The study, led by Sara M. Hanning of the University of Auckland’s School of Pharmacy with colleagues from the university and Middlemore Hospital, set out to answer three practical questions: how unwanted medicines are currently disposed of in community pharmacies, how many metered-dose inhalers are actually returned for disposal, and whether pharmacists would support a dedicated, low-carbon return scheme for inhalers. Between December 2023 and January 2024, an anonymous online questionnaire was emailed to 1,043 community pharmacies across New Zealand, drawn from the Medsafe pharmacy licence register. After reminders and data cleaning, 102 responses were complete enough for analysis, a response rate of roughly ten percent.

The headline finding was encouraging: 98 percent of responding pharmacies already collect unwanted or expired medicines for disposal, and most reported receiving returns at least weekly, with nearly 16 percent receiving them daily. The dominant disposal route was a dedicated pharmaceutical waste bin collected by a third-party contractor. In New Zealand, non-cytotoxic pharmaceutical waste is steam sterilised by autoclave and then sent to a dedicated landfill, because the country no longer operates any high-temperature incinerators for pharmaceuticals or other waste. Cytotoxic medicines are the exception, exported offshore for incineration.

But the survey also uncovered practices that fall short of the official pathway. Some pharmacies reported pouring liquid medicines down the sink, a method that introduces pharmaceutical compounds into wastewater, where they can persist through treatment plants and reach rivers and coastal waters. A handful of respondents said they returned unopened, in-date medicines to stock for re-dispensing, a practice the researchers warn against, since pharmacies cannot verify how medicines were stored once they left the premises. Others mentioned giving sealed, in-date medicines to medical aid charities or destroying controlled drugs by dissolving them into kitty litter. The variety of reported methods, the authors suggest, reflects a deeper problem: most pharmacists simply do not know what happens to waste after it leaves their premises. Only 15.7 percent felt informed or well informed about the fate of pharmaceutical waste, and 67.4 percent said they were not at all informed about the environmental impact of inhaler disposal.

The inhaler numbers were stark. Respondents estimated their pharmacies dispensed an average of 214 metered-dose inhalers per month, but received only about eight back for disposal, a return rate of under four percent. This aligns with earlier research showing that most consumers toss empty inhalers into household rubbish, despite consumer information leaflets instructing them to bring devices back to a pharmacy. Passive information channels, the authors conclude, are clearly not enough to change behaviour.

The climate stakes are considerable. Pressurised metered-dose inhalers accounted for 66 percent of inhalers prescribed in New Zealand in 2020, largely because they are cheaper than dry-powder or soft mist alternatives and better suited to patients who cannot generate the inspiratory force needed for powder devices, including children, older people and those with severe symptoms. The hydrofluorocarbon propellants they contain were introduced to replace ozone-destroying chlorofluorocarbons after the Montreal Protocol, but they are powerful greenhouse gases. A common propellant, HFA134a, has a heat-trapping potential roughly 1,300 times that of carbon dioxide, and a typical 200-puff salbutamol inhaler carries a footprint equivalent to 28 kilograms of carbon dioxide, comparable to driving a petrol car more than 120 kilometres. Because manufacturers fill canisters with excess propellant to guarantee every dose, gas remains even after all the medicine is used, and it lingers in the atmosphere for an average of 15 years.

When asked whether they would be interested in a dedicated recycling scheme for metered-dose inhalers, 42.7 percent of pharmacists said yes and 39.3 percent said maybe, with only 18 percent declining. The two biggest barriers, ranked by a weighted scoring method, were the administrative load on pharmacy staff and the financial cost to the pharmacy. The small number of inhalers returned by consumers ranked lowest among the barriers. Free-text comments captured the tension: one pharmacist wrote that they would want to know the procedure and full rationale first, since delivering medication was the priority and environmental concerns secondary; another noted that pharmacies spend significant staff time on returned medicines with no financial reimbursement, calling it yet another service community pharmacies provide for free.

Pharmacists also had clear views on what would motivate patients. Media advertisements promoting the scheme and financial incentives for returning inhalers ranked highest, while reminders at the point of dispensing ranked lowest, echoing the finding that passive advice has little effect. International evidence suggests such schemes can work. A 12-month postal pilot in one English region collected more than 20,000 inhalers, 77 percent of them pressurised devices, and recycled the propellant gases for refrigeration, the aluminium canisters into smelting bricks and the plastic casings into pellets, preventing an estimated minimum of 119 tonnes of carbon dioxide equivalent from entering the atmosphere. Yet scale matters: the UK’s Complete the Cycle scheme, which recycled two million inhalers over nine years, closed in 2020 because its creator concluded that a standalone scheme could not achieve adequate scale without industry-wide cooperation. In New Zealand, a six-month inhaler recycling trial began in the Bay of Plenty in June 2025, and a refrigerant destruction facility using plasma arc technology is under construction in the North Island, potentially offering a domestic route for capturing and destroying propellant gases.

The researchers argue that a product stewardship model, in which responsibility is shared across manufacturers, importers, distributors, pharmacies and consumers, may be the fairest path forward, with pharmacies forming one link in a larger technological chain. New Zealand already has precedent for such schemes with synthetic refrigerants, and the regulatory and administrative infrastructure exists. To ease the burden on pharmacies, the authors propose a scheme that integrates seamlessly with existing medicine return systems, supported by centralised automated administration, government funding, space-conscious collection containers and regular scheduled pick-ups. Consumer-side measures could range from money-back incentives on prescription costs, as trialled in Sweden, to low-cost local prize draws like one running at a general practice on Vancouver Island, Canada.

The study has limitations the authors acknowledge candidly. The ten percent response rate, likely worsened by staffing shortages, pharmacist burnout and the timing of invitations over the Christmas and New Year holiday period, means the sample may over-represent pharmacists already interested in sustainability, potentially inflating estimates of willingness to participate. Still, the direction of the findings is clear: pharmacies overwhelmingly accept returned medicines, most feel responsible for safe disposal, and most are open to an inhaler scheme if cost and paperwork are addressed. The next phase of the research will use semi-structured interviews with pharmacists and inhaler users to map barriers and encouragers in more detail, alongside work to establish cost-effective pathways for emptying and decontaminating canisters so that aluminium and plastic components can re-enter the circular economy. With New Zealand committed to cutting net carbon dioxide emissions to 50 percent below 2005 levels by 2030 and reaching net zero for most greenhouse gases by 2050, capturing the greenhouse gases hiding in medicine cabinets and rubbish bins may prove one of the quieter but more achievable wins in healthcare’s climate transition.

Subject of Research: Pharmaceutical waste disposal practices in community pharmacies and the feasibility of a low-carbon return scheme for metered-dose inhalers in New Zealand

Article Title: Disposal practices for unwanted medicines in New Zealand community pharmacies and their willingness to support a low-carbon return scheme for metered-dose inhalers

Article References: Hanning, S. M., Barnes, M., Burrell, R., & Aspden, T. J. (2026). Disposal practices for unwanted medicines in New Zealand community pharmacies and their willingness to support a low-carbon return scheme for metered-dose inhalers. Clean Technologies and Environmental Policy, 28(10), Article 262. https://doi.org/10.1007/s10098-026-03622-5

Image Credits: AI Generated

DOI: 10.1007/s10098-026-03622-5

Keywords: community pharmacy, pharmaceutical waste, metered-dose inhalers, hydrofluorocarbons, greenhouse gas emissions, inhaler recycling, New Zealand, planetary health, medicine disposal, product stewardship, environmental sustainability, asthma