How to dispose of unused and expired medicines

Every household eventually accumulates medicines that are no longer needed or have passed their expiry dates. Whether it is a leftover course of antibiotics, a changed prescription, or an over-the-counter remedy that has expired, deciding how to get rid of these products safely is an important aspect of public health. Improper disposal can lead to accidental ingestion by children or pets, intentional misuse, and environmental contamination. While it might seem convenient to simply throw medicines in the bin or flush them away, these methods can create secondary problems. Understanding the lifecycle of a medicine after it leaves the medicine cabinet helps explain why regulators and environmental agencies provide specific guidance on how to handle pharmaceutical waste. Safe disposal ensures that active pharmaceutical ingredients do not end up where they do not belong.

The environmental impact of pharmaceuticals in water

Active pharmaceutical ingredients (APIs) are the chemical compounds in medicines responsible for their therapeutic effects. When medicines are discarded improperly, APIs can enter the environment through several pathways. While a significant amount of APIs enter water systems through normal human excretion (when the body metabolises and passes a medicine), pouring liquid medicines down the sink or flushing tablets down the toilet introduces concentrated chemicals directly into wastewater.

Conventional wastewater treatment plants are generally designed to filter out biological waste and organic matter, not complex pharmaceutical compounds. As a result, these chemicals can pass through the treatment process and enter rivers, lakes, and groundwater. Even at very low concentrations, pharmaceutical residues can have ecological effects. For example, endocrine disruptors found in certain medicines can alter the reproductive systems of aquatic life, and the presence of antibiotic residues in waterways can contribute to the growing global problem of antimicrobial resistance.

Why flushing is discouraged

Historically, flushing unwanted medicines down the toilet was a commonly recommended method to quickly and permanently remove them from the home. Today, environmental scientists and health regulators strongly discourage this practice for the vast majority of medicines. The primary concern is the direct introduction of pharmaceutical chemicals into the water supply, which contributes to the environmental contamination described above. Modern guidance prioritises keeping all medicines out of the wastewater system whenever possible.

There are, however, a few narrow exceptions. Certain highly potent or controlled substances pose such a high risk of harm or fatal overdose if taken accidentally that some regulatory agencies maintain a specific "flush list." These agencies advise flushing these particular medicines immediately when a take-back programme is not readily available, weighing the immediate danger to people in the home against the environmental risk.

Take-back schemes and pharmacies

The most effective and environmentally sound method for disposing of unused and expired medicines is through formal take-back schemes. These programmes allow individuals to return unwanted pharmaceuticals to designated collection points, which are most commonly community pharmacies, hospitals, or municipal hazardous waste facilities. Once collected, these medicines are transported to specialised facilities for high-temperature incineration, which safely destroys the chemical compounds.

The availability of take-back schemes varies by region, but many countries require pharmacies to accept returns or host periodic collection events. In South Africa, the South African Health Products Regulatory Authority (SAHPRA) provides guidance on pharmaceutical waste, and many community pharmacies participate in take-back initiatives, acting as accessible drop-off points for the public. Checking with a local pharmacist is generally the best first step when looking to safely dispose of a medicine.

General guidance for household disposal

When a take-back scheme is not accessible, individuals may need to dispose of medicines in their household rubbish. To minimise the risk of accidental poisoning or misuse, certain steps are generally recommended. First, medicines should be kept in their original containers with the labels scratched out or blacked out to protect personal information. For solid dosage forms like tablets or capsules, they can be mixed with an unappealing substance—such as used coffee grounds, cat litter, or dirt—inside a sealed plastic bag. This makes the medicine less attractive to children, pets, or anyone searching the bin for usable drugs.

For liquid medicines, they can be mixed with an absorbent material like cat litter before sealing. The sealed container can then be placed in the general household waste bin. While this method is less ideal than incineration through a take-back programme, it is far preferable to flushing medicines down the drain or throwing loose, identifiable pills into an easily accessible rubbish bin.