Pharmaceuticals in the environment
Medicines harm the environment beyond their greenhouse gas emissions. Drug residues leak into ecosystems from human and veterinary use and from manufacturing, and come back to harm people; packaging adds waste, and the drugs themselves draw on a biodiversity that is being lost. Pharmaceutical waste arises in the clinic, the home and the factory, and its burden can be reduced by disposal, regulation, education and an environmental extension of pharmacovigilance.
The environmental impacts of medicines
The healthcare industry's environmental impacts reach far beyond climate change alone. The environmental impacts of pharmaceuticals that have been explored include greenhouse gas emissions, pharmaceuticals in the environment, and packaging waste. Pharmaceuticals contaminating the environment is a well-known, multidimensional problem, and biologically active pharmaceuticals and their metabolites can have off-target effects when they enter the environment.
Over time, little attention has been paid to the environmental impact of pharmaceuticals. As of 2023 very few studies had estimated their burden on the environment, all of them in a few countries and often with non-standardised methods that made comparison difficult. There is an urgent need to measure the impact of unintended environmental exposure to pharmaceuticals and to understand the current picture of the problem. Awareness must be raised among the different stakeholders through education and training.
How drug residues reach ecosystems and return to people
Pharmaceuticals in the environment refers to the leakage of pharmaceutical residues into environmental sources. Pharmaceuticals are used in human healthcare, prescribed in hospitals and taken over the counter, and in veterinary care for livestock, aquaculture and agriculture. By various means they leak into the environment, either through wastewater or by being sprinkled directly into water and onto crops. In ecosystems the residues have a range of effects on fish, such as feminisation, cause genetic mutations in animals, and alter the neurology, reproduction, growth and development of different species. They also harm people, and the emergence of antimicrobial resistance is one prominent example.
Pharmaceuticals, as a unique form of healthcare waste, are released into the environment with implications for human health, including antimicrobial resistance. By 2021, more than 600 active pharmaceutical substances, or their metabolites and transformation products, had been detected worldwide in all sorts of environmental matrices, mainly antibiotics, analgesics, lipid-lowering drugs, beta-blockers, X-ray contrast media and synthetic oestrogens. Earlier reviews, mostly from high-income countries, showed pharmaceuticals in water bodies. But one of the most extensive studies, of medications in 1,052 rivers across 104 countries, found the most contaminated rivers in the low-middle-income countries of sub-Saharan Africa, South Asia and South America. As demand for pharmaceuticals grows around the world, the industry's impact on the environment will be amplified. Drug use in humans and animals is ever increasing, and one study projects that global consumption of veterinary antimicrobials will exceed 100,000 tons by 2030.
The environmental impact of pharmaceuticals is a global problem, and because of where the drugs are produced it has large effects in other parts of the world, with India and China in particular taking a large hit from pharmaceutical production. Wastewater from pharmaceutical manufacturing sites ends up in the environment, and huge quantities of pharmaceuticals have been found in the wastewater and environmental systems of these countries, so the environmental impact is outsourced too.
Vultures in South East Asia show how an impact on the environment comes back to human health. The vultures fed on the carcasses of treated cattle, given diclofenac in one account and antibiotics in another, and developed deadly kidney disease. On one account the drug wiped out about 95% of that vulture population, and other species such as feral dogs increased in number and spread disease. The downstream effects caused the deaths of half a million people, more than half a million on that account. The case is a reminder that pharmaceutical products can have unforeseen ecological consequences.
What pharmaceutical waste is and where it arises
Pharmaceutical waste is not something people think about in their day-to-day routine, yet thousands of metric tons of it are produced each year, which may be harming both humans and the environment. The WHO defines pharmaceutical waste as expired, unused, spilled and contaminated pharmaceutical products, prescribed and proprietary drugs, vaccines and sera that are no longer required and that, because of their chemical or biological nature, need to be disposed of carefully. A pharmacist defines it as any drug product no longer used for its intended purpose: a medication may be waste because it is expired, discontinued or damaged, and drug waste also includes vials, syringes and even materials such as the tubing used to give chemotherapy, in solid, liquid or gas form.
According to the UK's National Health Service, pharmaceutical waste in the healthcare setting can arise from:
- Non-compliance: patients do not take medicines as prescribed, for example at irregular intervals or in incorrect doses, leaving unused drugs that are eventually discarded.
- Intentional non-adherence: patients stop taking medication because of adverse events or personal beliefs.
- Unintentional non-adherence: patients forget and stop taking medicines, or fail to take them at the correct intervals.
- Non-preventable waste: patients die and their medications remain unused, or a change in treatment means the medicines already dispensed are no longer required.
- Preventable waste: patients stockpile medicines "just in case", and all items from repeat prescriptions are dispensed even if the patient no longer takes them.
Other sources include improperly disposed medications, effluents from pharmaceutical manufacturing plants, excretion of metabolites by patients and the irrational use of medications in agriculture. A single hospital can produce a great deal of drug waste, but a lot of it arises at the manufacturing companies. By one pharmacist's estimate, a large pharmaceutical company can produce 80,000 to 100,000 metric tons of solid drug waste per manufacturing plant per year, about the weight of 50,000 cars. On the same estimate, each plant also produces on average 15 million cubic metres of wastewater a year, roughly 4,000 Olympic-sized swimming pools, from water used for purposes such as processing or cooling that becomes contaminated with drug waste.
Like any other waste, pharmaceutical waste ends up in the environment. Viewpoints conflict on whether it poses a serious threat to the environment, but some research suggests that it does. The disposal of inhaler propellants may be contributing to damage to the ozone layer, the hormones in oral contraceptives may be affecting aquatic organisms such as fish when released into water, and drug waste could play a role in the rise of antibiotic-resistant organisms. Drug waste can also harm humans, and when drugs are accidentally ingested or purposely misused the consequences can be fatal.
Disposing of medicines safely
In 2023 the safe disposal of medicines was a current issue, but awareness among healthcare professionals and consumers was low. In the United States there are federal regulations on how to dispose of, recycle or return drugs, yet in 2018 many people were unaware of them. To reduce the chance that someone accidentally ingests or purposely misuses discarded medications, a pharmacist advises consumers to consider these options:
- Take the drugs to authorised collectors, such as pharmacies, hospitals and local law enforcement.
- Take part in a medicine take-back programme, a good way to dispose of or recycle most public and household medications.
- At home, seal the medication in a plastic bag with coffee grounds, cat litter or any substance that makes it unappealing, so that people or animals do not open the bag and consume it, and put it in the trash.
- Remove all personal information from prescription labels before recycling or discarding the containers.
- Avoid flushing medications unless the FDA specifically recommends that method.
- When unsure, contact the local waste management authority for its disposal guidelines.
Manufacturers sometimes include information on the safe disposal of expired medications in the summary of product characteristics and the patient information leaflet, but consumers do not always follow it. Clear disposal guidelines from manufacturers in these documents, strictly followed by end users, can help decrease the environmental load of medicines. Some authors argue that the burden of responsible disposal should be shared between government, patients and pharmaceutical companies. Proper patient counselling on safe medication disposal can significantly affect this public health challenge, and a practical approach would be to prioritise the issue in the training curricula of all healthcare workers. Cost-effective and acceptable government-run collection and disposal systems are a long-term solution.
Packaging waste
Packaging waste is a popular topic, partly because it is so visible. Drugs come packaged in plastic, aluminium and paper, are wrapped in more plastic and shipped around the world, and carry leaflets inside that are usually not read and are thrown away. The waste is usually disposed of as general waste and ends up in landfill or is incinerated. By 2024 more and more health systems were implementing take-back programmes to sort it, recycle what they can and incinerate the rest. There is very little data on how much packaging waste is produced, which leaves a gap in what is known of its impact.
Biodiversity
In the view of one researcher of the pharmaceutical supply chain, biodiversity often gets left out of conversations about environmental impact, and her struggle to find research on it shows how large the gaps are. Pharmaceuticals are often derived from nature, which supplies either the inspiration for a drug or the drug itself, directly or as a synthetic analogue. Estimates of how much is derived from nature vary: some say 25%, some 50%, and one article puts it at about 75% of the drugs in use. Drug development increasingly looks to unresearched areas of nature, and one recent news article reports thousands of microorganisms in the ocean left to explore as potential drug sources. Some drugs come directly from animals, such as exenatide, from the saliva of Gila monsters. The same researcher is not sure that thought is being given to how this affects biodiversity, both through the use of animals and nature to manufacture drugs and through the loss of biodiversity elsewhere, with the potential loss of inspiration for future pharmaceutical products, and she sees this as a key connection that is under-addressed.
Policy and regulation
The presence of pharmaceuticals and their active metabolites in the environment is a cause for great concern, and a concerted multidisciplinary approach is needed to tackle it. The UN Environment Programme has identified environmentally persistent pharmaceutical products as a serious problem requiring urgent policy remedies. By 2023 some regions, companies and countries, among them Bhutan, Canada, Colombia, Ghana, India, Israel, Liberia, Lithuania, Sri Lanka, the European Union and the United States, had enacted measures to reduce the environmental impact of pharmaceuticals, while other countries have inadequate or non-existent guidelines and regulations. In 2018, pharmaceutical companies were striving to recycle, recover and reduce the sources of waste and to integrate green chemistry into manufacturing, and the public was taking part in programmes that recycle drugs and raise awareness of drug waste.
Manufacturers and regulatory authorities need to work together on a framework for the environmental risk assessment of medications and for establishing and evaluating risk minimisation activities. This multidisciplinary approach requires governments, non-governmental organisations, physicians, pharmacists, patients and the public to work together to reduce the burden of pharmaceuticals on the environment. Strict regulations, passed and implemented urgently, still offer the hope of reversing or preventing further impact on the environment and the food chain.
Extending pharmacovigilance to the environment
The incorrect disposal of pharmaceutical waste is a well-known issue of environmental risk and sustainability, but in one pharmacovigilance editor's view very few in the field have ever regarded it as a potential area for synergy and risk minimisation from a pharmacovigilance perspective. Pharmacovigilance professionals can be at the forefront and create a movement, since they are in a unique position to educate all relevant stakeholders about safe medicine use and disposal.
Pharmacovigilance comprises routine activities and an expanding scope of activities beyond the regular reporting of adverse drug reactions, and the EMA's good pharmacovigilance practice guidelines recommend additional activities to identify delayed safety concerns. Low environmental concentrations, defined by the US FDA as below one part per billion, are assumed to pose only acceptable risks, but an acceptable risk is still a risk. The environmental impacts of pharmaceuticals are often so slow and inconspicuous that they go unnoticed until very late. Ecopharmacovigilance, pharmacovigilance activity dealing specifically with the effects of medicines on the environment, could very well be proposed as an additional risk minimisation activity. Some authors have proposed targeted implementation focused on monitoring the occurrence of high-priority pharmaceuticals in environmental samples, managing primary emission sources, legislation and research on high-priority pharmaceutical pollutants, and targeted educational strategies for specific vital populations.
To the authors of one 2023 review of ecopharmacovigilance, the ongoing success of pharmacovigilance programmes in various countries suggests that pharmacovigilance is best positioned to take on activities dealing with environmental effects. Ecopharmacovigilance can be easily incorporated within the routine activities of existing programmes in close collaboration with manufacturers and regulatory agencies. Spontaneous reporting, intensive monitoring and database studies have been proposed as starting points for ecopharmacovigilance, and can be implemented for the continued environmental risk assessment of approved products. Some researchers identify education and training in ecopharmacovigilance and environmentally conscious prescribing as essential components that could significantly affect how medicines are used and disposed of. Countries with non-existent or inadequate environmental regulations can learn from the EMA and the US FDA. The same authors hold that the scope of pharmacovigilance must be extended to include ecopharmacovigilance, and that pharmacovigilance professionals can easily contribute their skills to it.