Influence of drug use on morbidity and mortality in heatstroke

Numerous medications and illicit drugs can predispose an individual to heat illness, primarily by altering thermoregulation by either increasing endogenous heat production or impairing heat dissipation. This study sought to determine if use of such drugs was associated with more severe illness in patients presenting with heatstroke. A case control study was conducted on adult patients (age, ≥14 years) admitted to an intensive care unit with an admitting diagnosis of heatstroke at two academic teaching hospitals in Phoenix, AZ, between 31 August 2005 through 31 July 2010. Subjects were classified as "users" if they admitted to taking a drug on a pre-defined list of drugs associated with abnormal thermal homeostasis, or if a urine test for drugs of abuse revealed the presence of an amphetamine or cocaine. Similarly, subjects who did not take such drugs were considered "non-users." Seventy-eight patients were identified, with complete medication histories available for 74 of 78 subjects. The overall prevalence of drug utilization was 41.9 % (31 of 74). The median length of stay was 3.0 days for the non-users compared with 9.0 days for "users." There was no difference between users and non-users with regard to mortality. Drugs that impair thermoregulation are frequently encountered in patients admitted for heatstroke. Patients taking such drugs may experience increased morbidity over those patients not taking such drugs.