As summer temperatures climb across much of the country, workers’ compensation stakeholders rightly focus on the familiar hazards of heat: dehydration, heat exhaustion, and heat stroke among employees working outdoors or in hot indoor environments. But there is a less visible risk factor that deserves a place in every claims conversation – one that sits squarely within pharmacy management. Many of the medications injured workers are already taking can quietly undermine the body’s ability to regulate temperature, turning an ordinarily manageable hot day into a genuine safety concern.
For employers, carriers, claims professionals, and nurse case managers, understanding this intersection of pharmacology and heat is not academic. It bears directly on return-to-work (RTW) planning, worksite safety, and the health of the injured workers at the center of every claim.
A Risk That Extends Well Beyond Workers’ Compensation
Although this discussion is framed around workers’ compensation, the underlying risk is not unique to injured workers or claims professionals. Heat advisories are now a near-daily feature of national news each summer, and extreme heat is consistently identified as the deadliest weather-related hazard in the United States, contributing to more than 2,000 deaths annually in recent years amid an accelerating mortality trend (Howard et al., 2024). Any conversation about medications and heat tolerance sits within this larger public health picture, even as this article focuses on its specific implications for claims.
Workers’ compensation adds a layer of complexity that the general population discussion does not usually have to address. A workers’ compensation pharmacy benefit manager (PBM) typically captures only the medications tied to the compensable injury, while an injured worker’s other prescriptions, managed through personal health insurance or a separate PBM, often live outside the claim file entirely. This split can create a partial view: the claim’s medication record may show the muscle relaxant prescribed for the injury but have no visibility into the antihypertensive or antidepressant the worker takes for unrelated health needs, or vice versa. Industry efforts to unify these disparate data streams into a single, holistic medication view have had limited traction to date, which means clinical judgment, provider communication, and direct conversation with the injured worker remain the most reliable ways to bridge that gap.
The aging of the American workforce adds further weight to this issue. Older adults experience age-related declines in sweat gland output, skin blood flow, and cardiovascular reserve that independently reduce heat tolerance, and these physiological changes compound, rather than replace, medication-related risk (Meade et al., 2019). As more workers remain employed into their sixties and beyond, thermoregulatory vulnerability from aging and from medication effects will increasingly overlap within the same claim.
Taken together, these layers, a public health issue playing out one claim at a time, a data gap that no single stakeholder can close alone, and a workforce that is getting older, point to education as the most practical lever available. Content like this is intended to help close that awareness gap, giving claims
professionals, nurse case managers, and prescribers a shared starting point so that medication-related heat risk becomes a routine part of the conversation rather than an overlooked variable.
Why Medications Matter When the Temperature Rises
The human body cools itself primarily through two mechanisms: sweating, which dissipates heat through evaporation, and increased blood flow to the skin, which transfers heat to the surrounding environment. A number of widely prescribed medications interfere with one or both of these processes, or with the brain’s ability to sense and respond to rising temperature.
The Centers for Disease Control and Prevention (CDC) groups these effects into several categories: reduced thirst sensation, interference with central thermoregulation, impaired sweating, and volume depletion or reduced cardiac output that raises the risk of fainting and falls (Centers for Disease Control and Prevention [CDC], 2025). A frequently cited review in the Journal of Clinical Pharmacy and Therapeutics similarly concluded that medicines can accentuate the risk of dehydration and heat-related illness through diuresis and electrolyte imbalance, changed thermoregulation, reduced thirst recognition, reduced sweat production, and hypotension (Westaway et al., 2015).
The Medication Classes Most Relevant to Injured Workers
Several drug classes commonly encountered in workers’ compensation claims are associated with impaired heat tolerance. The degree of risk varies by class, by individual medication, and by patient, and the categories below should be read as a guide to clinical awareness rather than a basis for automatic conclusions about any single prescription.
Opioids. Opioids warrant particular attention in the workers’ compensation context because of their prevalence in pain management. Beyond their effects on thermoregulation, opioids cause sedation and altered cognition that can blunt a worker’s behavioral response to heat—the instinct to move to shade, hydrate, or stop working. Clinical guidance also notes a diagnostic hazard: the symptoms of opioid effects can be confused with, or mask, those of heat stroke, potentially delaying appropriate treatment (Americares & National Association of Community Health Centers, 2024).
Anticholinergic medications. Anticholinergics span a wide range of uses—overactive bladder, allergies, muscle spasm, and Parkinson’s disease, among others—and are among the most consistently implicated in heat-related risk. By blocking the muscarinic receptors that help activate sweat glands, they can reduce sweating and impair the body’s primary cooling mechanism (CDC, 2025; Westaway et al., 2015). A systematic review and meta-analysis found that agents with strong anticholinergic activity were among the classes with the most consistent evidence for impairing thermoregulation during heat stress (Hospers et al., 2024).
Diuretics and certain cardiovascular medications. Diuretics promote fluid loss, which can compound the dehydration that heat and sweating already cause. Their risk appears especially elevated when combined with an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor blocker (ARB) (Westaway et al., 2015). Non-selective beta-blockers may also blunt the cardiovascular response that redirects blood flow to the skin for cooling (Hospers et al., 2024).
Psychotropic medications. Antipsychotics can interfere with central thermoregulation in the hypothalamus and impair sweating, particularly agents with additional anticholinergic activity (CDC, 2025). Antidepressants show a more mixed picture: selective serotonin reuptake inhibitors (SSRIs) may increase sweating and dehydration risk, while tricyclic antidepressants (TCAs) may decrease sweating (CDC, 2025). Given how frequently depression and anxiety accompany prolonged workers’ compensation claims, these medications are a common feature of the injured-worker medication profile.
Stimulants. Stimulants can raise the body’s metabolic rate and heat production, interfere with central thermoregulation, and alter heat perception (CDC, 2025).
An Honest Word About the Evidence
It is worth being candid about the state of the science. Much of the foundational research on medications and thermoregulation is drawn from epidemiological studies of major heat events and from controlled trials conducted largely in healthy young men over short exposures. A 2024 meta-analysis found strong evidence for impaired thermoregulation with strong anticholinergics, non-selective beta-blockers, and anti-Parkinson’s agents, but did not find that every medication commonly flagged in public-health lists measurably altered core temperature under study conditions (Hospers et al., 2024). The biological mechanisms are well established, and the epidemiological signal for psychiatric and cardiovascular medications and high anticholinergic burden is real. But the risk is a function of the specific drug, dose, the individual, and the environment—not a blanket property of every medication on a list. That nuance is exactly why individualized clinical review, rather than reflexive assumption, is the right posture.
What This Means for Workers’ Compensation Stakeholders
The practical implication is that an injured worker’s medication regimen is a variable worth considering when heat enters the picture—particularly for those returning to physically demanding roles, outdoor work, or hot indoor settings such as warehouses, foundries, and kitchens. Several considerations follow:
- Include medication-related heat risk in RTW planning. A worker cleared for modified duty may still face elevated heat risk if their regimen affects thermoregulation. Coordinating RTW planning with an awareness of medication effects can inform decisions about shift timing, hydration breaks, and task assignment during peak-heat periods.
- Watch for additive risk in polypharmacy. Risk is not simply the sum of individual medications. Multiple agents with anticholinergic activity, or a diuretic combined with an ACE inhibitor or ARB, may carry greater risk than any single drug alone (Westaway et al., 2015). Injured workers on complex regimens—a pattern already familiar in catastrophic and long-tail claims—deserve particular attention.
- Recognize the signs of heat-related illness. Confusion, dizziness, unusual fatigue, and changes in sweating can signal heat stress, and may be easy to misattribute when a worker is already managing an injury and its treatment.
- Support communication among the care team. Prescribers, treating providers, and the injured worker may not always connect the dots between a routine prescription and a hot work environment. A pharmacy benefit manager can help surface these considerations for the claim team.
The Role of Thoughtful Pharmacy Management
This is where a proactive, pharmacy-focused, relationship-driven approach adds value. At Preferred Medical, our role is not to make treatment decisions for prescribers or claims professionals, but to give them the clinical information they need to make well-informed ones. Reviewing an injured worker’s regimen with an eye toward heat sensitivity is a natural extension of the utilization management and clinical review work that supports every claim year-round.
The goal is not to discourage appropriate medication use. The medications discussed here treat real conditions and serve genuine purposes in an injured worker’s recovery. Rather, the aim is awareness: recognizing that pharmacology and environment interact, that the interaction can affect both safety and recovery, and that a proactive conversation before a heat wave is far preferable to managing a heat-related incident after the fact.
As with so much in workers’ compensation, the difference between a routine summer and a complicated one often comes down to the questions we think to ask early. When temperatures rise, reviewing an injured worker’s medication should become part of every return-to-work conversation.
References
Americares, & National Association of Community Health Centers. (2024). Medications and heat: Guidance for providers. Americares. https://www.americares.org
Centers for Disease Control and Prevention. (2025). Heat and medications – Guidance for clinicians. U.S. Department of Health and Human Services. https://www.cdc.gov/heat-health/hcp/clinical-guidance/heat-and-medications-guidance-for-clinicians.html
Hospers, L., Dillon, G. A., McLachlan, A. J., Alexander, L. M., Kenney, W. L., Capon, A., Ebi, K. L., Ashworth, E., Jay, O., & Mavros, Y. (2024). The effect of prescription and over-the-counter medications on core temperature in adults during heat stress: A systematic review and meta-analysis. eClinicalMedicine, 77, Article 102886. https://doi.org/10.1016/j.eclinm.2024.102886
Howard, J. T., Androne, N., Alcover, K. C., & Santos-Lozada, A. R. (2024). Trends of heat-related deaths in the US, 1999–2023. JAMA, 332(14), 1203–1204. https://doi.org/10.1001/jama.2024.16386
Meade, R. D., Notley, S. R., & Kenny, G. P. (2019). Aging and human heat dissipation during exercise-heat stress: An update and future directions. Current Opinion in Physiology, 10, 219–225. https://doi.org/10.1016/j.cophys.2019.06.001
Westaway, K., Frank, O., Husband, A., McClure, A., Shute, R., Edwards, S., Curtis, J., & Rowett, D. (2015). Medicines can affect thermoregulation and accentuate the risk of dehydration and heat-related illness during hot weather. Journal of Clinical Pharmacy and Therapeutics, 40(4), 363–367. https://doi.org/10.1111/jcpt.12294
Note: This article is intended to provide general clinical information for workers’ compensation professionals and does not constitute medical advice. Medication decisions should always be made by qualified prescribers in consultation with the individual patient.