Risk of death related to psychotropic drug use in older people during the European 2003 heatwave: a population-based case-control study.

OBJECTIVE: The authors investigated the association between death of older people and use of psychotropic drugs before and during the Western European August 2003 heatwave. METHOD: A retrospective population-based case-control study was conducted using the French social security insurance national database. Exposure to psychotropic drugs in cases aged 70-100 years who died before (N = 2,093) and during (N = 9,531) the August 2003 heatwave was compared with those of survivors matched for age, gender, and presence of chronic illness, by using conditional logistic regressions. RESULTS: The association between death and psychotropic drug use was modified by level of external temperature (Wald chi(2) = 13.1, degree of freedom = 1, p <0.001). Use of any psychotropic drug was associated with a 30% increased risk of death during the heatwave, with a significant dose-response relationship between the number of psychotropic drugs and the risk of death (adjusted odds ratio [aOR] for linear trend 1.25, 95% confidence interval [95% CI]: 1.21-1.29). During the heatwave, therapeutic classes independently associated with an increased risk of death were antidepressants (aOR 1.71, 95% CI: 1.57-1.86) and antipsychotics (aOR 2.09, 95% CI: 1.89-2.35), whereas exposure to anxiolytics/hypnotics use (aOR 0.85, 0.79-0.91) was associated with a decreased risk. Findings remained unchanged after adjustment on cardiotropic, antidementia, or anti-parkinsonian drug use. CONCLUSION: Our findings suggest that a causal relationship may exist between psychotropic drug use during a heatwave and increased risk of death in older people. The risk/benefit ratio of antidepressant and antipsychotic drugs should be carefully assessed in older people during a heatwave.

Heat-related side-effects of neurological and non-neurological medication may increase heatwave fatalities.

BACKGROUND: During the 2003 French heatwave 15,000 excess deaths were registered. One fifths died from the combination of dehydration, heatstroke, and hyperthermia and one tenth from dehydration, despite abundant water. METHODS AND RESULTS: We hypothesized that physiologic adaptation to heat was not effective in the victims attributable to side-effects of drugs (impaired thermoregulation, suppressed thirst) many of these patients were taking. This could explain why many victims died of dehydration despite availability of water. As a consequence of the global climate change heatwaves may occur more frequently and may be more intense, with a strong impact on the future selection of drugs in elderly patients. CONCLUSION: Insufficient water intake, impaired thermoregulation, and resulting death may be directly linked to the use of certain drugs, implying an immediate need for public awareness during heatwaves and for long-term strategies to mitigate the expected increase in future heatwave-related fatalities.

Nanoparticles aggravate heat stress induced cognitive deficits, blood-brain barrier disruption, edema formation and brain pathology.

Our knowledge regarding the influence of nanoparticles on brain function in vivo during normal or hyperthermic conditions is still lacking. Few reports indicate that when nanoparticles enter into the central nervous system (CNS) they may induce neurotoxicity. On the other hand, nanoparticle-induced drug delivery to the brain enhances neurorepair processes. Thus, it is likely that the inclusion of nanoparticles in body fluid compartments alters the normal brain function and/or its response to additional stress, e.g., hyperthermia. New data from our laboratory show that nanoparticles derived from metals (e.g., Cu, Ag or Al, approximately 50-60nm) are capable of inducing brain dysfunction in normal animals and aggravating the brain pathology caused by whole-body hyperthermia (WBH). Thus, normal animals treated with nanoparticles (for 1 week) exhibited mild cognitive impairment and cellular alterations in the brain. Subjection of these nanoparticle-treated rats to WBH resulted in profound cognitive and motor deficits, exacerbation of blood-brain barrier (BBB) disruption, edema formation and brain pathology compared with naive animals. These novel observations suggest that nanoparticles enhance brain pathology and cognitive dysfunction in hyperthermia. The possible mechanisms of nanoparticle-induced exacerbation of brain damage in WBH and its functional significance in relation to our current knowledge are discussed in this review.

Psychotropic drugs use and risk of heat-related hospitalisation.

OBJECTIVE: To assess if use of psychotropic drugs is associated with an increased risk of admission for heat-related pathologies during a heat wave period. METHOD: We conducted a matched case-control study. Cases were defined as subjects admitted to an emergency department for heat-related pathology (hyperthermia or heat stroke) over the August 2003 heat wave. Controls were defined as subjects living in the same area but not hospitalised over the same period and who had at least one prescription form submitted for refunding by the social security insurance in July 2003. Multivariate analyses were used to identify psychotropic drugs independently associated with hospital referral during the heat wave period. RESULTS: Out of the 1405 patients admitted to the emergency department, 56 (4%) presented with heat-related pathology. The mean age of cases was 83 years. Multivariate analyses showed that cases were more likely than controls to be treated with anticholinergic drugs (OR 6.0, 95% CI 1.8-19.6), antipsychotics (OR 4.6, 95% CI 1.9-11.2) or anxiolytics (OR 2.4, 95% CI 1.3-4.4). CONCLUSION: In special risk situations such as heat waves, the risk/benefit ratio of psychotropic drugs which could interfere with body temperature regulation has to be carefully assessed, particularly in the elderly.

Heat intolerance in patients with chronic schizophrenia maintained with antipsychotic drugs.

OBJECTIVE: Schizophrenia may be associated with hyperthermic syndromes such as febrile catatonia, neuroleptic malignant syndrome, and heatstroke. The authors hypothesized that an exercise-heat tolerance test would disclose abnormal thermoregulation in schizophrenic patients. METHOD: Seven male schizophrenic outpatients in remission maintained on depot antipsychotic treatment and eight healthy comparison subjects completed a heat tolerance test that consisted of two 50-minute bouts of walking a motor-driven treadmill at 40xC (relative humidity=40%). RESULTS: A significantly higher rise in rectal and skin temperatures was observed in the patient group. No differences in heart rate, blood pressure, or perspiration were detected. CONCLUSIONS: Schizophrenic patients maintained on antipsychotic drugs exhibit impaired heat tolerance. Possible explanations are a reduced ability to convey heat from the body's core to the periphery with or without excessive heat production. The hyperthermic response to the heat tolerance test may reflect a dysfunction associated with schizophrenia, a neuroleptic-induced side effect, or both.

Heat-related illness: a hot topic in critical care.

With current predictions of climate change, the incidence of heat-related illnesses is projected to increase. Heat-related illnesses occur on a continuum from mild symptoms to fatalities. To prevent heat-related illnesses, nurses should have comprehension of persons at risk. Primary treatment of heat-related illness centers on cooling, but not overcooling, the patient. Heatstroke involves coagulopathies and cytokines, and can result in systemic inflammatory response syndrome and multiple organ dysfunction. Critical care nursing intervention requires more than effective cooling to support bodily processes that have been damaged or destroyed by the pathophysiology of heatstroke.