The potential impact of climate change on medication access and quality deserves far more attention

Abstract

Notwithstanding the obvious interconnection between humans and the world that they share with non-human inhabitants, the impact of our changing climate on certain aspects of the public health ecosystem has been under-investigated. We briefly describe some of the possible climate-induced changes in the procurement, distribution, access and use of medications, including those for animals generally and livestock specifically. A fuller understanding of the effect of climate change on medicine supply, access, use and quality, including how these affect antimicrobial resistance, would contribute to the further development of the “One Health” and “One Health Systems” concepts. We suggest that this understanding is not yet available, even though the changing incidence of infectious diseases due to changing climate has been studied. There is a need for improved understanding of the impact of extremes of humidity and heat on medication quality and research into heat-stable medicines as well as strategies for the improving resilience of the pharmaceutical supply and distribution system in complex public health emergencies caused by aberrant weather patterns.

Climate change is leading to increased frequency and intensity of environmental disruptions, such as wildfires, excessive rainfall leading to floods, and droughts, which are all modifying disease patterns in both high-income and low- to middle-income countries (LMICs). In the United States alone, more than $820 billion in health damages accrue annually from burning fossil fuels and climate change-related events [1]. Increased flooding and storm runoff disseminates pathogens leading to various waterborne diseases [2], and, in LMICs, prolonged flooding is associated with increased risk of diarrhea among children [3]. A recent review of over 7000 climate-related disasters since 1978 found that hydrological disasters were the most frequent and deadliest of climate-related events [4].

Heavy rain and flooding harm respiratory function via flood water contamination and mold growth [5] that can trigger allergic reactions, cause exacerbations of reactive airway disease or chronic obstructive pulmonary disease, and lead to fungal infections in vulnerable populations. Moreover, it seems clear that as temperatures increase, there is an increasing emergence and re-emergence of certain parasitic and infectious diseases, some of which are already proliferating, that will accelerate the use of drugs now used only on a limited basis in the Northern Hemisphere [6].

Climate change affects not only disease burden but also all aspects of medication supply and access functions. The medical treatment chain requires full access to, among other things, pharmaceuticals, infusions, and blood products, all of which could be adversely influenced by climate change. What might be the effect of climate change on the procurement, distribution, access and use of medications? At this point, we simply do not really know in a way that can make a difference.

1. Impact on medicine supply chains

Flooding, devastation from severe weather events, and wildfires can potentially impact the supply chain of medications as they may cause disruption of production, transportation, inventory, and sales [7]. Supplies of natural product-based raw materials, such as artemisinin from Artemisia annua L., diterpenoids from the Pacific yew Taxus sp. used in paclitaxel synthesis [8], could potentially be impacted due to the lack of availability and quality of natural materials, resulting from diminishing water supply and excessive temperature. For example, prolonged drought causes water stress in forest trees, making them more susceptible to infection by pathogens [9]. Extreme weather events could disrupt delivery systems, resulting in delays as well as increased transportation costs [7].

This is not an easy problem to fix as it is likely multi-dimensional. For instance, almost immediately after Hurricane Maria hit Puerto Rico in 2018, the shortage of small-volume saline bags (250 ml or less) made by Baxter became acute [9]. Baxter had no redundancy in manufacturing capacity for these products and the other saline suppliers could not make up the shortage [10].

This issue has risen to the highest levels of global public health, at least for some. Recently, UNITAID, the initiative responsible for helping improve access to major diseases in LMICs, has recently said that it would promote practices and products “… that make the provision of healthcare more sustainable. We will work to reduce the impact on the climate and on the environment of product manufacturing and supply” [11]. We need more information on the impacts of climate change on the production, inventory and supply of biomedical products so that we can identify vulnerable areas and build a climate-resilient system.

2. Impact on use and quality of medicines

The altered use of pharmaceuticals driven by climate change has been primarily inferred from the projected incidence of both communicable and non-communicable diseases under various climate change scenarios. Redshaw et al. [6] inferred that climate change will be associated with altered patterns of pharmaceutical use, notably the use of chronic disease medications such as beta-blockers, angiotensin converting enzyme inhibitors, statins, salicylates, antiplatelets, vasodilators, anticoagulants among others.

Moreover, vaccines, insulin, and blood products are heat-susceptible and may degrade due to rising temperatures, especially in settings with limited access to cold chain or when electrical power is cut due to extreme weather events. Such degradation can lead to safety issues if high temperature or humidity compromise the efficacy and quality of these medications [12].

For example, post-partum hemorrhage – severe bleeding after childbirth – is a leading cause of maternal deaths, especially in LMICs. Oxytocin, the standard medication used to prevent and treat post-partum hemorrhage, requires cold storage, which many low-resource settings lack. UNITAID is investing in heat-stable carbetocin, an alternative product that can be used in areas where the quality of oxytocin cannot be guaranteed due to insufficient or unreliable cold chain systems, making it both a critical health intervention and more resilient to climate change [11]. In contrast, insulin is also not heat-stable but for those requiring it for survival, there are no alternative medicines.

Many medicines can potentially have their therapeutic effects enhanced during heatwaves and cause serious health issues, even if used appropriately. For example, Šklebar, et al. [13] reported that use of percutaneous nitroglycerin “… could lead to an additional decrease in blood pressure in warm weather…” and, similarly, that “…subdermally injected insulin could create a severe hypoglycemia in diabetic patients.”

Thus, the impact of warming temperature on the use and quality of medicines presents significant challenges, emphasizing the need for innovative solutions and resilient healthcare systems to ensure the safety and effectiveness of medications.

3. Impact on antimicrobial resistance

Climate change is already contributing to the increased use of antimicrobials in both humans and animals, as rising temperature and extreme weather events have been leading to more spread of infectious diseases. Although unable to infer causality, Macfadden et al. [14] found that a 10 °C difference in average temperature across regions of the US was associated with increases in antibiotic resistance of 4.2 % for Escherichia coli, 2.2 % for Klebsiella pneumoniae, and 2.7 % for Staphylococcus aureus after adjusting for mean minimum temperature (°C), antibiotic class-specific prescription rate, inpatient or outpatient-derived isolates, presence of laboratory standard, and population density. As noted, rising temperature and altered humidity will have an effect on environmental degradation of medicines. In principle, the use of antimicrobials with sub-therapeutic levels of active pharmaceutical ingredient could result in the necessary selection pressure for resistance to develop. For example, drug-resistant mutant subpopulations that already exist in a patient would be expected to be enriched and amplified when antimicrobial concentrations fall within a specific range (the mutant selection window) [15]. Because poor quality medicines often deliver subtherapeutic doses of an active ingredient, the link between environmentally-caused poor quality medicines and the development and spread of resistance would appear to have a solid, intuitive basis. We know little about this and observational field studies to investigate this would be difficult to undertake.

4. Impact on animal/veterinary medicines

In keeping with this One Health analysis, we have some brief reflections on the impact of climate change on veterinary sciences with respect to medicines. As one example, the impact of changing climate on medicine residues in food is primarily a question of how climate change will affect diseases of farm animals. Several published reviews of climate change suggest that, although data is limited, use of veterinary medicines is likely to increase in the coming decades [16] Use of medicines in animal health generally, and use in dealing with zoonotic diseases specifically, will be impacted by our changing climate. Moreover, topics discussed in previous sections, such as the impact on the use and quality of medicines and antimicrobial resistance, are also relevant to veterinary medicine. The effect which climate change may have on such medicines is poorly understood but surely environmentally-degraded ecosystems lead to unhealthy humans and animals. [17]

The world's climate and its ecosystems are rapidly changing. The impact of this change on medication access and quality are potentially serious challenges and have not received sufficient attention in our opinion. The interactions between climate change and supply, distribution and access to pharmaceuticals are important to investigate, not just for their intrinsic academic interest, but to quantify the resulting public health and economic implications on all levels of healthcare. Moreover, these challenges are likely to be greater in LMICs.

There is a need for improved understanding of the impact of extremes of humidity and heat on medication quality and research into heat-stable medicines as well as strategies for the improving resilience of the pharmaceutical supply and distribution system in complex public health emergencies caused by aberrant weather patterns.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Authorship contribution statement

Warren A. Kaplan: Writing – original draft, Investigation. Davidson H. Hamer: Writing – review & editing, Investigation. Kayoko Shioda: Writing – review & editing, Investigation.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability

No data was used for the research described in the article.