic drugs

Balancing the benefits and risks of prescribing psychotherapeutic drugs requires knowledge of the baseline risks of genetics, lifestyle and morbidity of untreated illness. Superimposed upon these risks are some rare but potentially dangerous, uncomfortable or irreversible hazards of the antipsychotics, mood stabilizers, antidepressants and tranquillizers. Knowledge of these hazards facilitates monitoring and prompt intervention at the earliest sign of problems.

Genetic predisposition to neuroleptic malignant syndrome : implications for antipsychotic therapy

The pathogenetic mechanism of neuroleptic malignant syndrome (NMS), a potentially lethal adverse effect of antipsychotics, is not well understood. In addition to acquired risk factors, clinical observations suggest a number of genetic factors predisposing patients to NMS. Recent findings in pharmacogenetics indicate that the genetic polymorphisms for drug-metabolizing enzymes, drug transporters, and possibly drug-targeting molecules, are associated with the interindividual differences in drug responses concerning both efficacy and adverse reactions. Genetic association studies have sought to identify polymorphisms influencing susceptibility to NMS, especially with respect to the dopamine D(2) receptor, serotonin receptor, and cytochrome p450 2D6. While a few candidate polymorphisms were associated with NMS, a large controlled study is needed to attain statistical power. On the other hand, NMS might include heterogeneous conditions with common characteristic symptoms but different causative mechanisms. Further analysis of individuals with identified genetic mutations or polymorphisms should advance our understanding of mechanisms underlying NMS.

Drug-induced hyperthermia and muscle rigidity: a practical approach

Body thermoregulation can be violently offset by drugs capable of altering the balance between heat production and dissipation. Such events may rapidly become fatal. The drugs that are involved in the eruption of such syndromes include inhalation anaesthetics, sympathomimetic agents, serotonin antagonists, antipsychotic agents and compounds that exhibit anticholinergic properties. The resultant hyperthermia is frequently accompanied by an intense skeletal muscle hypermetabolic reaction that leads to rapidly evolving rigidity, extensive rhabdomyolysis and hyperkalemia. The differential diagnosis should, however, rule out non-drug-induced causes, such as lethal catatonia, central nervous system infection or tetanus, strychnine poisoning, thyrotoxic storm and pheochromocytoma. Prompt life-saving procedures include aggressive body temperature reduction. Patients with a suspected drug (or non-drug) hypermetabolic reaction should be admitted into an intensive care area for close monitoring and system-oriented supportive treatment. We present six conditions, in decreasing order of gravity and potential lethality, in which hyperthermia plays an essential role, and suggest a clinical approach in such conditions.

Neuroleptic malignant syndrome in an adolescent receiving olanzapine-lithium combination therapy

A 16-year-old boy developed fever, generalized rigidity, leukocytosis, and increased serum transaminase and creatine kinase levels while receiving treatment with olanzapine and lithium. When both drugs were discontinued, his fever and rigidity subsided and biochemical irregularities spontaneously returned to normal, without any complications. Classic neuroleptic malignant syndrome (NMS) was diagnosed. Concomitant administration of lithium with olanzapine may place patients at risk for NMS. Clinicians need to be aware of this rare but potentially fatal side effect in patients of all ages, and especially in adolescents receiving both drugs.

Neuroleptic malignant syndrome induced by atypical antipsychotics

A review of the English literature confirms that neuroleptic malignant syndrome (NMS) occurs with both traditional and atypical antipsychotic medications. Published reports of NMS induced by the traditional antipsychotics have given the practitioner valuable information on the prevention and treatment of this adverse effect. Case reports have also been published concerning NMS and clozapine, risperidone, olanzapine and quetiapine. By evaluating the case reports of atypical antipsychotic-induced NMS, valuable information may be obtained concerning similarities or differences from that induced by the traditional antipsychotics. The case reports of NMS with atypical antipsychotics were evaluated for diagnosis, age/sex of patient, risk factors, antipsychotic doses and duration of use, symptoms of NMS, and clinical course.

Malignant McLeod myopathy

Mild myopathy is a common manifestation of the X-linked McLeod neuroacanthocytosis syndrome. We present a patient with McLeod syndrome and a primarily subclinical myopathy, who developed severe rhabdomyolysis with renal insufficiency after a prolonged period of excessive motor restlessness due to an agitated psychotic state and a single dose of clozapine. Other possible causes for rhabdomyolysis such as prolonged immobility, trauma, hyperthermia, generalized seizures, toxin exposure, or metabolic changes were excluded. Clinical course was favorable, with persistent slight elevation of serum creatine kinase levels caused by the underlying myopathy. Our findings suggest that McLeod myopathy is a predisposing factor for severe rhabdomyolysis. This possibly life-threatening condition should be added to the clinical spectrum of McLeod syndrome, and serum creatine kinase levels should be carefully monitored in patients with this syndrome, particularly if a hyperkinetic movement disorder is present or neuroleptic medication is used.

Olanzapine-associated neuroleptic malignant syndrome

Neuroleptic malignant syndrome (NMS) is an uncommon but serious idiosyncratic reaction associated with antipsychotic medication. The purpose of this study was to reveal and analyze the clinical characteristics of the reported cases of NMS in patients given the novel antipsychotic olanzapine. A MEDLINE search related to olanzapine-induced NMS cases reported in the international literature was conducted. All cases were critically reviewed and examined against three different sets of NMS diagnostic criteria (DSM-IV, Addonizio, Levenson). The authors identified 17 cases of possible NMS associated with olanzapine. Ten of the reported NMS cases were definitely NMS meeting all three sets of criteria and three cases were probable NMS meeting two sets of criteria. Most of the patients exhibited a full-blown NMS. There were four definite NMS cases associated with olanzapine monotherapy. Three of them had concurrent serious physical illnesses and one had a previous NMS episode. Olanzapine can cause NMS, mainly in susceptible or predisposed patients.

Atypical neuroleptic malignant syndrome associated with olanzapine

Neuroleptic malignant syndrome (NMS) is a potentially life-threatening adverse effect of antipsychotic agents. It generally is characterized by fever, altered mental status, rigidity, and autonomic dysfunction. A 53-year-old man developed NMS without rigidity while taking olanzapine. Such atypical cases may support either a spectrum concept of NMS or the theory that NMS secondary to atypical antipsychotics differs from that caused by conventional neuroleptics. More flexible diagnostic criteria than currently mandated by the the Diagnostic and Statistical Manual of Mental Disorders, Fourth Revision, may be warranted.

Neurotoxic syndrome associated with risperidone and fluvoxamine

OBJECTIVE

To report a case of a neurotoxic syndrome in a patient undergoing concomitant treatment with risperidone and fluvoxamine.

CASE REPORT

A 24-year-old African American woman hospitalized for psychosis was unresponsive to risperidone. Because of obsessive symptoms, low doses of fluvoxamine were added to her treatment regimen. Within 2 days, she developed confusion, diaphoresis, diarrhea, hyperreflexia, and myoclonus, which then progressed to rigidity, fever, and unresponsiveness, requiring endotracheal intubation. Symptoms resolved over 10 days with discontinuation of medication, hydration, and bromocriptine 5 mg 3 times daily. Ultimately, she was treated with olanzapine and fluvoxamine without adverse effects.

DISCUSSION

This represents the first reported case of a neurotoxic syndrome secondary to treatment with risperidone and fluvoxamine. Differential diagnosis between neuroleptic malignant syndrome (NMS) and serotonin syndrome (SS) could not be accurately determined because of the overlap of signs and symptoms of both syndromes. NMS and SS may represent different aspects of a more generalized neurotoxic syndrome. This could be an important consideration in formulating treatment for neurotoxic syndromes.

CONCLUSIONS

Clinicians should be aware of potentially serious adverse reactions that may occur during concomitant treatment with antipsychotics and selective serotonin-reuptake inhibitors.

Clinical risk factors for neuroleptic malignant syndrome

Pharmacological risk factors for neuroleptic malignant syndrome (NMS) are better defined than clinical risk factors. We examined the psychopathological status preceding the onset of NMS in 20 patients. We evaluated four key psychiatric symptoms (psychomotor agitation, catatonia, disorganization and confusion) and grouped them into definite clinical syndromes. Six patients presented with an acute and severe catatonic syndrome, with all the four key psychiatric symptoms. Twelve patients presented with an acute and severe disorganized psychotic episode, with two or three key psychiatric symptoms, but not catatonia. Our study suggests that a clinical syndrome of acute disorganization, in addition to acute catatonia, is a potential clinical risk factor for NMS. The two syndromes, which can occur in the context of different mental disorders, are related to each other as both implicate alteration in behavioural monitoring, and were, in our experience, unresponsive to neuroleptics. In conclusion, we hypothesize that the recognition of these two syndromes should reduce NMS occurrence. We recommend a judicious use of neuroleptics not only in patients with acute catatonia, but also in patients with acute disorganization.

Toxic interaction between risperidone and clozapine: a case report

Although atypical antipsychotics have generally a decreased risk of neurotoxicity, there are reports regarding various neurotoxic or idiosyncratic reactions including neuroleptic malignant syndrome (NMS). The authors present here the toxic interaction between risperidone (RIS) and clozapine (CLZ) in a first-episode schizophrenic patient. A 20-year-old man suffering from first-episode schizophrenia--catatonic subtype, developed a neurotoxic syndrome, which has been characterized as a mild form of NMS, after CLZ (100 mg/day) was added to a regimen of RIS (16 mg/day). The NMS symptomatology subsided only by drug discontinuation and supportive care. Later, CLZ monotherapy restarted without further complications. This case report shows that neurotoxic syndromes, even NMS, may occur during combination therapy with RIS and CLZ.

Treatment of neuroleptic malignant syndrome with subcutaneous apomorphine monotherapy

A 20-year-old psychiatric patient receiving haloperidol treatment developed acute-onset fever, rigidity, and mental changes. Subcutaneous apomorphine was given alone for treatment. The patient had rapid clinical improvement after the treatment. Serial blood examinations showed decline and subsequent normalization of the creatine phosphokinase levels.

Neuroleptic malignant syndrome during a change from haloperidol to risperidone

OBJECTIVE

To report a case of neuroleptic malignant syndrome (NMS) in a patient whose therapy was being switched from haloperidol to risperidone.

CASE REPORT

A 57-year-old African-American man, treated for schizophrenia with haloperidol for several years, developed NMS within 48 hours of the addition of low doses of risperidone and mirtazapine to his regimen. Symptoms, which included fever, generalized rigidity, and altered mental status, resolved after discontinuation of psychotropics, supportive management, and several weeks of treatment with bromocriptine and dantrolene. He was subsequently treated with olanzapine without adverse effects.

DISCUSSION

Several cases of NMS have been reported with risperidone, but none under these circumstances. NMS most likely occurred in this patient as a result of the additive dopamine 2 receptor blocking of haloperidol and risperidone. Sympathetic hyperactivity secondary to mirtazapine may also have been a contributing factor. If NMS may be induced by the simultaneous use of older, high-potency antipsychotics and newer, atypical antipsychotics such as risperidone, switching patients from older to newer antipsychotics may at times be difficult, since completely stopping one antipsychotic before starting the second may place patients at risk for psychotic relapse.

CONCLUSIONS

Clinicians should closely monitor patients receiving both haloperidol and risperidone or combinations of similar medications.

Clinical management of neuroleptic malignant syndrome

Neuroleptic malignant syndrome (NMS) continues to be an unpredictable and rare, but potentially fatal complication of antipsychotic medications. Presumptively linked to dopamine blockade, it nonetheless occurs in patients receiving newer atypical antipsychotics. The features of NMS, its pathophysiology, differential diagnosis, clinical course, risk factors, and morbidity and mortality are reviewed. Nonpharmacologic management centers on aggressive supportive care including vigilant nursing, physical therapy, cooling, rehydration, anticoagulation. Pharmacologic interventions include immediate discontinuation of antipsychotics, judicious use of anticholinergics, and adjunctive benzodiazepines. The utility of specific agents in actively treating NMS is reviewed. Bromocriptine and other dopaminergic drugs and dantrolene sodium have alternatively been considered without merit or efficacious. Guidelines for using these agents are presented. Electroconvulsive therapy, also somewhat controversial, is identified as a second line of treatment. Finally, management of the post-NMS patient is also reviewed.

Risperidone, neuroleptic malignant syndrome and probable dementia with Lewy bodies

1. Conflicting reports are available regarding the sensitivity of patients with Dementia with Lewy bodies (DLB) to risperidone. 2. The authors studied a rare familial case of probable DLB, who developed a documented episode of neuroleptic malignant syndrome (NMS) following the exposure to risperidone. Previously, the patient had had an episode of NMS on trifluoperazine. 3. The discontinuance of risperidone, in combination with a mild increase of dopaminergic therapy, led to a complete recovery in few days. 4. In patients with DLB, a continued vigilance for extrapyramidal side effects, including NMS, would be advisable during the use of risperidone.

Fatal status epilepticus associated with olanzapine therapy

OBJECTIVE

To report a case of fatal status epilepticus in a patient using olanzapine with no known underlying cause or predisposing factor for seizure.

CASE SUMMARY

A 41-year-old white woman developed witnessed seizures at home that progressed to status epilepticus. She subsequently died from secondary rhabdomyolysis and disseminated intravascular coagulation. She had been taking olanzapine for five months prior to the event. No other toxic, metabolic, or anatomic abnormalities were identified pre- or postmortem to explain the seizures. Her seizures were a probable adverse drug reaction based on the Naranjo scale.

DISCUSSION

This is the first case of fatal status epilepticus described that has been associated with the use of olanzapine. The pharmacodynamics of olanzapine are similar to those of clozapine, which has been described to induce seizures in 1-4% of patients. It is possible that this patient may have suffered seizures due to a similar effect. Alternate explanations include neuroleptic malignant syndrome and alcohol or benzodiazepine withdrawal seizures, although her clinical history does not suggest these etiologies.

CONCLUSIONS

Although olanzapine has infrequently been associated with seizures in premarketing studies, its potential to induce them exists. Postmarketing surveillance should continue to determine how significant this effect may be.

Clozapine-associated neuroleptic malignant syndrome: two new cases and a review of the literature

BACKGROUND

Clozapine has recently been found to be associated with neuroleptic malignant syndrome (NMS). Our objective is to determine if clozapine causes NMS, if the presentation of clozapine-induced NMS differs from that of traditional agents, and which set of diagnostic criteria will most readily allow diagnosis of NMS associated with clozapine.

METHODS

Two new cases of clozapine-associated NMS are presented, along with previously reported cases from the literature, identified by using a MEDLINE search (1966-August 1998). From all cases, concomitant medications and washout periods were examined (if available) to assess clozapine as the likely cause of NMS. Characteristics of clozapine and traditional antipsychotic-induced NMS were compared. Different diagnostic criteria for NMS were applied to the cases to determine which were more likely to diagnose the syndrome.

RESULTS

Clozapine was deemed a highly probable cause of NMS in 14 cases, a medium probability cause in five cases, and a low probability cause in eight cases. The most commonly reported clinical features were tachycardia, mental status changes, and diaphoresis. Fever, rigidity, and elevated creatine kinase were less prominent than in NMS associated with classical neuroleptics.

CONCLUSIONS

Clozapine appears to cause NMS, although the presentation may be different than that of traditional antipsychotics. Levenson's original and Addonizio's modified criteria were more likely to diagnose NMS than were other criteria. Clozapine-associated NMS may present with fewer clinical features. Limitations are the lack of detailed information provided by many of the case reports and the use of "modified" diagnostic criteria for retrospective diagnosis.