Pharmacies are being asked to take more responsibility for disposing of unused medicines appropriately.

Writing in the latest Journal of Primary Health Care, Alfred Tong, Barrie Peake and Rhiannon Braund (all of the University of Otago, Dunedin) say that there are no official guidelines in New Zealand for the disposal of unused and unwanted medications.

"However, one of the recommended methods to dispose of unwanted pharmaceuticals in many countries, including New Zealand, is to return them to pharmacies."

That puts a great deal of responsibility on individual pharmacies, which commonly report that tablets, capsules and ointments are collected by contractors and incinerated, as are Class C controlled medications.

However, more than half of surveyed pharmacies report pouring liquid medications directly down the sink or flushing them down the toilet. For Class B controlled drugs, the numbers are even higher, with nearly three quarters being disposed of this way and only 23.3% of pharmacies reporting using a contractor.

The authors say this has the potential to negatively affect the environment. "It is unknown how efficiently sewage treatment facilities in New Zealand remove trace levels of pharmaceuticals from sewage waste streams". This can have significant impacts on food sources and wildlife.

"For example, the commonly-used non-steroidal anti-inflammatory drug diclofenac has been shown to induce renal failure in vultures following the ingestion of [meat] from cattle treated with the drug."

Around the world, traces of pharmaceutical residues have been detected in effluents from sewerage facilities, surface water and even drinking water.

The authors say that more should be done to minimise the potential environmental risk. "? Community pharmacies in New Zealand need to dispose of all medications responsibly.

"Community pharmacists should also have an increased awareness of the potentially detrimental effects on the environment arising from improperly disposed-of medications."

There is no safe and funded national disposal system available for liquid drugs. Most of the pharmacists surveyed support the idea of a state-run disposal scheme accessible to pharmacies across the country.