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Pharmaceuticals: Commercial pressures to pollute (unwittingly)

 

(by Andrea Tarr, Veterinary Prescriber, 14 August 2024)

 

I moved house a few months ago. After handing over the keys to my new home, the estate agent presented me with a gift box. How lovely! I said. Don't get too excited, she responded. When I got home and opened the box I understood what she meant. This was not an act of generosity, it was the transfer of a collection of free samples -- a marketing strategy used by companies to introduce new products to consumers.

 

Apart from a welcome bottle of drink and some biscuits, the box consisted of trial sizes of laundry products. One of these - a pack of tumble-dryer sheets - promised to "revitalise your clothes with the freshness of spring flowers". There was a reassuring message on the sachet about the sheets being recyclable. But also, in tiny print, were the words "tumble dryer sheets: harmful to aquatic life with long lasting effects". What did this mean? Would the sheets harm aquatic life if I used them as intended, or only if I put them directly in a river? Could the toxic ingredients transfer to clothing in the tumble dryer, leach out at the next wash, then travel via waste water into rivers?  How was I supposed to act on this information?

 

After effects

 

We're not used to thinking about the effects of products or their ingredients after we've finished with them. This is true of pharmaceuticals. I began my career as a pharmacist around 40 years ago. In most of that time I never thought, or heard anyone talk, about the effects of medicines beyond their actions and fate in the body.

 

But now pharmaceuticals are being found to be polluting rivers all over the world. They get into rivers via waste water following excretion from human bodies, or after disposal, or in waste derived from pharmaceutical manufacture. In the environment the drugs in pharmaceutical products (along with any break-down products) can continue to have biological effects, for instance affecting fish reproduction and behaviour and potentially adversely affecting human health. It's not only the inherent effects of the pharmaceuticals and their presence in water that are of concern. There is much more to understand, including whether they get into sediments and soil, how long they persist, whether they accumulate in organisms (bioaccumulation), and the effects of several of these substances together. All of this is a relatively new area of research.

 

Veterinary pharmaceuticals

 

In the veterinary sector, it has long been recognised that the treatment of cattle with the anti-inflammatory analgesic diclofenac is lethal to vultures who have fed on the carcasses of treated cattle; consequences for human health are now coming to light.

 

The veterinary pharmaceuticals that have come under the spotlight more recently in the UK are flea and tick products for cats and dogs, in particular the active ingredients fipronil and imidacloprid, which are polluting UK rivers. These insecticide ingredients in spot-ons and collars remain on the animal's body after application; they can rub off onto hands and textiles and then wash into waste water. Researchers are now mapping how these substances travel from treated pets to our rivers.

 

What can be done about parasiticide pollution?

 

One response to the discovery of fipronil and imidacloprid pollution is a call for a ban on their use in pets and a swap to using products that are absorbed into the animal's body. But these suggestions might just move the problem elsewhere. Effective available alternatives to fipronil and imidacloprid, such as isoxazolines, are long-lasting insecticides that reach the environment in a different way from fipronil and imidacloprid (mainly via the treated animal's faeces) and their fate is even less-well researched. So when there is a call for the use of safer alternatives to fipronil and imidacloprid, it's not yet clear what these are.

 

Regulation protects the environment, doesn't it?

 

The aim of UK veterinary medicines regulation is to protect animals, people and the environment from harm. Consequently veterinary medicinal products are risk-assessed before companies are granted marketing authorisations for them.

 

However, medicines for use in companion animals (as opposed to food-production animals) are exempt from a full environmental risk assessment because use in individual companion animals has been assumed to pose a negligible environmental risk. This now seems a naive assumption, considering the widespread use of parasiticides in a population of cats and dogs that has grown to more than 20 million in the UK. Changing the regulations to require a full environmental risk assessment before the products are marketed is logical, but will take time and it may not be possible to find effective products that are completely safe.

 

Do we overuse parasiticides?

 

In human medicine, the quantity of pharmaceuticals reaching the environment is driven partly by unnecessary or excessive use.

So it's reasonable to consider whether this happens in veterinary medicine too. It's difficult to know if parasiticides are being overused; sales data on cat and dog parasiticides are not collected and published, as they are for antimicrobials. It's worth considering whether market and regulatory conditions may be encouraging overuse.

 

Wide availability and easy access because of deregulation

 

New veterinary medicines, including pet parasiticides, start out as prescription-only products (POM-V).

 

When they've been on the market for at least 5 years and have a good safety record (in treated animals and humans handling the products), companies can apply to the regulator to supply the products without a prescription.

 

[The supply category POM-VPS (which stands for prescription-only medicine - vet, pharmacist, SQP) includes products used in food-production animals - mainly parasiticides, vaccines, and vitamin and mineral supplements. In practical terms, the POM-VPS category differs from POM-V in that the animal does not have to be under the prescriber’s care.]

 

For cat and dog parasiticides, there are two levels below the prescription-only category. The next one down is NFA-VPS (which stands for Non-Food-Animal - Vet, Pharmacist, SQP). Products in this category can only be sold by a vet, a pharmacist or a Suitably Qualified Person [SQP].

 

The lowest category (least regulated) is AVM-GSL (which stands for Authorised Veterinary Medicine - General Sales List). Products in this category can be sold (without professional advice) by any retailer (e.g. supermarkets).

 

In the last few years, there has been a stream of parasiticide brands containing fipronil or imidacloprid reclassified for supply without a prescription.

 

Deregulation reflects the safety of the products in treated animals and humans, but as mentioned above, it can say nothing about potential harm to the environment because veterinary drugs for the small animal market do not require environmental risk assessments.

 

Deregulation also enables easier access to the products for pet owners. It is important that pet owners can obtain effective flea treatments reasonably easily when needed. However, now that there is a new identified risk (to the environment) there are calls for parasiticides to be removed from general sale (AVM-GSL). If this happens, fipronil and imidacloprid products would still be available without a prescription from retailers that employ a vet, SQP or pharmacist.

 

While vets can prescribe parasiticides containing a range of other ingredients, there are few alternatives to fipronil or imidacloprid that a SQP or pharmacist can sell, although it seems possible that oral isoxazoline parasiticides will be reclassified for over-the-counter supply, as has occurred recently in the EU.

 

Removal of products from the AVM-GSL category could have another consequence - that pet owners would instead buy products classed as repellents; these are regulated as pesticides, have no proven efficacy and their environmental effects are unclear. It is also crucial that alternatives to fipronil and imidacloprid are not seen as environmentally risk-free options until we know enough about their environmental safety.

 

A focus on preventive use

 

Removing parasiticides from general sales as a way of reducing the pollution risk assumes that vets, SQPs and pharmacists will be reliable custodians of the environment when making sales. UK veterinary surgeons' professional organisations have advised that vets should have conversations directly with clients to assess individual pets' parasite risk to mitigate the environmental risk. Also, under the RCVS’s new “under care” guidance, vets must perform a physical examination as part of their initial clinical assessment of an animal before prescribing prescription-only parasiticides, in the interests of anti-infective stewardship. Some pet owners may be discouraged from obtaining treatment for a flea infestation if it is necessary to pay a consultation fee per pet. Nevertheless, in practice it appears that individual vets have little influence on parasiticide use when clients are automatically signed up to year-round supplies of the products through practice pet health plans. And in the non-prescription sector, parasiticides are now offered through subscription and box schemes, to encourage year-round use.

 

Advertising and sponsorship

 

Veterinary pharmaceutical companies have brought to market an extensive choice of effective parasiticide products for cats and dogs. There is fierce competition between companies for a share of the sales, and vets are the target of intense promotion. The most visible signs of this are extravagant exhibition stands at trade shows and advertising in journals and magazines. In a survey of two of the most commonly-read veterinary publications, most adverts were for cat and dog parasiticides. Companies also advertise non-prescription parasiticides to SQPs, pharmacists and pet owners. Some advertising campaigns have been emotive and others fear-mongering. Adverts naturally focus on the benefits of products and there is no requirement for adverts for veterinary medicines in the UK (unlike for human medicines) to include information about risk. Promotion also happens in other, more subtle, ways: through industry-sponsored professional advice and educational resources for veterinary professionals. Notably, the only national guidelines on companion-animal parasiticide management are sponsored by veterinary pharmaceutical companies that market parasiticides.

 

So what?

 

Marketing strategies are designed to increase product sales. They can persuade people to use products they don't need, or to use more than is necessary. While it's easy to conclude that fragranced tumble dryer sheets are unnecessary, parasiticides play an important role in maintaining the health of pets. However, unnecessary use of parasiticides means extra cost to pet owners as well as increased medicines pollution.

 

Pet owners trust veterinary practices and professionals to give unbiased advice. Preventative use of parasiticides should be based on evidence and evaluation of disease risk in the individual animal and not be influenced by vested interests. Like other medicines, it is inappropriate to sell parasiticides through indiscriminate subscription schemes and pet health plans, because these may promote unnecessary and continuous use. At the same time, any changes to the way parasiticides are supplied must be sure to maintain fair and affordable access to effective treatment for flea infestations when needed. A careful balance must be found.