The Environmental Side Effects of Medications: Reducing the Carbon Footprint of Psychiatry

Journal of Psychiatry Reform Vol 9, #12, July 2022


Ana Hategan, M.D.1,✉,iD, Myles Sergeant, P.Eng., M.D.2, James A. Bourgeois, O.D., M.D.3


Author Information

1  Clinical Professor, Geriatric Psychiatrist, Division of Geriatric Psychiatry, Department of Psychiatry and Behavioural Neurosciences, Michael G. DeGroote School of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada. ✉ [email protected]. iD:

2  Assistant Clinical Professor, Family Physician, Department of Family Medicine, Michael G. DeGroote School of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada. [email protected].

3  Clinical Professor, Consultation-Liaison Psychiatrist, Chair, Department of Psychiatry, Baylor Scott & White Health, Central Texas Division; College of Medicine, Texas A&M University Health Science Center, Temple, TX, USA.  [email protected].



Physicians are encouraged to actively consider the environmental impact of medical interventions. Chief among these considerations is the environmental burden of medication development, production, and disposition. Addressing the environmental consequences of medication prescribing is a critical part of mitigating carbon emissions in healthcare. This matter is often neglected, when compared to the problem of disposition of medical waste. Unquestionably, psychotropics save lives and improve patient function. Yet, they also contribute to a significant environmental footprint. The authors herein call for an embrace of a collective responsibility of physicians and other mental healthcare professionals, medical institutions, and the pharmaceutical industry to address the environmental health crisis. There is urgency for collective action needed to secure an ongoing livable human climate.  It is herein suggested that labelling psychotropics, and by inference all medications, with a “climate-score” to include their carbon footprint may help achieve a more sustainable and environmentally friendly psychiatric practice.


Raising Awareness about Carbon Emissions from Medications

Recent research assessing carbon emissions reported by large pharmaceutical companies has found that this industry emitted more, and was more carbon-intensive, than the automotive sector [1]. Consequently, greater consciousness of the impact that healthcare systems can play in reducing the significant environmental impact of medications is imperative. The point at issue is regarding what can be done in unison for the carbon reduction of pharmaceuticals at the level of healthcare providers (e.g., clinicians, pharmacists), patients/consumers, hospital leaders/administrators, and pharmaceutical industries.

As physicians, we need to know what this specific medication’s environmental impact is compared to other acceptable alternatives. For this informed choice, long-awaited, transparent, and publicly available data on the overall impact of pharmaceuticals is needed. This concern can be expressed at many levels, including the environmental consequence of the industrial production, packaging, distribution, usage, and impact of disposition of unused medications. Several pragmatic potential actions to mitigate those are described below.

Notably, pharmaceuticals have emerged as a new class of environmental contaminant, an area where we certainly could do better. Pharmaceuticals are present in almost all the world’s rivers, and pharmaceutical pollution is increasingly recognized as a major threat to aquatic ecosystems [2]. It is regrettable that studies have shown that psychotropic medications, while illness-treating and lifesaving, are no exception in their environmental impact [3]. These pharmaceuticals may be poorly eliminated by wastewater treatment plants, resulting in many of them remaining present at meaningful concentrations in surface waters (i.e., any body of water above ground, including the oceans) [3]. For example, the drug oxazepam, a benzodiazepine anxiolytic, has been frequently detected in rivers, and poses a threat to environmental and/or human health in more than a quarter of the studied locations globally [3, 4]. As such, some have called for more stringent regulations and “greener” technologies to be implemented for waste release from industrial and hospital point sources regarding pharmaceutical development, manufacture, and use [2].

Implications for Psychiatry and Healthcare Systems

Clinicians could consider reducing unnecessary polypharmacy, which could have the beneficial “side effect” of being good for the environment; e.g., in psychiatric practice, mirtazapine monotherapy for major depressive disorder could be considered in lieu combination therapy of sertraline plus bupropion plus trazodone. In a recent review aimed to reduce overprescribing in the UK, and thus to reduce carbon emissions, at least 10% of the total number of prescription medications in primary care were judged as “unnecessary” [5]. Therefore, physicians should consistently apply medication optimization, which is a useful and practical guideline seeking to ensure that medications provide the greatest possible benefit to patients by encouraging medication reconciliation and medication review, including deprescribing, to reduce the overall number of prescribed medications and ultimately minimize environmental impacts and harms [5]. Although reducing overprescribing does not mean reducing treatment effectiveness, it can have many benefits not only for patients, but for the environment as well. For example, reducing polypharmacy in some older patients with hypertension was not associated with substantial change in systolic blood pressure control at 12 weeks when compared with usual care [6].

Furthermore, there is the issue of drug expiration dates. One study showed that all the expired medicines tested were still pharmacologically active beyond their recommended expiration dates, even when not stored in temperature-controlled conditions [7]. This raises the question of how much the disposal of prematurely “expired” medications contribute to unnecessary waste and carbon footprint. This area of how expiration dates are determined requires further careful examination.

There is also the issue of patient treatment compliance that may also contribute to carbon footprint. The US Centers for Disease Control and Prevention showed that once prescription medications are acquired by patients, half of all prescriptions are not taken as directed and many are presumably discarded, with inevitable environmental impact [8]. This has the potential to create vast amounts of waste. Packets of medications returned unopened may not be reused for other patients under the policies of current North American medical regulatory agencies. Subsequently, there will be environmental costs from production and distribution of these medications as well as risks associated with improper disposal.

Healthcare organizations can commit to environmental stewardship strategies, and “anchor” institutions, including hospitals and medical centers, could play a vital role in leading by example. Undertaking this challenge will require ambitious collaboration among the healthcare, pharmaceutical, and environmental services sectors. It is likely that stakeholders may have ways that can be leveraged to advance sustainable procurement in medicine. What is measured can potentially be managed and, as such, measurement of carbon footprint impact could be the entry point for procurement agencies that engage with suppliers to understand and quantify their environmental impact. This may steer the pharmaceutical industry to be more sustainable, such as giving all these companies a “green rating score” based on environmental footprint for medication development and production, while expecting the procurement sector (beyond purchasing of pharmaceuticals) to add “sustainability” to their overall scoring system, either of individual items or scoring the entire company. This could then drive the needed market transformation towards a decarbonized economy.

Pharmaceutical companies are required to perform an environmental toxicity assessment for new drug applications, but imported active pharmaceutical ingredients used in a medication’s ultimate production are not yet a requirement to include in assessments [1]. Although some pharmaceutical companies have started to voluntarily report carbon impact data in response to market pressures [1], the regulatory agencies may need to standardize the requirement of all pharmaceutical companies to make the public information on the carbon footprint of each medicine in a clear, practical fashion, perhaps with consumer-friendly “traffic light” styled rating system (RAG): red (high), amber (medium), and green (low) labels to suggest environmental impact, similarly to food-related consumers’ behavior. This may stimulate clinicians to emphasize usage of locally produced medicines, when available, to minimize transit costs, among other considerations.  Table 1 outlines a concept for a necessary climate-score of medicines to assist physicians; if they are choosing between two clinically similar products, such a rating scale might help to inform them.

Healthcare systems could also add the environmental impact of medicines in the electronic medical record (EMR) files. Incorporating this data into the EMR may help physicians readily compare medication options in real time while assessing patients in their respective medical settings. Such endeavors may be impactful on making people think of their actions differently. Pharmacists could make a “comparative environmental impact of antidepressants” table to guide physicians and other prescribers in regard to climate-scores based on greenhouse gas emissions.  “Carbon literacy” training modules that support clinicians and other staff members to make a meaningful action plan for carbon footprint reduction of medicines may need to be offered by institutions.

Future Practice Points

Labelling medicines with information about their carbon footprint could eventually help cut emissions by modifying their use to only when most necessary and in limited quantities. Labelling medicines may push forward the involvement of the pharmaceutical sector to perform an independently validated methodology to assess the environmental impact of pharmaceuticals. Where more than one suitable medication option is available for the patient, prescribers may appreciate clear and helpful guidance on which of the options will be less damaging to the environment. It would be necessary to work with information technology providers to ensure that this data is routinely incorporated into all EMR systems, and beyond, such as mobile medical reference apps, point-of-care evidence based clinical resources, and digital textbooks.

Table 1. A concept for a climate-score of medicines using an environmental  impact and carbon footprint type of scoring to help physicians when choosing between clinically similar products.

RAG system/ Labelling of medicines

Environmental impact score*

Carbon footprint score**



1  =========> 100
Environmental Outcomes


++ / +++



Note: *Environmental impact (calculated in kg CO2-equivalent).  The carbon component of the label may use energy requirement as an indicator of environmental impacts of medicines; however, the authors recognize that the full environmental impact of medications is much broader than energy use alone (e.g., such score may need to include medication half-lives and cost). **A carbon footprint may be developed by scoring each pharmaceutical across 5 categories of impacts: (1) industrial system (development and production), (2) degree of disposition (impact of environmental contamination, impact of unused or expired medications), (3) distribution and transport, (4) packaging, and (5) length of the supply chain. The carbon footprint can use a score between 1 and 100, where a lower score indicates poor environmental outcomes (more carbon emission) and a higher score indicates better environmental outcomes (less carbon emissions). RAG; Red, Amber, Green.


Statements and Declarations:

Funding: None.

Conflict of Interest: Dr. Hategan and Dr. Bourgeois report no conflicts of interest concerning the subject matter of this article.  Dr. Sergeant is a co-founder of the PEACH Health Ontario initiative, a network of clinicians and administrators to support climate action across Ontario, Canada.



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