Hypothermia due to Antipsychotic Medication: A Systematic Review

The role of psychotropics on the associations between extreme temperature and heat-related outcomes among people with mental health conditions: population-based study

BACKGROUND

The association between heatwave and heat-related outcomes in people with mental health conditions with and without psychotropics was unclear.

METHODS

We identified people with severe mental illness (SMI) and depression, respectively, using Japanese claim data of Ibaraki prefecture during 1/1/2014-31/12/2021. We conducted self-controlled case series to estimate the incidence rate ratio (IRR) of heat-related illness, myocardial infarction and delirium, respectively, during 5-day pre-heatwave, heatwave, and 5-day post-heatwave periods v. all other periods (baseline) within an individual, stratified by periods prescribed psychotropics and periods not prescribed psychotropics, respectively.

RESULTS

Among people with SMI, heatwave was associated with an increased rate of heat-related illness v. baseline, with no evidence of a difference in the IRRs between those prescribed v. not prescribed antipsychotics (IRR: 1.48 [95% CI 1.40-1.56]; 1.45 [95% CI 1.35-1.56] respectively, p interaction: 0.53). Among people with depression, heatwave was similarly associated with heat-related illness, with no evidence of a difference in the IRRs between those prescribed v. not prescribed antidepressants (IRR: 1.54 [95% CI 1.46-1.64]; 1.64 [95% CI 1.57-1.71] respectively, p interaction: 0.33). Smaller increased rates of heat-related illness were also observed in pre- and post-heatwave periods, v. baseline in both cohorts. There was weak evidence of an increased risk of MI and delirium associated with heatwave v. baseline.

CONCLUSIONS

We showed an increased risk of heat-related illness, myocardial infarction and delirium associated with heatwave in people with mental health conditions regardless of whether being prescribed psychotropics. Risks of heat-related illness, myocardial infarction and delirium associated with heatwave might not be factors to influence decisions about the routine use of psychotropics.

Synergistic rescue of temperature-sensitive p53 mutants by hypothermia and arsenic trioxide

The p53 tumor suppressor is inactivated by mutations in about 50% of tumors. Rescuing the transcriptional function of mutant p53 has potential therapeutic benefits. Approximately 15% of p53 mutants are temperature sensitive (TS) and regain maximal activity at 32°C. Proof of concept study showed that induction of 32°C hypothermia in mice restored TS mutant p53 activity and inhibited tumor growth. However, 32°C is the lower limit of therapeutic hypothermia procedures for humans. Higher temperatures are preferable but result in suboptimal TS p53 activation. Recently, arsenic trioxide (ATO) was shown to rescue the conformation of p53 structural mutants by stabilizing the DNA binding domain. We examined the responses of 17 frequently observed p53 TS mutants to functional rescue by temperature shift and ATO. The results showed that ATO only rescued mild p53 TS mutants with high basal activity at 37°C. Mild TS mutants showed a common feature of regaining significant activity at the semi-permissive temperature of 35°C and could be further stimulated by ATO at 35°C. TS p53 rescue by ATO was antagonized by the cellular redox mechanism and was rapidly reversible. Inhibition of glutathione (GSH) biosynthesis enhanced ATO rescue efficiency and sustained p53 activity after ATO washout. The results suggest that mild TS p53 mutants are uniquely responsive to functional rescue by ATO due to small thermostability deficits and inherent potential to regain active conformation. Combining mild hypothermia and ATO may provide an effective and safe procedure for targeting tumors with p53 TS mutations.

Successful Treatment of Risperidone-Induced Hypothermia With Aripiprazole: A Brief Case Report and a Literature Review

Hypothermia, a potentially fatal condition, can result from various internal causes, including certain medications. Antipsychotics, in particular, are associated with hypothermia, typically emerging 7-10 days after dosage adjustments. Here, we report the case of a 68-year-old male with a history of cerebral palsy, bipolar disorder, and paranoid schizophrenia who was admitted due to poor oral intake and was found to have persistent hypothermia despite active external rewarming. After substituting risperidone with aripiprazole, his temperature normalized, and he experienced no further hypothermic episodes.  Antipsychotic-induced hypothermia should be considered in patients on these medications who present with non-specific symptoms. Regular monitoring of temperature and vital signs is crucial for early detection and management.

Neural cell-types and circuits linking thermoregulation and social behavior

Understanding how social and affective behavioral states are controlled by neural circuits is a fundamental challenge in neurobiology. Despite increasing understanding of central circuits governing prosocial and agonistic interactions, how bodily autonomic processes regulate these behaviors is less resolved. Thermoregulation is vital for maintaining homeostasis, but also associated with cognitive, physical, affective, and behavioral states. Here, we posit that adjusting body temperature may be integral to the appropriate expression of social behavior and argue that understanding neural links between behavior and thermoregulation is timely. First, changes in behavioral states-including social interaction-often accompany changes in body temperature. Second, recent work has uncovered neural populations controlling both thermoregulatory and social behavioral pathways. We identify additional neural populations that, in separate studies, control social behavior and thermoregulation, and highlight their relevance to human and animal studies. Third, dysregulation of body temperature is linked to human neuropsychiatric disorders. Although body temperature is a "hidden state" in many neurobiological studies, it likely plays an underappreciated role in regulating social and affective states.

The future of artificial hibernation medicine: protection of nerves and organs after spinal cord injury

Spinal cord injury is a serious disease of the central nervous system involving irreversible nerve injury and various organ system injuries. At present, no effective clinical treatment exists. As one of the artificial hibernation techniques, mild hypothermia has preliminarily confirmed its clinical effect on spinal cord injury. However, its technical defects and barriers, along with serious clinical side effects, restrict its clinical application for spinal cord injury. Artificial hibernation is a future-oriented disruptive technology for human life support. It involves endogenous hibernation inducers and hibernation-related central neuromodulation that activate particular neurons, reduce the central constant temperature setting point, disrupt the normal constant body temperature, make the body "adapt" to the external cold environment, and reduce the physiological resistance to cold stimulation. Thus, studying the artificial hibernation mechanism may help develop new treatment strategies more suitable for clinical use than the cooling method of mild hypothermia technology. This review introduces artificial hibernation technologies, including mild hypothermia technology, hibernation inducers, and hibernation-related central neuromodulation technology. It summarizes the relevant research on hypothermia and hibernation for organ and nerve protection. These studies show that artificial hibernation technologies have therapeutic significance on nerve injury after spinal cord injury through inflammatory inhibition, immunosuppression, oxidative defense, and possible central protection. It also promotes the repair and protection of respiratory and digestive, cardiovascular, locomotor, urinary, and endocrine systems. This review provides new insights for the clinical treatment of nerve and multiple organ protection after spinal cord injury thanks to artificial hibernation. At present, artificial hibernation technology is not mature, and research faces various challenges. Nevertheless, the effort is worthwhile for the future development of medicine.

Combined effects of methadone and quetiapine on respiratory rate, haemodynamic variables, and temperature in conscious rats

Fatal poisonings where both methadone and quetiapine are detected post-mortem occurs frequently in legal autopsy cases. It is unclear whether quetiapine increases the risk of fatal methadone poisoning or if it is merely detected due to widespread use. We hypothesized that methadone and quetiapine would have additive toxic effects on respiratory rate, blood pressure, and the QTc-interval. To investigate this hypothesis, we used telemetry implants for measurements of respiratory rate, haemodynamic variables, the velocity of blood pressure changes, temperature, and movement in conscious, freely moving male Wistar rats aged 12-13 weeks. The combined effects of three accumulative i.p. doses of methadone (2.5, 10, 15 mg/kg) and quetiapine (3, 10, 30 mg/kg) were compared to rats treated with the same doses of each drug alone, and a vehicle-treated group in a randomized investigator blinded study. No additive effects of quetiapine and methadone on respiratory rate, haemodynamic variables, or movement were observed. However, body temperature was significantly lower by approximately 1.5°C on average in the group treated with both methadone and quetiapine (15 + 30 mg/kg) compared to the other groups. This indicates a synergistic effect of quetiapine and methadone on thermoregulation, which may increase the risk of fatal poisoning. We suggest studying this finding further in human settings.

Identifying Risk Factors for Hospitalization with Behavioral Health Disorders and Concurrent Temperature-Related Illness in New York State

Extreme temperature events are linked to increased emergency department visits, hospitalizations, and mortality for individuals with behavioral health disorders (BHD). This study aims to characterize risk factors for concurrent temperature-related illness among BHD hospitalizations in New York State. Using data from the NYS Statewide and Planning Research and Cooperative System between 2005-2019, multivariate log binomial regression models were used in a population of BHD hospitalizations to estimate risk ratios (RR) for a concurrent heat-related (HRI) or cold-related illness (CRI). Dementia (RR 1.65; 95% CI:1.49, 1.83) and schizophrenia (RR 1.38; 95% CI:1.19, 1.60) were associated with an increased risk for HRI among BHD hospitalizations, while alcohol dependence (RR 2.10; 95% CI:1.99, 2.22), dementia (RR 1.52; 95% CI:1.44, 1.60), schizophrenia (RR 1.41; 95% CI:1.31, 1.52), and non-dependent drug/alcohol use (RR 1.20; 95% CI:1.15, 1.26) were associated with an increased risk of CRI among BHD hospitalizations. Risk factors for concurrent HRI among BHD hospitalizations include increasing age, male gender, non-Hispanic Black race, and medium hospital size. Risk factors for concurrent CRI among BHD hospitalizations include increasing age, male gender, non-Hispanic Black race, insurance payor, the presence of respiratory disease, and rural hospital location. This study adds to the literature by identifying dementia, schizophrenia, substance-use disorders, including alcohol dependence and non-dependent substance-use, and other sociodemographic factors as risk factors for a concurrent CRI in BHD hospitalizations.

The relationship of antipsychotic treatment with reduced brown adipose tissue activity in patients with schizophrenia

BACKGROUND

Antipsychotic drug (APD) treatment has been associated with metabolic abnormalities. Brown adipose tissue (BAT) is the main site of adaptive thermogenesis and secretes various metabolism-improving factors known as batokines. We explored the association of BAT activity with APD treatment and metabolic abnormalities in patients with schizophrenia by measuring the blood levels of bone morphogenetic protein 8b (BMP8b), a batokine secreted by mature BAT.

METHODS

BMP8b levels were compared among 50 drug-free, 32 aripiprazole-treated, and 91 clozapine-treated patients with schizophrenia. Regression analysis was used to explore factors, including APD types, that might be associated with BMP8b levels and the potential effect of BMP8b on metabolic syndrome (MS).

RESULTS

APD-treated patients had decreased BMP8b levels relative to drug-free patients. The difference still existed after adjustment for body mass index and Brief Psychiatric Rating Scale scores. Among APD-treated group, clozapine was associated with even lower BMP8b levels than the less obesogenic APD, aripiprazole. Furthermore, higher BMP8b levels were associated with lower risks of MS after adjustment for BMI and APD treatment.

CONCLUSION

Using drug-free patients as the comparison group to understand the effect of APDs, this is the first study to show APD treatment is associated with reduced BAT activity that is measured by BMP8b levels, with clozapine associated a more significant reduction than aripiprazole treatment. BMP8b might have a beneficial effect against metabolic abnormalities and this effect is independent of APD treatment. Future studies exploring the causal relationship between APD treatment and BMP8b levels and the underlying mechanisms are warranted.

Pediatric Environmental Cold Injuries

Cold weather injuries are relevant concerns for children during winter sports and outdoor activities. To mitigate the risk of cold injury in this high-risk population, providers can educate parents on proper outdoor attire as well as the added risks of wind and water exposure. There are 2 types of environmental cold injuries: freezing injuries and nonfreezing injuries. Frostbite is a freezing injury from direct contact with cold air or surfaces. The extent of injury depends on the depth to which the freezing extends. Treatment involves rewarming the frozen tissue with warm water baths and considering analgesia. Hypothermia is a nonfreezing cold injury, and it can occur even when ambient temperatures are above freezing. When there is a decrease in the body's core temperature, hypothermia progresses from mild to severe symptoms. Treatment of hypothermia is threefold but is also dependent on the core body temperature, as colder core temperatures will require more aggressive warming techniques. Hypothermia treatment involves passive protection from further heat loss (ie, removing wet clothing), which helps the body to warm itself. Treatment also involves active external rewarming wherein a heat source, such as a heated blanket, is used to increase body temperature. Active internal rewarming is the delivery of heat inside the patient's body, such as warmed intravenous fluids.

Characteristics of antipsychotic drug-induced hypothermia in psychogeriatric inpatients

OBJECTIVE

Hypothermia is a potentially lethal adverse reaction to typical and atypical antipsychotic drugs (APD). Among predisposing factors are advanced age and comorbid somatic diseases. The aim of this study was to assess the incidence of hypothermia and quantify risk factors.

METHOD

Charts of N = 3002 psychogeriatric inpatients were screened for incidence of hypothermia (body core temperature <35.0°C). The frequency of hypothermia was compared between patients treated with versus without APD and, within the sample of APD-treated patients, for (1) specific APD, (2) sex, (3) main diagnosis, and (4) age.

RESULTS

N = 54 cases (2.6%) of hypothermia occurred in APD-treated patients and 12 cases (1.3%) in non-APD-treated patients (p = 0.024). In APD-treated patients, only male sex (p = 0.038) and pipamperone were associated with a higher incidence of hypothermia (p = 0.0017). Whereas the main diagnosis delirium showed a trend to significance, age did not correlate with hypothermia.

CONCLUSION

Medication with pipamperone was associated with an increased risk of hypothermia. The advanced age of our sample might as well explain the high incidence of hypothermia within our sample and the failure to detect high age as a risk factor due to a ceiling effect.

Olanzapine-Induced Therapeutic Hypothermia Attenuates Renal Injury in Rats after Asphyxial Cardiac Arrest and Resuscitation

Return of spontaneous circulation (ROSC) through cardiopulmonary resuscitation (CPR) after cardiac arrest (CA) causes post-cardiac arrest syndrome (PCAS) due to dysfunction in various organs, which provokes acute kidney injury because of renal ischemia-reperfusion injury. Therapeutic hypothermia (TH) can reduce PCAS after CA and ROSC. However, it needs to be more sophisticated and effective. Hence, we aimed to elucidate the protective effects of olanzapine-induced TH against renal injury in asphyxial CA-induced rats. Every rat’s body temperature was maintained at 33 °C for 6 h after administering olanzapine post-CA and ROSC. Olanzapine-induced TH dramatically increased the survival rate of the rats and ameliorated renal tissue damage. Moreover, it suppressed oxidative stress responses through preservation of mitochondrial function and endoplasmic reticulum stress as the main contributor of oxidative stress. Notably, these actions of olanzapine-induced TH were mediated through the Sirt3-related signaling pathway, including the maintenance of Sirt3 and FOXO3a protein expression and the activation of AMPKα and superoxide dismutase 1 (SOD2, a mitochondrial antioxidant). This study is the first to disclose the protective effects of olanzapine-induced TH against renal injury after CA and ROSC, suggesting that olanzapine-induced TH could be utilized for treating CA followed by ROSC.

Possible Aripiprazole-Induced Hypothermia: An "Icy" Side Effect?

Antipsychotics are a widely used class of drugs. They have been frequently associated with temperature dysregulation, especially hyperthermia. Hypothermia is also a rare but very serious side effect associated with these drugs. We present a case of possible aripiprazole-induced hypothermia with normothermia achieved after its discontinuation. An 81-year-old woman was brought into the emergency room with hypotension, hypothermia, and bradycardia. She was initially managed with intravenous fluids, external rewarming, and broad-spectrum antibiotics. Blood cultures and workup for infection returned negative with a low procalcitonin. Workup for endocrinopathy was also negative. She needed a Bair Hugger™ (3M, Maplewood, MN) to keep her temperature above 36 °C even after her other vital signs had normalized. Finally, her aripiprazole was held with the suspicion that it was causing hypothermia. Following this, her temperature improved and remained stable throughout even after discharge. Since hypothermia can be life-threatening, after ruling out common causes, clinicians should consider aripiprazole-induced hypothermia in these patients and the drug should be promptly discontinued.

Housing Temperature Influences Atypical Antipsychotic Drug-Induced Bone Loss in Female C57BL/6J Mice

Atypical antipsychotic (AA) drugs, such as risperidone, are associated with endocrine and metabolic side effects, including impaired bone mineral density (BMD) acquisition and increased fracture risk. We have previously shown that risperidone causes bone loss through the sympathetic nervous system and that bone loss is associated with elevated markers of thermogenesis in brown and white adipose tissue. Because rodents are normally housed in sub‐thermoneutral conditions, we wanted to test whether increasing housing temperature would protect against bone loss from risperidone. Four weeks of risperidone treatment in female C57BL/6J mice at thermoneutral (28°C) housing attenuated risperidone‐induced trabecular bone loss and led to a low‐turnover bone phenotype, with indices of both bone formation and resorption suppressed in mice with risperidone treatment at thermoneutrality, whereas indices of bone resorption were elevated by risperidone at room temperature. Protection against trabecular bone loss was not absolute, however, and additional evidence of cortical bone loss emerged in risperidone‐treated mice at thermoneutrality. Taken together, these findings suggest thermal challenge may be in part responsible for bone loss with risperidone treatment and that housing temperature should be considered when assessing bone outcomes of treatments that impact thermogenic pathways. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Perioperative Hypothermia-A Narrative Review

Unintentional hypothermia (core temperature < 36 °C) is a common side effect in patients undergoing surgery. Several patient-centred and external factors, e.g., drugs, comorbidities, trauma, environmental temperature, type of anaesthesia, as well as extent and duration of surgery, influence core temperature. Perioperative hypothermia has negative effects on coagulation, blood loss and transfusion requirements, metabolization of drugs, surgical site infections, and discharge from the post-anaesthesia care unit. Therefore, active temperature management is required in the pre-, intra-, and postoperative period to diminish the risks of perioperative hypothermia. Temperature measurement should be done with accurate and continuous probes. Perioperative temperature management includes a bundle of warming tools adapted to individual needs and local circumstances. Warming blankets and mattresses as well as the administration of properly warmed infusions via dedicated devices are important for this purpose. Temperature management should follow checklists and be individualized to the patient's requirements and the local possibilities.

The use of melatonin to mitigate the adverse metabolic side effects of antipsychotics

Antipsychotic drugs are efficacious first-line treatments for many individuals diagnosed with a psychiatric illness. However, their adverse metabolic side-effect profile, which resembles the metabolic syndrome, represents a significant clinical problem that increases morbidity and limits treatment adherence. Moreover, the mechanisms involved in antipsychotic-induced adverse metabolic effects (AMEs) are unknown and mitigating strategies and interventions are limited. However, recent clinical trials show that nightly administration of exogenous melatonin may mitigate or even prevent antipsychotic-induced AMEs. This clinical evidence in combination with recent preclinical data implicate the circadian system in antipsychotic-induced AMEs and their mitigation. In this chapter, we provide an overview on the circadian system and its involvement in antipsychotic-induced AMEs, as well as the potential beneficial effect of nightly melatonin administration to mitigate them.

From general toxicology to DNA disruption: A safety assessment of Plinia cauliflora (Mart.) Kausel

ETHNOPHARMACOLOGICAL RELEVANCE

Plinia cauliflora (Mart.) Kausel (Myrtaceae) is popularly known as "jaboticaba" or "jaboticaba". The fruit is appreciated for both fresh consumption and the manufacture of jelly, juice, ice cream, fermented beverages, and liqueurs. The more widespread traditional use of the plant involves the treatment of diarrhea, which utilizes all parts of the plant, including the fruit peels.

AIM OF THE STUDY

We sought to elucidate possible risks of the administration of an ethanol-soluble fraction that was obtained from an infusion of P. cauliflora fruit peels (SEIPC). We performed a series of experiments to evaluate possible toxicity, in which we administered SEIPC orally both acutely and repeatedly for 28 days. We also evaluated possible endocrine-disruptive and genotoxic effects in eukaryotic cells. The possible mutagenic activity of SEIPC was evaluated using reverse mutation (Ames) assays.

MATERIALS AND METHODS

SEIPC was produced and chemically characterized by LC-DAD-MS. Acute toxicity and behavioral and physiological alterations were evaluated in the modified Irwin test. Respiratory rate, arterial blood gas, electrocardiography, respiratory rate, heart rate, and blood pressure were evaluated, and hematological, biochemical, and histopathological analyses were performed after 28 days of oral treatment. The comet assay, mammalian erythrocyte micronucleus test, uterotrophic test, Hershberger bioassay, and AMES test were performed using appropriate protocols.

RESULTS

From SEIPC, ellagic acid and derivatives, flavonols and anthocyanidins, as well as citric acid and gallic acid, were annotated by LC-DAD-MS. We did not observed any significant toxic effects after acute or prolonged SEIPC treatment. No endocrine-disruptive or mutagenic effects were observed.

CONCLUSIONS

The present study found that SEIPC did not cause any significant alterations of various corporeal systems, including cardiac electrical activity, body temperature, respiratory rate, and arterial pressure. No alterations of biochemical, hematological, or blood gas parameters were observed. SEIPC did not cause any perturbations of the endocrine system or mutagenic, cytotoxic, or genotoxic effects. These findings substantiate the safe clinical use of P. cauliflora.

A case report of acute hypothermia during initial inpatient clozapine titration with review of current literature on clozapine-induced temperature dysregulations

BACKGROUND

Here we describe a unique case of clozapine-associated hypothermia during initial titration of this medication in an acute inpatient psychiatry setting. Only a handful of cases on this topic have been published. We discuss possible pharmacologic mechanisms supporting or refuting the propensity of clozapine to induce hypothermia, as well as risk factors for clozapine-induced hypothermia, and a comparison to clozapine-induced hyperthermia.

CASE PRESENTATION

A 70 year-old African American female with treatment-refractory schizoaffective disorder developed hypothermia with a nadir temperature of 89 °F (31.7 °C) after 7 days on clozapine, on a total dose of 50 mg twice daily. Accompanying symptoms included bradycardia, hypotension, QTc prolongation, tachypnea, hypoxemia, and an absence of shivering. The patient was transferred to the ICU, and rewarmed within 10 h with the discontinuation of her clozapine, ziprasidone, and carvedilol. Broad spectrum antibiotics were initiated, but discontinued shortly after, as the patient had no leukocytosis, and blood cultures were negative.

DISCUSSION

While hypoglycemia, hypothyroidism, sepsis, and stroke were effectively ruled out, alternative drug-disease (including chronic kidney disease), and drug-drug interactions were considered possible contributing features. Benzodiazepines, valproic acid, ziprasidone, and the numerous antihypertensive agents the patient was taking were considered as either primary or compounding factors for hypothermia. After exclusion or inclusion of these alternative causes, we calculated a score of 4 (possible) for clozapine-induced hypothermia on the Naranjo Scale.

CONCLUSIONS

Clozapine-induced hypothermia may occur more commonly than clinicians believe. Practitioners should be cognizant of this potentially fatal phenomenon, and monitor for temperature dysregulations while on clozapine, especially during initial titration, in those with multiple comorbid factors, and on additional medications that may contribute to hypothermia.

Severe hypothermia, bradycardia and cardiac arrest in association with risperidone

Antipsychotic medications, including risperidone, are widely used in the treatment of psychiatric disorders, including schizophrenia. While hyperthermia is an establish adverse effect of these medications, less is known about the rare occurrence of hypothermia. We present two patients who developed hypothermia, bradycardia and cardiac arrest in association with risperidone. We briefly review previously similarly reported cases.

Risperidone Treatment after Transient Ischemia Induces Hypothermia and Provides Neuroprotection in the Gerbil Hippocampus by Decreasing Oxidative Stress

Compelling evidence from preclinical and clinical studies has shown that mild hypothermia is neuroprotective against ischemic stroke. We investigated the neuroprotective effect of post-risperidone (RIS) treatment against transient ischemic injury and its mechanisms in the gerbil brain. Transient ischemia (TI) was induced in the telencephalon by bilateral common carotid artery occlusion (BCCAO) for 5 min under normothermic condition (37 ± 0.2 °C). Treatment of RIS induced hypothermia until 12 h after TI in the TI-induced animals under uncontrolled body temperature (UBT) compared to that under controlled body temperature (CBT) (about 37 °C). Neuroprotective effect was statistically significant when we used 5 and 10 mg/kg doses (p < 0.05, respectively). In the RIS-treated TI group, many CA1 pyramidal neurons of the hippocampus survived under UBT compared to those under CBT. In this group under UBT, post-treatment with RIS to TI-induced animals markedly attenuated the activation of glial cells, an increase of oxidative stress markers [dihydroethidium, 8-hydroxy-2' -deoxyguanosine (8-OHdG), and 4-Hydroxynonenal (4-HNE)], and a decrease of superoxide dismutase 2 (SOD2) in their CA1 pyramidal neurons. Furthermore, RIS-induced hypothermia was significantly interrupted by NBOH-2C-CN hydrochloride (a selective 5-HT_2A receptor agonist), but not bromocriptine mesylate (a D₂ receptor agonist). Our findings indicate that RIS-induced hypothermia can effectively protect neuronal cell death from TI injury through attenuation of glial activation and maintenance of antioxidants, showing that 5-HT_2A receptor is involved in RIS-induced hypothermia. Therefore, RIS could be introduced to reduce body temperature rapidly and might be applied to patients for hypothermic therapy following ischemic stroke.

Psycho-physiological response to pain among individuals with comorbid pain and opioid use disorder: Implications for patients with prolonged abstinence

Background: Individuals with comorbid opioid addiction and pain (COAP) relapse 3-5 times more often than patients with opioid use disorder (OUD) but without pain. However, psychophysiological responses to pain among a COAP population are unknown. Objectives: We hypothesized that those on Medications for Opioid Use Disorder (MOUD) with chronic pain, relative to opioid-naïve chronic pain individuals, would show greater psycho-physiological pain reactivity and slower recovery when exposed to acute pain. Methods: Four groups with chronic pain were recruited (N = 120; 60% Female): 1) MOUD-methadone; 2) MOUD-buprenorphine; 3) history of completed MOUD with prolonged opioid abstinence (PA; M_abstinence = 121 weeks; SD = 23.3); and 4) opioid-naïve. We assessed heart rate (HR), galvanic skin conductance (GSC), peripheral temperature, and frontalis electromyography (EMG) during a cold pain task. Results: MOUD subjects had delayed HR reactivity to pain compared to those not on MOUD (PA & opioid-naïve; F(3,119) = 2.87, p < .04). The PA group showed a normal HR reactivity pattern, but had higher HR compared to the opioid-naïve group. The GSC group x time analysis showed the PA group had greater baseline levels and pain reactivity than the other groups (F(3,119) = 3.84, p < .02). The opioid-naïve group had lower reactivity on peripheral temperature compared to other groups (F(3,119) = 9.69, p < .001). Conclusion: Greater psychophysiological reactivity to pain was experienced by co-morbid OUD/chronic pain subjects who had been opioid abstinent for an extended period, possibly due to the lack of a buffering effect of opioid agonists. These subjects may develop coping skills to tolerate pain distress, thereby avoiding relapse in response to pain triggers. Understanding how pain creates more intense psychophysiological responses among COAP patients may lead to better treatments.

Antipsychotic-Related Hypothermia: Five New Cases

Background: Hypothermia is a potentially fatal adverse effect of antipsychotic drug (APD) use. With only 69 cases described in the literature, the condition is considered rare. Methods: We describe five new cases, in which we estimated the role of clozapine, haloperidol, olanzapine, penfluridol, risperidone, and zuclopentixol with the aid of two structured assessment tools. Results: In addition to APD use, all five patients described by us had been exposed to one or more additional predisposing factors for hypothermia. Therefore, with the aid of the assessment tools, the causal role of APDs was considered "possible" in four cases of moderate hypothermia and "doubtful" in the remaining one of mild hypothermia. Conclusion: Although the best way to detect APD-related hypothermia is measuring the body temperature for a duration of at least 7-10 days after the start (or a dose increase) of APDs, the use of assessment tools to identify additional predisposing factors for hypothermia and to thus establish their causal relationship with APD use would seem to be valuable for clinical decision-making (i.e., whether or not to discontinue APD use). Further research is needed to obtain reliable prevalence figures for APD-related hypothermia and its consequences, preferably in relation with physiological changes in body temperature.

The risk factors, frequency and diagnosis of atypical antipsychotic drug-induced hypothermia: practical advice for doctors

Hypothermia is unpredictable and life-threatening adverse effect of atypical antipsychotic drug (APD) treatment, which has been little described. The aim of this article is to increase the awareness that hypothermia induced by APD drugs is more common than the current published case reports may suggest, and risk factors increase its development. Moreover, valuable guidelines regarding how to detect the early stages of hypothermia in clinical practice are included. A literature search for reports on APD-induced hypothermia in PubMed, Academic Search Complete, Medline Complete and eHealthMe databases was conducted. The literature search apart from eHealthMe database resulted in 524 articles, which included 34 case reports. Hypothermia was mostly induced by olanzapine (14) and risperidone (10). However, the data from Food and Drug Administration reports revealed several dozen more cases of APD-induced hypothermia (591case reports) compared with the published case reports (e.g. olanzapine-262 and risperidone-161). Hypothermia, mostly mild (61% of cases), has developed mainly in men (71%) having schizophrenia, a few hours after commencement of treatment or in the presence of risk factors. Owing to the increased risk of hypothermia development during APD treatment, doctors should routinely measure body temperature of patients, especially during the first days of the therapy. Early diagnosis of hypothermia and appropriate treatment may prevent death.

Gold nanorods together with HSP inhibitor-VER-155008 micelles for colon cancer mild-temperature photothermal therapy

Enhancing the heat-sensitivity of tumor cells provides an alternative solution to maintaining the therapeutic outcome of photothermal therapy (PTT). In this study, we constructed a therapeutic system, which was composed of methoxy-polyethylene-glycol-coated-gold-nanorods (MPEG-AuNR) and VER-155008-micelles, to evaluate the effect of VER-155008 on the sensitivity of tumor cells to heat, and further investigate the therapeutic outcome of MPEG-AuNR mediated PTT combined with VER-155008- micelles. VER-155008- micelles down-regulate the expression of heat shock proteins and attenuate the heat-resistance of tumor cell. The survival of HCT116 cells treated with VER-155008- micelles under 45 °C is equal to that treated with high temperature hyperthermia (55 °C) in vitro. Furthermore, we proved either the MPEG-AuNR or VER-155008- micelles can be accumulate in the tumor site by photoacoustic imaging and fluorescent imaging. In vivo anti-cancer evaluation showed that tumor size remarkably decreased (smaller than 100 mm³ or vanished) when treated with combing 45 °C mild PTT system, which contrasted to the tumor size when treated with individual 45 °C mild PTT (around 500 nm³) or normal saline as control (larger than 2000 nm³). These results proved that the VER-155008- micelles can attenuate the heat-resistance of tumor cells and enhance the therapeutic outcome of mild-temperature photothermal therapy.