From Volume 48, Issue 11, December 2021 | Pages 926-930
Increasingly, healthcare practitioners need to be concerned not only with the type and dose of the medication prescribed to dental patients, but also to how waste is managed. This article discusses the results of a literature review on the harm both to the environment and population health caused by pharmaceutical waste and looks at potential ways of mitigating this worldwide problem.
Dental professionals have a duty to do no harm, but there is a lack of consideration by the dental team given to the harm caused by pharmaceutical waste (PW) and related poor waste management practices. Dentists prescribe a considerable amount of medication. From 2017 to 2020 for example, dentists in England prescribed 13,235,561 items, with dentists responsible for prescribing 10% of antimicrobials.1,2,3,4
There has been no calculation of how much waste occurs within dental prescribing. Within broader healthcare, the pharmaceutical industry produced $900 billion in prescription medicines globally. Within England, the NHS alone reports that annual management of pharmaceutical waste costs £300 million annually.1,2 An estimated 1.27 million kg of prescription medications are left unused by consumers in the US annually.3
Several studies show traces of this waste found in global ecosystems, either by direct poor disposal methods or from the metabolites of the drugs through waste water.4 This leads to bacterial resistance to antibiotics, altered genes and reproductive organs in fish, as well as contaminated drinking water.1
Several reasons account for the creation of PW. Premature cessation of taking medication owing to an improvement in symptoms is one of the most commonly cited.6 Death of a patient can also result in significant production of waste medication, accounting for up to 20% of the problem.7 Expiration of drugs accounted for between 1% and 50% of pharmaceutical waste.5,8 Developing adverse effects of medications will lead to patients prematurely stopping medication.9 Prescribing practices by physicians have also been cited as a contributing factor to increased PW, as well as changes to medication when a patient has only partially completed a lengthy prescription.2
The most common method of disposing of PW is via household waste. The literature showed that between approximately 25% and 79% of people used this means, and disposal by sink (Figure 1) or toilet is as high as 50%.5,8 Returning unused medication to pharmacists is less popular, accounting for less than 30% of the participants in the studies examined.10 Giving unused medications to a family member or friend for use has been listed as another means of disposal and, while not necessarily of harm to the environment, poses a health risk to the recipient in terms of taking medications not prescribed to them.6 When medications are returned via appropriate pathways (eg pharmacies, hospitals) the drugs are usually incinerated along with general medical waste.11
The purpose of this paper is to explore the environmental harm of PW and examine methods of mitigating this problem within the dental sector.
A literature search using PRISMA methodology was conducted on pharmaceutical waste, full details of which can be obtained from the authors. In total, 34 papers were analysed, and the findings are discussed below.
Medication prescribed in dentistry is disposed of in conventional waste systems, such as clinical/domestic waste destined for landfill, flushed into the water system or incinerated.
Figure 2 shows the source, current and possible management of drug waste, and its harm to both the planet and human health.
The inappropriate disposal of dental associated medication can interfere directly with the health of the planet (eg air pollution and water pollution) with indirect human health consequences. In addition, PW can impact directly on human health, for example through antimicrobial resistance.
The degree of harm caused to the environment by PW is debatable. On one hand, it is felt that although contaminants of PW exist in the environment, levels are so low as to evoke uncertainty as to the degree of harm they actually cause.12 In addition, arguments exist that the leaching of pharmaceutical pollutants into water systems can be attributed as much to the unavoidable metabolites of these medicines (through human excretion) and, therefore, not a direct result of unused medication.13 Regardless of route of entry or quantity, one can assume that any trace of PW found in drinking water is undesirable.
A key area of environmental harm in regards to drug waste is the contamination of global water systems. This increasing problem sees entry being gained commonly by medications being flushed down sinks and toilets into sewerage systems.3,14,15,16 In addition, medication that is found in landfills has the potential to access groundwater and surface water.8,17 Complete removal of these chemicals by water treatment plants is never completely successful. Not only does this result in traces found in drinking water, but it is also believed that pharmaceuticals disrupt the treatment processes by destroying beneficial bacteria.1,12,14,18,19,20
The use of incinerators to burn PW leads to toxic emissions in the form of heavy metals and toxic gases being released into the air. This is especially the case when these chemicals are burnt at low temperatures.20,21,22 It should be noted that none of the literature reviewed stated exactly what harm the release of the toxic gases caused.
Dentists commonly prescribe antibiotics, with antimicrobial resistance the primary concern in relation to their disposal.10,23,24 One study showed that bacteria tested from a river in China, noted for its high level of pollution of antibiotics, displayed antibiotic resistant genes.14 This in turn leads to the spread of antibiotic-resistant bacteria, a recognized ‘global health challenge’ that impinges on the fight against disease.25
Another medication that is prescribed in dentistry, diclofenac, is a non-steroidal anti-inflammatory. In 2012, there were in excess of 10 million such prescriptions issued worldwide.26 Diclofenac has been shown to have several negative implications on the environment, largely a result of its capacity to hamper renal function. Trout have been implicated in this harm and several studies have reported in Asian countries that vultures who ingested dead cattle (with high diclofenac levels), have been harmed.10,27
The management of PW also has implications for social equality. Regardless of how waste is managed, evidence suggests that poorer communities face a disproportionate burden from the harm from these waste emissions.21 In the US, it has been noted that there is a higher proportion of incinerator sites located in low socio-economic areas and also that dump sites used toxic ash from incinerators was disposed of at dump sites near disadvantaged areas.20
Several methods of mitigation of PW have been addressed in the literature with some focusing on management and others on prevention.
Drug take-back schemes have been introduced in several countries. There is currently no known mechanism for dentists to participate in these programmes. In some jurisdictions, members of the public can either return unused medications directly to the pharmacy or at ad hoc drop off sites on scheduled days (Figure 3). This encourages an end to the practice of storing excess medication in homes and related harmful disposal methods.21,28 Several of these take-back programmes have seen success, with one programme running over the course of 7 days collecting 1733 tons of medication.6 In contrast, a take-back scheme in Ireland, Dispose of Unused medications Properly (DUMP), has not seen the same success owing to its intermittent availability.12 Anonymity also appears to be a factor in the success of these programmes, with many participants feeling more comfortable disposing of the medicines into containers rather than handing them directly to pharmacy employees.24
Incineration of all waste types is a popular method that is used worldwide. It causes oxidization of the active ingredients causing them to be deactivated. On one hand, this removes the potential for unused medicines to contaminate water systems, but on the other it leads to the release of harmful emissions.20 If this type of waste management is used, it should be carried out in incinerators capable of burning at high temperatures to reduce the amount of leach metals released.8,20
Attempts have been made to deactivate the active ingredients in waste medications. Chemicals including sodium percarbonate and sodium carbonate have been used in oxidation and hydrolysis processes to this means. Activated carbon has proven to successfully deactivate amoxicillin after 7 days. This renders the medication safer when in contact with the environment.1,29 As there are no emissions released in this process it would seem a more environmentally friendly alternative to incineration and could be explored as a disposal method used at domestic level.
Segregation of PW, especially in both hospital and domestic settings, should be done at source. This reduces the risk of the waste being discarded by less suitable means.30
Recycling of unused medication is another idea that has been explored. In Singapore, one study found that over 90% of donated medicines were suitable for recycling. Redistribution of this medicine was not only beneficial for the environment, but also to people in lower socio-economic groups who could not afford their prescribed medication and benefited directly from the donated medications. Extension of this type of practice has been resisted in many countries over safety and fear of drug tampering.9 A 2016 study showed that many of the stakeholders had a positive attitude to medication recycling.31 Exploring the reasons for acceptance by these participants might help make drug recycling a more commonly accepted practice and lead to the creation of similar programmes to that in Singapore.
Education is the most cited means of tackling the issue of PW and needs to involve dental prescribers, pharmacists and the general public. Although no studies have been carried out in dentistry, studies in generic healthcare have shown that when patients receive relevant information on the environmental effects of PW, they are more inclined to use proper disposal methods.12 In one study, over 80% of participants admitted they had not received information on correct methods of PW disposal. Of those who had received this information, over 50% took unwanted or unused medication to designated waste collection facilities or to a pharmacy, in comparison with just over 10% of people who were not similarly educated.17
The management of PW, like many public health concerns is a complex problem that needs to be tackled prophylactically, that is by reducing prescriptions to reduce waste. In Canada, a 2016 study showed that dental prescriptions were increasing.32 Dentists should be discouraged from developing a practice of being too quick to write prescriptions. Irreversible pulpitis is an inflammatory condition of the dental pulp with a bacterial origin. Antibiotics are frequently prescribed to manage the symptoms. A 2013 Cochrane review found the use of antibiotics did not offer a significant reduction in pain. While time constraints make practitioners reluctant to carry out same-day treatment, it should be remembered that the most effective means to treat this problem is through drainage and not by writing a prescription.32
Regular reviews of repeat prescriptions will help ensure only relevant medication is included in each dispensed prescription. Another approach to reduce waste is to shorten prescription lengths for chronic conditions. As mentioned, one of the reasons for PW is early cessation of medication due to the patient developing an adverse reaction. If the prescription length is restricted, it will reduce the amount of unused medication if the patient needs to discontinue prematurely. The prescription length should only be extended once compatibility between the patient and the medication has been established.9 Daughton explored the concept of ‘eco-derived sustainable prescribing’ and found that while changing the prescribing behaviour of prescribers would be challenging, it would have a positive effect on the environment.33 Similarly, the concept of ‘pharmacoEcovigilence’ was touched on briefly as a means of reducing the ‘ecological footprint of medications’.34 Regardless of the medical discipline, the adoption of the preventive approach through diet, exercise and better lifestyle choices will reduce the number of required prescriptions, in effect reducing the amount of waste produced.33
Educating the public in regards to non-compliance of medication taking is a practical approach to the issue of PW. In the case of antibiotics, it should always be reinforced that an improvement in symptoms does not mean the infection has completely cleared and finishing a prescription is vital to reduce the risk of re-infection as well as preventing antibiotic resistance.21 When there are unwanted side effects to a medication, patients should be advised on suitable means of disposal, and take-back programmes should be provided by pharmacists. Research shows that consumers have a positive attitude to receiving information on correct disposal practices, demonstrating the willingness among the public to behave responsibly.10,35 When informed about such programmes, 30% of informed people returned unused medication to take-back schemes compared with up to 7% of those who were uninformed.17
One issue on the advice of waste disposal by healthcare professionals was that 36% of pharmacists reported that they have not received formal training on drug waste disposal.5 While none of the literature addressed this in regards to dentists, it could be assumed that this is an area of concern in the dental industry. This can easily be addressed in the curriculum of pharmacy and dental students so that they feel better equipped at discussing and advising patients on this topic.15
Government-led national campaigns to highlight the link between PW and environmental harm should be introduced. A principle of ‘the polluter pays’, which has been implemented in several countries, puts the onus on the pharmaceutical industry to tackle the problem, making them a stakeholder in the issue of the environmental impact of PW. This creates an incentive for the industry to promote responsible behaviour on drug disposal.24
Implementation of fines for pharmaceutical companies who are non-compliant with environmentally friendly waste collection producers could be an effective means of tackling problems surrounding PW.14,16
In Sweden, Belgium, France and Spain, it is the pharmaceutical industry who is responsible for collecting, transporting and treating household PW.14 Provision of ‘take-back’ programmes should be organized and funded by the pharmaceutical industry in conjunction with local pharmacies. The design of such a scheme plays a role in success, with consistent availability as well as preservation of anonymity observed as factors that will help increase returns.12,24
In Ghana, it is an offence to dispose of medication in such a way that can lead to food or water contamination and could impose a health risk.21 The South African government has legislated that the generator of healthcare waste be liable for the costs of cleaning waste and its environmental effects.30
A primary goal when disposing of PW is to ensure dental prescribed medication is safely and irretrievably removed from access by children or drug abusers.29 This approach does not factor in the environmental impact and therefore leads to environmentally harmful practices.
Addressing the causes of PW not only benefits the ecosystem, but indirectly peoples general health. Environmentally safe disposal practices like deactivation of harmful pharmaceutical compounds should be available. As healthcare providers, dentists need to reflect on the their role in this problem and act where possible, accordingly to ensure their practices don't impact negatively on the environment and in turn, their patients.
