We have discussed on the Clinical Waste Discussion Forum, over many years, the problem of drug residues in the environment. It is an issue in which we stand very much on the outside – considering sabre rattling at patients who might have the temerity to request a repeat prescription in favour of better prescribing practice as entirely misdirected, as is the regulatory concern about a few tablets present in clinical wastes, or the de minimis concentrations of drug residue in empty syringes.
Such a stance buys us few favours. However, we continue to support regulatory and other concerns about drug residues in the environment, though not the current approach that completely ignores the elephant in the room.
When drugs are prescribed, and for the over-the -counter products from the high street chemist, almost the complete dose is excreted in urine. It doesn’t matter what the drug is, it is excreted unchanged or metabolised and its metabolites excreted in urine. In almost every case, whet goes in comes out soon afterwards.
Those drug residues enter the environment, usually via the sewage system and the treatments that result in discharge of water free only of biological risks but often rich in drug residues. The quantities of these drug residues are vast, and explain the widespread contamination that just wouldn’t add up if the traces of drug substance that might be present in the treatment residues from ATT clinical waste treatments were a significant problem. In fact, these residues are so small in the overall scheme of things that they are truly infinitesimally small.
Some useful data comes to light in this months edition of The Lancet Infectious Diseases. There, Ted Alcorn presents a lengthy news item that is concerned with the ever-growing problem of antibiotic-resistant bacteria. In the US as elsewhere the use of antibiotics has grown dramatically over the last two decades. As Alcorn states, a few facts are indisputable: “The USA is awash in antibiotics, and livestock and poultry are the biggest consumers, taking more than 13 million kg of antibiotics in 2010 – four times more than people – as reported by the US Food and Drug Administration (FDA).”
Though Alcorn’s concern is – as my own – the impact on antibiotic resistance nothing is said about the fate of those antibiotics after administration. Some may enter the food chain. Others, excreted in urine and faeces will directly enter the environment without any treatment, very much as those drugs excreted by humans.
It would be wrong to deny that there is no work being done on improvements in wastewater treatment. However, progress is slow and as a diffuse problem it is most difficult to make any real change. Lean prescribing will help, together with positive action toward convenient community drug waste collection services. Reducing the use of unnecessary drug administration to farm animals, especially those used as growth promoters, must be rigorously enforced. As Alcorn states, the impact on animal health must be considered and an immediate blanket ban is unwarranted, at least until more effective vaccines are available in their stead.
It is equally wrong not to deal with smaller and lesser sources of contamination, for example those wastes from hospital and community pharmacies and hospital wastewater treatments etc though these are in place and working well, or showing early promise. Other regulatory attention begs the question, just where to stop?
Presently, the close focus by individuals on the presence of de minimis concentrations of pharmaceutical residues in clinical wastes seems entirely misplaced. It has been used belligerently, to manipulate the planning and regulatory processes. That is wrong and must stop.