Acute lithium intoxication and neuroleptic malignant syndrome

A Case of Neuroleptic Malignant Syndrome in the Context of Lithium Toxicity and Aripiprazole Use

OBJECTIVE

Neuroleptic malignant syndrome (NMS) is a rare life-threatening condition that providers should be cognizant of when prescribing dopamine-receptor antagonists. Atypical antipsychotic agents were initially considered to have a lower risk of inducing the development of NMS compared with conventional antipsychotic. Considerable evidence, however, has suggested that atypical antipsychotics are associated with NMS, including the partial dopamine agonist, aripiprazole. There is growing evidence that other psychotropics, including lithium, cause this condition. Here, the authors present a case of a patient who developed NMS from lithium and aripiprazole and provide a literature review of reported NMS cases with either psychotropic.

METHOD AND RESULTS

The authors report the case of 60-year-old male patient who developed NMS over a hospital course during which both aripiprazole and lithium were prescribed. In addition, a literature review was performed and a summary of cases of NMS induced by either lithium and/or aripiprazole is provided.

CONCLUSIONS

This case adds to the growing body of literature of aripiprazole and lithium-induced NMS. Only 2 other cases are reported where concomitant aripiprazole and lithium use lead to NMS. Interestingly, our patient did develop lithium toxicity during hospitalization, but the NMS diagnosis occurred after lithium toxicity resolved. This varies from the other 2 cases where NMS developed despite lithium levels always being therapeutic. Unfortunately, there are more questions than answers surrounding this rare complication involving these 2 psychotropics and clinical vigilance is warranted when using these psychotropics especially in cases where aripiprazole and lithium are used in combination.

Pharmacological Augmentation in Unipolar Depression: A Guide to the Guidelines

BACKGROUND

Pharmacological augmentation is a recommended strategy for patients with treatment-resistant depression. A range of guidelines provide advice on treatment selection, prescription, monitoring and discontinuation, but variation in the content and quality of guidelines may limit the provision of objective, evidence-based care. This is of importance given the side effect burden and poorer long-term outcomes associated with polypharmacy and treatment-resistant depression. This review provides a definitive overview of pharmacological augmentation recommendations by assessing the quality of guidelines for depression and comparing the recommendations made.

METHODS

A systematic literature search identified current treatment guidelines for depression published in English. Guidelines were quality assessed using the Appraisal of Guidelines for Research and Evaluation II tool. Data relating to the prescription of pharmacological augmenters were extracted from those developed with sufficient rigor, and the included recommendations compared.

RESULTS

Total of 1696 records were identified, 19 guidelines were assessed for quality, and 10 were included. Guidelines differed in their quality, the stage at which augmentation was recommended, the agents included, and the evidence base cited. Lithium and atypical antipsychotics were recommended by all 10, though the specific advice was not consistent. Of the 15 augmenters identified, no others were universally recommended.

CONCLUSIONS

This review provides a comprehensive overview of current pharmacological augmentation recommendations for major depression and will support clinicians in selecting appropriate treatment guidance. Although some variation can be accounted for by date of guideline publication, and limited evidence from clinical trials, there is a clear need for greater consistency across guidelines to ensure patients receive consistent evidence-based care.

Lamotrigine, quetiapine and aripiprazole-induced neuroleptic malignant syndrome in a patient with renal failure caused by lithium: a case report

BACKGROUND

Neuroleptic malignant syndrome (NMS) may be induced by atypical antipsychotic drugs (AAPDs) such as aripiprazole, olanzapine, risperidone and quetiapine, either as a single treatment or in combination with other drugs. A case of NMS following the administration of lamotrigine, aripiprazole and quetiapine in a patient with bipolar disorder, and with renal failure caused by toxic lithium levels has not been reported.

CASE PRESENTATION

A 51-year-old female patient with a 27-year history of bipolar disorder, being treated with lithium, fluoxetine, olanzapine, gabapentine, perazine and biperiden, was admitted to the hospital due to depressed mood and delusions. A urinary tract infection was diagnosed and antibiotic therapy was initiated. After 5 days of treatment her physical state deteriorated and she developed a fever of 38.4 °C. Her laboratory results revealed a toxic level of lithium (2.34 mmol/l). Acute renal failure was diagnosed and the lithium was withdrawn. After stabilization of her condition, and despite her antipsychotic treatment, further intensification of delusions and depressed mood were observed. All drugs being taken by the patient were withdrawn and lamotrigine and aripiprazole were initiated. Due to the insufficient effectiveness of aripiprazole treatment and because of problems with sleep, quetiapine was added, however further treatment with this drug combination and an increase of quetiapine to 400 mg/d eventually caused NMS. Amantadine, lorazepam and bromocriptine were therefore initiated and the patient's condition improved.

CONCLUSION

This case report indicates that concurrent use of multiple antipsychotic drugs in combination with mood stabilizers in patients with organic disorders confers an increased risk of NMS development.

Toxicologic Emergencies in Patients with Mental Illness: When Medications Are No Longer Your Friends

Patients with psychiatric disorders are at risk for toxicologic emergencies. Psychotropic medications have numerous effects on the neurologic, cardiac, and other organ systems and interact with other medications, potentially leading to further side effects. It is important to become familiar with accepted psychiatric practice guidelines, common toxidromes, medical sequelae associated with prescribed medications, and the specific workup and treatment of overdoses of frequently prescribed psychotropics.

Ziprasidone- and Lithium-Induced Neuroleptic Malignant Syndrome

Objective:

To report a case of ziprasidone- and lithium-induced neuroleptic malignant syndrome (NMS).

Case Summary:

A 47-year-old white male with a history of schizoaffective disorder was admitted to the hospital due to an exacerbation of severe mania. He had been taking lithium 450 mg twice daily and divalproex sodium 750 mg/day. On hospital day 2, ziprasidone 80 mg twice daily was added, and as-needed doses of intramuscular ziprasidone 20 mg and lorazepam 2 mg were used for agitation. On day 6, the patient developed hyperthermia (39.4 °C), elevated creatine kinase 26 000 units/L and white blood cell (WBC) count (20.7 × 103/μL), myoglobinuria, hypotension (68/40 mm Hg), altered mental status, and tachypnea (28 breaths/min). This case is notable for the absence of muscle rigidity, which presents in greater than 90% of patients with NMS taking traditional antipsychotics.

Discussion:

This case of ziprasidone- and lithium-induced NMS is of probable cause, as determined by the Naranjo probability scale. The patient presented with symptoms consistent with NMS 4 days after initiation of ziprasidone and lithium. The majority of NMS cases present with the core features of hyperthermia, muscle rigidity, and elevated CK levels. Other frequently seen symptoms include altered mental status, tachypnea, tachycardia, elevated WBC count, hypotension, diaphoresis, and myoglobinuria. Our patient presented with 2 of the core symptoms, but did not develop muscle rigidity at any time. NMS criteria include muscle rigidity as one of the major presenting symptoms. Recent literature suggests that perhaps NMS due to novel antipsychotics presents with less muscle rigidity than is seen with traditional agents due to their lower affinity for the dopamine D2 receptor.

Conclusions:

This case illustrates that NMS due to the novel antipsychotic ziprasidone may present with many of the core symptoms of the syndrome, but possibly less muscle rigidity than is seen with traditional agents.

Use of Expert Consultation in a Complex Case of Neuroleptic Malignant Syndrome Requiring Electroconvulsive Therapy

Our team at Emory University Hospital contacted experts at the National Network of Depression Centers (NNDC) for clinical guidance concerning a patient with schizophrenia hospitalized in the intensive care unit with a complex case of prolonged delirium secondary to neuroleptic malignant syndrome (NMS). Through the NNDC, leading psychiatrists across the United States with expertise in electroconvulsive therapy (ECT) provided us with treatment strategies based on experience in our area of concern. This report describes our use of ECT to treat severe NMS in this patient with schizophrenia, utilizing the recommendations made by the NNDC's ECT experts concerning electrode position, number and frequency of treatments, and selection of anesthetic induction agents. This case report highlights the utility of expert consultation in the treatment of rare diseases and provides guidance on how to treat NMS in the intensive care unit setting.

Neuroleptic Malignant Syndrome Associated with Lithium Toxicity

Neuroleptic Malignant Syndrome (NMS) is an idiosyncratic and potentially life-threatening reaction to neuroleptic drugs. Lithium is a first-line mood stabilizer used in the treatment and prophylaxis of bipolar disorder. There are several case reports of lithium-associated NMS, but only when it was given in combination with antipsychotics. Therefore, the possibility of NMS being secondary to the antipsychotics could not be ruled out in those cases. Here we present a case of lithium-induced NMS in a patient who was not being treated concomitantly with any other agent known to cause NMS. The patient, a 74-year-old female with a 30-year history of bipolar affective disorder, was admitted to the emergency room of the All India Institute of Medical Sciences, New Delhi, with history of high fever and generalized weakness for 10 days before the admission. NMS was established based the presence of three cardinal symptoms. She was started on intravenous fluids to correct her sodium levels slowly and requested to follow-up at the psychiatry clinic.

Acute Dystonic Reaction and the Neuroleptic Malignant Syndrome

Up to 90% of patients on chronic antipsychotic therapy will experience adverse neurologic side effects, with many of these effects attributable to the dopamine-blocking properties of these drugs. Even the newer, “atypical” antipsychotics are increasingly associated with neurologic complications. In the acute care setting, these medications have broad application beyond the management of psychiatric illness. Given the extent of their use, clinicians should be familiar with the spectrum of neurological syndromes that can develop. Some are common, such as akathisia, acute dystonic reaction, tardive dyskinesia, and drug-induced parkinsonism. Others, such as the life-threatening neuroleptic malignant syndrome, are rare yet must be recognized early to affect survival and improve outcome. This discussion highlights 2 idiosyncratic syndromes, acute dystonic reaction and neuroleptic malignant syndrome. The differential diagnosis for both syndromes and their management is discussed.

Neuroleptic malignant syndrome in a patient treated with lithium carbonate and haloperidol

A 39-year-old female with a 20-year history of bipolar disorder was admitted due to a recurrence of a manic episode with psychotic symptoms. She was treated with standard doses of lithium carbonate and clozapine. Three days after admission, she showed aggressive behavior and refused to take her medications so her oral clozapine was switched to intramuscular haloperidol. Three days later she developed a high temperature and exhibited symptoms of neuroleptic malignant syndrome (NMS) including excessive sweating, cramps and tremors in limb muscles, muscle rigidity, and impaired consciousness. The haloperidol and lithium were stopped immediately, symptomatic treatment was provided, and she was administered the dopamine agonist bromocriptine. The NMS symptoms resolved within three days but she continued to have severe psychotic symptoms. She was subsequently re-challenged with valproate and olanzapine but the NMS did not re-occur. After one month of this treatment she recovered and was discharged. Several case histories similar to this one suggest – but do not prove – that individuals concurrently receiving lithium and antipsychotic medications may be at higher risk of developing NMS than those receiving monotherapy with antipsychotic medication.

Extracorporeal Treatment for Lithium Poisoning: Systematic Review and Recommendations from the EXTRIP Workgroup

The Extracorporeal Treatments in Poisoning Workgroup was created to provide evidence-based recommendations on the use of extracorporeal treatments in poisoning. Here, the EXTRIP workgroup presents its recommendations for lithium poisoning. After a systematic literature search, clinical and toxicokinetic data were extracted and summarized following a predetermined format. The entire workgroup voted through a two-round modified Delphi method to reach a consensus on voting statements. A RAND/UCLA Appropriateness Method was used to quantify disagreement, and anonymous votes were compiled and discussed in person. A second vote was conducted to determine the final workgroup recommendations. In total, 166 articles met inclusion criteria, which were mostly case reports, yielding a very low quality of evidence for all recommendations. A total of 418 patients were reviewed, 228 of which allowed extraction of patient-level data. The workgroup concluded that lithium is dialyzable (Level of evidence=A) and made the following recommendations: Extracorporeal treatment is recommended in severe lithium poisoning (1D). Extracorporeal treatment is recommended if kidney function is impaired and the [Li(+)] is >4.0 mEq/L, or in the presence of a decreased level of consciousness, seizures, or life-threatening dysrhythmias irrespective of the [Li(+)] (1D). Extracorporeal treatment is suggested if the [Li(+)] is >5.0 mEq/L, significant confusion is present, or the expected time to reduce the [Li(+)] to <1.0 mEq/L is >36 hours (2D). Extracorporeal treatment should be continued until clinical improvement is apparent or [Li(+)] is <1.0 mEq/L (1D). Extracorporeal treatments should be continued for a minimum of 6 hours if the [Li(+)] is not readily measurable (1D). Hemodialysis is the preferred extracorporeal treatment (1D), but continuous RRT is an acceptable alternative (1D). The workgroup supported the use of extracorporeal treatment in severe lithium poisoning. Clinical decisions on when to use extracorporeal treatment should take into account the [Li(+)], kidney function, pattern of lithium toxicity, patient's clinical status, and availability of extracorporeal treatments.

Neuroleptic malignant syndrome: a review for neurohospitalists

Neuroleptic malignant syndrome (NMS) is a life-threatening idiosyncratic reaction to antipsychotic drugs characterized by fever, altered mental status, muscle rigidity, and autonomic dysfunction. It has been associated with virtually all neuroleptics, including newer atypical antipsychotics, as well as a variety of other medications that affect central dopaminergic neurotransmission. Although uncommon, NMS remains a critical consideration in the differential diagnosis of patients presenting with fever and mental status changes because it requires prompt recognition to prevent significant morbidity and death. Treatment includes immediately stopping the offending agent and implementing supportive measures, as well as pharmacological interventions in more severe cases. Maintaining vigilant awareness of the clinical features of NMS to diagnose and treat the disorder early, however, remains the most important strategy by which physicians can keep mortality rates low and improve patient outcomes.

Antipsychotic dose escalation as a trigger for neuroleptic malignant syndrome (NMS): literature review and case series report

BACKGROUND

"Neuroleptic malignant syndrome" (NMS) is a potentially fatal idiosyncratic reaction to any medication which affects the central dopaminergic system. Between 0.5% and 1% of patients exposed to antipsychotics develop the condition. Mortality rates may be as high as 55% and many risk factors have been reported. Although rapid escalation of antipsychotic dose is thought to be an important risk factor, to date it has not been the focus of a published case series or scientifically defined.

DESCRIPTION

We aimed to identify cases of NMS and review risk factors for its development with a particular focus on rapid dose escalation in the 30 days prior to onset. A review of the literature on rapid dose escalation was undertaken and a pragmatic definition of "rapid dose escalation" was made. NMS cases were defined using DSM-IV criteria and systematically identified within a secondary care mental health service. A ratio of titration rate was calculated for each NMS patient and "rapid escalators" and "non rapid escalators" were compared. 13 cases of NMS were identified. A progressive mean dose increase 15 days prior to the confirmed episode of NMS was observed (241.7 mg/day during days 1-15 to 346.9 mg/day during days 16-30) and the mean ratio of dose escalation for NMS patients was 1.4. Rapid dose escalation was seen in 5/13 cases and non rapid escalators had markedly higher daily cumulative antipsychotic dose compared to rapid escalators.

CONCLUSIONS

Rapid dose escalation occurred in less than half of this case series (n = 5, 38.5%), although there is currently no consensus on the precise definition of rapid dose escalation. Cumulative antipsychotic dose - alongside other known risk factors - may also be important in the development of NMS.

Lithium toxicity and neurologic effects: probable neuroleptic malignant syndrome resulting from lithium toxicity

Introduction. We present the case of a patient who developed lithium toxicity with normal therapeutic levels, as a result of pharmacokinetic interaction with Valsartan, and probable Neuroleptic Malignant Syndrome from the ensuing lithium toxicity. Case Presentation. A 59-year old black male with bipolar disorder maintained on lithium and fluphenazine therapy presented with a 2 week history of worsening confusion, tremor, and gait abnormality. He recently had his dose of Valsartan increased. At presentation, patient had signs of autonomic instability, he was confused, dehydrated, and had rigidity of upper extremities. Significant labs on admission were lithium level-1.2, elevated CK-6008, leukocytosis WBC-22, and renal impairment; Creatinine-4.1, BUN-35, HCO₃-20.1, and blood glucose 145. CT/MRI brain showed old cerebral infarcts, and there was no evidence of an infective process. Lithium and fluphenazine were discontinued, his lithium levels gradually decreased, and he improved with supportive treatment including rehydration and correction of electrolyte imbalance. Conclusions. This case illustrates that lithium toxicity can occur within therapeutic levels, and the neurotoxic effect of lithium can include Neuroleptic Malignant Syndrome. Clinicians should be aware of the risk associated with drug interactions with lithium.

Neurological and cardiovascular adverse events associated with antimanic treatment in children and adolescents

To identify the factors associated with incident neurological and cardiovascular adverse events in children and adolescents treated with antimanic agents, a retrospective, longitudinal study was conducted. Medicaid medical and pharmacy claims between January 1996 and December 2005 were used to identify 3657 children and adolescents prescribed antimanic medications, and a random sample of 4500 children not treated with psychotropic medications. All adverse events examined (sedation/drowsiness, headaches, involuntary movements/extrapyramidal symptoms (EPS), cardiovascular events, hypertension, and orthostatic hypotension) were more prevalent in the antimanic-treated cohort. The odds of developing incident sedation/drowsiness and headaches were significantly higher for those prescribed carbamazepine, and co-prescribed selective serotonin reuptake inhibitors or antipsychotics. The odds of incident involuntary movements/EPS were significantly higher for those co-prescribed antimanic and antipsychotic agents, and those with comorbid central nervous system (CNS), organic brain disorders/mental retardation, or epilepsy. Incident cardiovascular events, hypertension, and orthostatic hypotension odds were significantly higher for those co-prescribed antimanic agents and antipsychotics, or those with comorbid epilepsy or metabolic conditions. Co-prescription of antimanic and antipsychotic agents is more likely associated with neurological and cardiovascular adverse reactions, especially in young patients with preexisting CNS/neurological disorders.

Catatonia, neuroleptics and brain damage--a case report

Catatonia is a syndrome that encompasses multiple motor signs. It can be the only presenting clinical feature in a patient with underlying multiple neuropsychiatric syndromes. The authors present a case of amisulpiride-induced catatonia, further evaluation suggested neuroleptic malignant syndrome (NMS) and showed the occurrence of temporal lobe epilepsy (TLE) and underlying brain pathology with marked frontoparietal atrophy and periventricular white matter hyperintensities. The pathological substrate of catatonia and its complex association with neuropsychiatric syndromes are discussed.

Lithium toxicity from an Internet dietary supplement

INTRODUCTION

The widespread availability of medications and herbal products on the Internet has increased the potential for poisonings. We are reporting a case of mild, acute lithium toxicity occurring after the intentional misuse of a lithium-containing "dietary supplement" (Find Serenity Now) obtained over the Internet.

CASE REPORT

An 18-year-old woman presented to our emergency department (ED) after ingesting 18 tablets of Find Serenity Now; each tablet contained, according to the listing, 120 mg of lithium orotate [3.83 mg of elemental lithium per 100 mg of (organic) lithium orotate compared to 18.8 mg of elemental lithium per 100 mg of (inorganic) lithium carbonate]. The patient complained of nausea and reported one episode of emesis. Her examination revealed normal vital signs. The only finding was a mild tremor without rigidity. Almost 90 minutes after the ingestion, her serum lithium level was 0.31 mEq/L, a urine drug screen was negative, and an electrocardiogram (ECG) showed a normal sinus rhythm. The patient received intravenous fluids and an anti-emetic; one hour later, her repeat serum lithium level was 0.40 mEq/L. After 3 hours of observation, nausea and tremor were resolved, and she was subsequently transferred to a psychiatric hospital for further care. Prior human and animal data have shown similar pharmacokinetics and shared clinical effects of these lithium salts.

DISCUSSION

Over-the-Internet dietary supplements may contain ingredients capable of causing toxicity in overdose. Chronic lithium toxicity from ingestion of this product is also of theoretical concern.

Effects of lithium on the human erythrocyte membrane and molecular models

The mechanism whereby lithium carbonate controls manic episodes and possibly influences affective disorders is not yet known. There is evidence, however, that lithium alters sodium transport and may interfere with ion exchange mechanisms and nerve conduction. For these reasons it was thought of interest to study its perturbing effects upon membrane structures. The effects of lithium carbonate (Li+) on the human erythrocyte membrane and molecular models have been investigated. The molecular models consisted in bilayers of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), representing classes of phospholipids located in the outer and inner monolayers of the erythrocyte membrane, respectively. This report presents the following evidence that Li+ interacts with cell membranes: a) X-ray diffraction indicated that Li+ induced structural perturbation of the polar head group and of the hydrophobic acyl regions of DMPC and DMPE; b) experiments performed on DMPC large unilamellar vesicles (LUV) by fluorescence spectroscopy also showed that Li+ interacted with the lipid polar groups and hydrophobic acyl chains, and c) in scanning electron microscopy (SEM) studies on intact human erythrocytes the formation of echinocytes was observed, effect that might be due to the insertion of Li+ in the outer monolayer of the red cell membrane.

Zotepine-induced catatonia as a precursor in the progression to neuroleptic malignant syndrome

A 39-year-old man with schizophrenia developed severe catatonia, hyperthermia, muscle rigidity, tachycardia, leukocytosis, and elevated muscle enzyme levels while receiving zotepine therapy. Neuroleptic malignant syndrome (NMS) was diagnosed. After withdrawal of zotepine therapy, transfer to a neurologic intensive care unit, provision of supportive care, and administration of adjunctive bromocriptine therapy, the patient's fever and catatonia subsided. Biochemical irregularities spontaneously returned to normal with no complications. Antipsychotic therapy was restarted with risperidone 12 days after the patient's NMS resolved. After more than 1 year of follow-up, he experienced no adverse events. A recent decrease in mortality from NMS is related to increased awareness of this disorder, but not to treatment with specific agents. Clinicians need to recognize NMS early; although rare, it is a potentially fatal complication of antipsychotic treatment.

Diagnosis and management of acute movement disorders

Most movement disorders, reflecting degenerative disorders, develop in a slowly progressive fashion. Some movement disorders, however, manifest with an acute onset. We wish to give an overview of the management and therapy of those acute-onset movement disorders.Drug-induced movement disorders are mainly caused by dopamine-receptor blockers (DRB) as used as antipsychotics (neuroleptics) and antiemetics. Acute dystonic reactions usually occur within the first four days of treatment. Typically, cranial pharyngeal and cervical muscles are affected. Anticholinergics produce a prompt relief. Akathisia is characterized by an often exceedingly bothersome feeling of restlessness and the inability to remain still. It is a common side effect of DRB and occurs within few days after their initiation. It subsides when DRB are ceased. Neuroleptic Malignant Syndrome is a rare, but life-threatening adverse reaction to DRB which may occur at any time during DRB application. It is characterised by hyperthermia, rigidity, reduced consciousness and autonomic failure. Therapeutically immediate DRB withdrawal is crucial. Additional dantrolene or bromocriptine application together with symptomatic treatment may be necessary. Paroxysmal dyskinesias are childhood onset disorders characterised by dystonic postures, chorea, athetosis and ballism occurring at irregular intervals. In Paroxysmal Kinesigenic Dyskinesia they are triggered by rapid movements, startle reactions or hyperventilation. They last up to 5 minutes, occur up to 100 times per day and are highly sensitive to anticonvulsants. In Paroxysmal Non-Kinesiogenic Dyskinesia they cannot be triggered, occur less frequently and last longer. Other paroxysmal dyskinesias include hypnogenic paroxysmal dyskinesias, paroxysmal exertional dyskinesia, infantile paroxysmal dystonias, Sandifer's syndrome and symptomatic paroxysmal dyskinesias. In Hereditary Episodic Ataxia Type 1 attacks of ataxia last for up to two minutes, may be accompanied by dysarthria and dystonia and usually respond to phenytoin. In Type 2 they can last for several hours, may be accompanied by vertigo, headache and malaise and usually respond to acetazolamide. Symptomatic episodic ataxias can occur in a number of metabolic disorders, but also in multiple sclerosis and Behcet's disease.

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).

The Effects of Drugs on Thermoregulation

Body temperature is a balance of the hypothalamic set point, neurotransmitter action, generation of body heat, and dissipation of heat. Drugs affect body temperature by different mechanisms. Antipyretics lower body temperature when the body's thermoregulatory set point has been raised by endogenous or exogenous pyrogens. The use of antipyretics may be unnecessary or may interfere with the body's resistance to infection, mask an important sign of illness, or cause adverse drug effects. Drugs may cause increased body temperature in five ways: altered thermoregulatory mechanisms, drug administration-related fever, fever from the pharmacologic action of the drug, idiosyncratic reactions, and hypersensitivity reactions. Certain drugs cause hypothermia by depression of the thermoregulatory set point or prevention of heat conservation. By affecting the balance of thermoregulatory neurotransmitters, drugs may prevent the signs and symptoms of hot flashes.