Parasiticides for cats and dogs: a rational approach. Module 6. Creating a practice policy

Why do this module?

UK veterinary professionals have to deal with an increasing number of parasite threats to companion animals and a very large and growing range of parasiticide products with which to control them. This can be a source of confusion in any veterinary practice and clients may get conflicting messages from different members of the practice team about parasite protection for their pets. A practice parasiticide policy will help ensure that there is a consistent message about parasiticide protection from every member of the practice team, that parasite risk is reliably assessed for each animal, and that the products best suited to the animal’s needs are chosen.

A practice parasiticide policy is a system or protocol that ensures that the advice given to clients has a consistent basis throughout the practice and, through a risk-based approach, that there is reliable assessment of an individual animal’s risk of parasite infection and the factors that affect product choice. This will lead to a product recommendation tailored to the individual animal and will also help determine the most appropriate range of products to stock without unnecessary product overlap. A policy is not simply a list of products, because pets need to be assessed as individuals.

There are many advantages:

  • It ensures that all relevant parasite risks are considered - Systematic collection of information about the animal will ensure that risk is assessed for all relevant parasites and none missed.

  • Animals will not receive unnecessary medicines - Assessment of risk and lifestyle will ensure that pets only receive necessary medication.

  • Collection of information can help educate clients about parasite risks and the need for protection. It can also help uncover clients’ beliefs and understandings about parasiticides and the likelihood of correct and consistent use of products (e.g. concerns about adverse effects; not understanding why treatment is needed if their pet is not unwell).

  • Information can be collected more efficiently – There might be insufficient time during a 10-minute veterinary consultation to collect all the necessary information. A practice policy can ensure that the information is collected before the consultation, for example through the use of questionnaires in reception or in nurse clinics. The veterinary consultation time can then be used to recommend appropriate products.

  • Tailored advice and a consistent message will help increase client trust – Mixed messages about parasite risks and about product recommendations could lead to a loss of trust and lack of protection for the pet. If the recommendations are always the same for everyone, regardless of individual need, clients may be tempted to source the products elsewhere because they consider practice advice redundant.

  • Increased sales – If clients are confident that the recommended treatments are necessary and the pets' needs reviewed regularly, they are likely to remain bonded to, and continue to buy the recommended treatments from, the veterinary practice.

  • Meet RCVS Practice Standards Scheme (PSS) criteria (RCVS PSS Small Animal Modules and Awards 2015) The Small Animal Module of the PSS (section 10.1.28) requires that “a practice must be able to demonstrate that when using anthelmintics it does so responsibly and is accountable for the choices made in such use " The optional Awards at section 10.5.23 ask that “the practice has a protocol for endo and ecto parasiticide use” which “should have been drawn up following clinical team discussion and considering the evidence base”. The evidence for this would be an example of a written protocol.

  • It will encourage clinical discussion and consistency of advice without interfering with clinical freedom.

  • It has “One Health” benefits. As well as benefiting the health of the pet, in many cases parasite control has human health benefits too.

A practice parasiticide policy needs to be designed to lead to a specific, bespoke recommendation on parasite control for a specific animal. This will include taking account of:

  • parasite threats in the UK in general and in the locality.

  • the lifestyle of the pet and owner

  • factors affecting the likelihood of the owner using parasiticides correctly and consistently.

The policy should specify what information needs to be collected, and where and how this will be done. A product or products can then be selected to meet these needs.

Ideally all practice staff should be involved in developing the parasiticide policy. Some aspects will require the knowledge and expertise of veterinary surgeons or nurses, but some aspects, such as how to collect information and how to phrase questions and engage clients can involve the whole practice team. It can be helpful to have a project champion in the team whose job it is to manage the task. An enthusiastic champion can help get the job done and can benefit from the learning progression that the project will bring.

Ideally all practice staff should be involved in developing the parasiticide policy. Some aspects will require the knowledge and expertise of veterinary surgeons or nurses, but some aspects, such as how to collect information and how to phrase questions and engage clients can involve the whole practice team. It can be helpful to have a project champion in the team whose job it is to manage the task. An enthusiastic champion can help get the job done and can benefit from the learning progression that the project will bring.

The risk of the animal being infected with parasites that are likely to cause morbidity or have zoonotic potential can be assessed through the answers to a series of simple questions. This can be done by asking clients directly, asking them to fill in a questionnaire or by reviewing the animal’s history. A full picture may develop over several visits to the practice rather than at one consultation or through “flea and worm clinics”. 

All pets need protection against fleas and roundworm. The following four questions will help determine the appropriate level of roundworm protection and the need for protection against the other main parasites – ticks, tapeworm and lungworm.

Question 1: Is your pet in regular contact with young children, or a person with a condition, or on medication, that suppresses the immune system? If so, monthly rather than 3-monthly roundworm treatment is recommended. (ESCCAP 2010)

Question 2: How often have you seen a tick on your pet? A history of tick attachment strongly suggests that the pet’s lifestyle exposes it to ticks. 

Question 3: Does your pet eat raw food or hunt? Dogs that eat raw offal might be at increased risk of Echinococcus infection for which regular treatment with praziquantel is recommended. Dogs and cats that eat raw diets or hunt may also be at increased risk of Toxocara infection and need treatment for roundworm monthly rather than 3-monthly. (ESCCAP 2010)

Question 4: Does your dog eat grass or slugs or snails? Such behaviour together with knowledge of local Angiostrongylus vasorum prevalence will indicate if the dog is at increased risk of infection with A. vasorum (‘lungworm’).

Further questioning will help determine the best type of product to use. Correct and consistent use of products is arguably the most important factor when selecting parasiticides. Parasite control will fail if a product is difficult to use or not used because it has previously caused adverse effects in a pet. The client should be asked what type of product formulation they prefer, and about any history of the pet vomiting on tablet medication or having skin reactions to specific spot-on applications and collars. Clients are often concerned about toddlers or babies being exposed to topical treatments. The choice of product might also be affected by other pets in the household (e.g. spot-ons containing permethrin would be unsuitable for a dog sharing a home with a cat). Contact with water may wash out a topical product making it less effective: it might therefore need to be applied more often or an oral product used instead. Asking open questions is an opportunity to discuss any concerns.

For example: what have you used before? How did you get on with it? Do you think it worked? Did you notice any unwanted effects?  Are there children in the  house? Does the dog’s coat get wet regularly (e.g.  through bathing or swimming)?

Applying a product in the surgery is an option if all formulations are problematic for the owner.

To save you time we have put together an example of a client questionnaire that you can use to ask basic questions about parasite risk and product suitability before the veterinary consultation. Click the button to view and print.

Having established the parasite coverage needed and the factors that affect choice of formulation, a single product or combination of products can be selected. When selecting products there are several more features to consider.

  • Duration of action – Flea and tick control rely on the products having a prolonged effect after administration. The frequency of use ranges from monthly (for spot-ons, sprays and some tablets) to 3-monthly for some spot-ons and tablets, to 4–8 monthly for collars. The Parasiticide Guide will help with choice. Most oral worming products do not have a prolonged effect and successful control depends on treatment frequencies being shorter than the pre-patent period of the parasite, or sufficiently frequent to keep parasite numbers below disease thresholds and/or reduce environmental contamination.

  • Speed of kill and repellency of flea and tick treatments - Flea adulticides need to kill fleas within 24 hours to prevent egg laying, but in cases of flea allergy dermatitis, a more rapid killing effect is desirable to limit exposure to flea saliva. According to current regulatory standards, products for treating and preventing flea infestation have to be shown to reduce adult flea count (following deliberate infestation) by at least 95% within 48 hours of application of the treatment. (CPMP 2008) For many of the newer flea products there is evidence that their onset of action (speed of kill) is sooner than 48 hours. The European guidelines for testing parasiticides are being revised and so all future new products will undergo testing that will include assessment of speed of kill sooner than 48 hours. (EMA 2015) The tick-borne diseases in the UK (Babesiosis and Lyme disease) are thought to take at least 24 hours to be transmitted after a tick bite, (ESCCAP UK&Ireland) so use of a tick product that repels ticks or kills them within 24 hours of arrival on the pet will help to prevent disease transmission (for more on this see Which tick product?).

  • Adverse drug reactions – Adverse drug reactions are rare if licensed products are used at recommended dose ranges and frequencies. Potential adverse effects are listed in the relevant SPCs. Suspected adverse events should be reported to the VMD.

  • Drug interactions – It is important to be aware of known and potential interactions between parasticides and other therapies or between different parasiticide products. For example, using two products containing a drug in the same class (such as a tablet containing milbemycin + praziquantel together with a spot-on containing moxidectin + imidacloprid) might increase the likelihood of adverse effects due to the macrocyclic lactones (milbemycin and moxidectin). To avoid this interaction, tapeworm cover can be provided with a tablet containing praziquantel alone together with the moxidectin/imidacloprid spot-on. Report suspected drug interactions to the VMD.

  • Use in pregnancy and lactation – The SPC should always be checked for safety information about use in pregnancy and lactation where necessary. The Parasiticide Guide can be used to help identify suitable products.

  • Impact on the environment – There is a lack of evidence on the impact of companion animal parasiticides on the environment. However, the release of substances used in topical formulations into the environment and the disposal of small quantities of veterinary medicines to landfill are a potential route for environmental contamination with parasiticides. (Boxall 2010)

  • Resistance - There is no clear evidence of the resistance of companion animal parasites to parasiticides in the UK. Reports of lack of effect are often assumed to be due to resistance, but are difficult to prove and may be due to incorrect product use or incomplete control of the parasite lifecycle (e.g.lack of environmental flea control). (Coles & Dryden 2014) Suspected lack of effect of a product should be reported to the VMD.

  • Cost – The cost to the client of parasiticide therapy should be considered. If the treatments are not affordable or perceived to be expensive they will not be used. There is an enormous choice of products, including many branded generic versions of well-known brands. The Parasiticide Guide will help you. If a complete range of parasiticides is not affordable then the most important should be selected for preventive treatment. Seasonal variation in products used according to risk might also increase affordability.

By predicting the common needs of pets in the practice population it is possible to restrict the range of products stocked in the practice to a few that cover the most common needs. Other products can be ordered as needed for specific or unusual needs (e.g. for pets travelling abroad). The Parasiticide Guide will help identify products for specific needs.

Plans that include services such as vaccinations, parasiticides, health checks and advice for a fixed annual cost, usually split into 12 monthly payments, are becoming more common. They have many advantages, including regular monthly income for the practice and they help ensure regular use of preventive therapies. However, plans define product choice which means any product not on a plan has to be bought separately. For instance, in practice vets might have to choose between preventing ticks or lungworm because choosing non-plan products is more costly to the client. It is therefore important that the practice establishes a parasiticide policy based on the practice pet population so that the individual needs of pets can be incorporated into a health plan.

The core products stocked in the practice might need to change as new products are launched or the needs of the client base shift with time.

There should be a system in the practice for keeping practice staff up to date with parasite risks and new products, and for deciding whether changes are needed to the policy or product range stocked.


If you prefer, you can listen to the whole audio presentation of this module using the following podcast. Don't forget that you can also download the podcast to your iPod, music player, tablet or smartphone using the Download link on the right of the audio player.

Goal of activity: Update knowledge; develop a practice policy

Authors/disclosures: Veterinary Prescriber editorial team/no conflict of interest

Specific learning objectives: to develop a practice parasiticide policy

The following are suggested practical exercises for practice staff that will help with the creation of a practice parasiticide policy.

How we produced this module

Our modules start with a detailed outline and electronic literature search. We commission a collaborating author, who is a specialist in the module topic, to write a draft module. The collaborating author on this module was Ian Wright. The draft is circulated unsigned to a wide range of commentators, include practising first-opinion vets, other topic specialists, the companies that market any mentioned drugs and other organisations and individuals, as appropriate. They can raise points about the interpretation of evidence, ask questions that are important to clinical practice, and present alternative viewpoints. There is a rigorous editing and checking process and the result is a module that is evidence-based, impartial and relevant to clinical practice. The final module is unsigned because it is the result of collaboration. 


Boxall ABA. Veterinary medicines and the environment. In: Cunningham F et al (eds). Comparative and veterinary pharmacology. Handbook of Experimental Pharmacology 199. Springer-Verlag Berlin Heidelberg 2010.

Coles TB, Dryden MC. Insecticide/acaricide resistance in fleas and ticks infesting dogs and cats. Parasites Vectors 2014; 7: 8.

Committee for medicinal products for veterinary use, 2008. Guideline for the testing and evaluations of the efficacy of antiparasitic substances for the treatment and prevention of tick and flea infestation in dogs and cats.

European Medicines Agency. Guideline for the testing and evaluation of the efficacy of antiparasitic substances for the treatment and prevention of tick and flea infestation in dogs and cats. Draft. 2015.

ESCCAP. Worm control in cats and dogs. ESCCAP guideline 01 second edition. September 2010.