How veterinary medicines get to market

A shopping trolley full of medicines

How it works

You can read or listen to our modules. There is a play button in each heading so you can listen while you read. Or you can listen to the whole module in one go or download it as a podcast. You'll find a play and download button for the whole module at the bottom of this page. At the end of the module there is a quiz, so you can test your knowledge and receive a CPD certificate. You will have to hit the play button on the quiz video and enter your name and email address before you start the quiz.

A veterinary medicine must have a marketing authorisation or meet certain criteria for exemption before it can be marketed in the UK. At the moment, a marketing authorisation can be granted in the European Union (EU) via the European Medicines Agency (EMA) and European Commission (EC), or in the UK via the Veterinary Medicines Directorate (VMD). It is still not known what effect Brexit will have on this. If there is a deal, the UK government is exploring the terms on which we could remain part of the EMA in terms of veterinary drugs. However, if there is no deal and the UK is no longer part of the EU regulatory framework for veterinary medicines, the UK will need to carry out functions currently done through the EU at the national level. (Defra 2018) This module sets out what is involved in the licensing of veterinary medicinal products (including generics) at the moment in the UK with examples to help relate it to practice.

By doing this module you will learn:

  • what is and what is not legally a veterinary medicine

  • how a veterinary medicine can be granted a marketing authorisation

  • what information is available on a licensed medicine and where to find it

  • how safety is assured and how to report adverse events.

The Veterinary Medicines Regulations 2013 use the Community law definition of a veterinary medicinal product (VMD July 2018; VMR 2013):

 “any substance or combination of substances presented as having properties for treating or preventing disease in animals; or any substance or combination of substances that may be used in, or administered to animals with a view either to restoring, correcting or modifying physiological functions by exerting a pharmacological, immunological or metabolic action, or to making a medical diagnosis.” 

A product may be a veterinary medicine because it falls within the first part of the definition and is medicinal by presentation; that is, the way it is presented gives the averagely well-informed consumer the impression that it treats or prevents disease. This may be through product labels, leaflets or other literature, or adverts or oral recommendations relating to the product issued before, during or after the sale. 

A product may be a veterinary medicine because it falls within the second part of the definition and is medicinal by function; that is, if it is used or given to animals with the aim of restoring, correcting or modifying physiological functions by exerting a pharmacological, immunological or metabolic action, or of making a medical diagnosis.

For example, cannabidiol (CBD); in September 2018 the VMD stated that it considered veterinary products containing CBD to be veterinary medicines on the basis that they fulfil the second part of the definition of a veterinary medicine (VMD September 2018). This means that without a marketing authorisation it is illegal to sell, supply or advertise CBD products for pets, with or without specific treatment claims. [Related module: CBD for canine arthritis].

Veterinary products may be considered borderline (non-medicinal) if they are both not medicinal by function nor by presentation. All veterinary medicines marketed in the UK must either have a current marketing authorisation, or be marketed under the terms of the exemption for small pet animals. (VMD July 2018; VMD December 2018b)

Herbal products are treated like any other products. They require a marketing authorisation if they are medicinal by presentation or function. For example, a product containing alkaloids, such as digoxin from Digitalis sp., would be considered medicinal by function. (VMD July 2018)

There is a simplified registration scheme for homeopathic remedies that are sold without medicinal claims, and when there is sufficient dilution to guarantee safety of the product. All new homeopathic veterinary remedies must either be registered under the scheme or have a full marketing authorisation. However, for homeopathic products that were on the market before 1 January 1994, a marketing authorisation is optional, provided no medicinal claims are made. They may continue to be manufactured and marketed without being registered under the simplified registration scheme because they were on the market when the scheme was introduced. These remedies have so called “Grandfather Rights”. Remedies manufactured from a biological source, nosodes or sarcodes are not included on this list. (VMD July 2018)

Nutraceutical products are foods or naturally-occurring food supplements that are marketed as having a beneficial effect on health. They are treated like any other veterinary medicinal products. They require a marketing authorisation if medicinal claims are made or if they contain certain ingredients that exert a pharmacological effect on the target animal. (VMD July 2018)

There are four ways to get a marketing authorisation (VMD November 2018):

The centralised procedure

This is used for most applications for medicines containing new active substances (also known as new chemical entities). It involves a single application to the EMA and a single evaluation for each product. It results in a single marketing authorisation being granted by the EC that is valid for the whole of the EU, including the UK. Certain medicines (such as biotechnology products) can only be licensed this way. It is optional for other veterinary medicines. Examples include grapiprant (Galliprant), imepitoin (Pexion) and oclacitinib (Apoquel).

The national procedure

This can be used when an application is sought in only one member state for products not already authorised in the EU. In the UK, applications are made to the VMD. It then issues marketing authorisations, which are only valid in the UK. Examples include acepromazine (AceSedate) 2mg/ml solution for injection for dogs and cats, amoxicillin (Amoxycare) 200mg tablets and enrofloxacin (Baytril) tablets 15mg (VMD product information database 2019).

Decentralised/mutual recognition procedures

The decentralised procedure involves an application for a marketing authorisation being submitted simultaneously to several member states, one of which takes the lead in the assessment. If successful, it results in identical national licences being issued in each state involved in the application. The outcome is an identical marketing authorisation in each member state issued by its national regulatory authority. The mutual recognition procedure is used when an applicant has an existing marketing authorisation in one member state and applies for authorisation in other member states. The other member state(s) is asked to mutually recognise the original marketing authorisation. Examples of products authorised by mutual recognition include Tralieve and Tramadog (both containing tramadol); and Eradia, Metrobactin, Spizobactin (all products containing metronidazole) (VMD product database 2019).

Exceptional marketing authorisations

A provisional marketing authorisation may be granted in the UK under exceptional circumstances without the provision of a full data dossier. This is usually only done when there is no suitable authorised medicine available to treat a particular disease or to treat a new disease in the UK. An exceptional marketing authorisation is intended to exist only for a short time and may be subject to special conditions. (VMD November 2018) Avian influenza vaccine (Nobilis influenza) is an example (VMD product database 2019).

An application must include all the necessary administrative information and scientific documentation necessary to demonstrate the quality, safety and efficacy of the product. (VMD November 2018)

What quality data are needed?

All applications must show that the product can be manufactured consistently and to a high level of quality. The sources and specifications of starting materials, especially active ingredients, are tightly controlled (e.g. the countries from which substances of animal origin are obtained are restricted), and the applicant must explain and validate the methods of manufacture and the control tests applied during and at the end of manufacture. Tight specifications are set for the final product, and its stability under different storage conditions must be confirmed. All manufacturing processes (including for active ingredients) must be performed under ‘Good Manufacturing Practice’ (GMP) in approved and inspected premises. (VMD November 2018) 

What safety and efficacy data are needed?

Applications for a marketing authorisation for a new medicine (‘Full marketing authorisations’) are based on a data package in which all parts of the data requirements related to its safety and efficacy are fulfilled using proprietary data (i.e. a company’s own generated data to support their product). When there is ‘well-established use’ (i.e. at least 10 years) some of the efficacy and/or safety data may be replaced by a bibliography (i.e. published data) or a mixture of new and published data. However, sometimes, the data package provided in support of a Full marketing authorisation may be reduced, for example, if the medicine is for a ‘minor use’ (e.g. rare diseases) or ‘minor species’ (e.g. goats, turkeys). (VMD November 2018)

The safety and efficacy requirements include:

• pharmaceutical (physicochemical, biological or microbiological) tests

• safety tests and residue tests

• tests assessing the potential risks to the environment from the product

• pre-clinical tests, such as determining the correct safe and effective dosage

• clinical trials to confirm the efficacy under controlled field (clinical use) conditions. (VMD November 2018)

For certain therapeutic areas (such as non-steroidal anti-inflammatory drugs [NSAIDs], antimicrobials and ectoparasiticides), there are individual guidelines outlining the type of evidence required to obtain a marketing authorisation. For example, the guidelines on efficacy studies for NSAIDs states that there should be at least one field study for each claim. (EMA NSAID guidelines 2014). 

When products already exist on the market with a claim similar to that of a new product, clinical trials for efficacy are generally performed in comparison to a reference product in order to avoid the unnecessary suffering of untreated control animals. Comparative trials must be designed to test that the new product is at least non-inferior in terms of efficacy. (EMA 2009) An example is imepitoin. (Related module: Imepitoin for idiopathic epilepsy in dogs)

Each application must also include a detailed description of the pharmacovigilance system and, where appropriate, the risk management system that the applicant will put in place to ensure that the safety of the product is monitored once on the market. Finally, all products must have an environmental risk assessment. An unacceptable impact on the environment will lead to the conclusion that the overall benefit:risk balance of the product is unfavourable and a licence will not be granted. (Murphy 2018)

One type of marketing authorisation is the ‘copycat’ or duplicate and is the result of an informed consent procedure. This means that, instead of providing new data, the applicant refers to data which the VMD has assessed previously in connection with another product. Applicants may do this when a product contains the same amount of the same active ingredient, and has the same pharmaceutical form (i.e. tablet, injection, etc) as a product already authorised, provided the authorisation holder gives consent in writing. In some cases, the second product is identical to the first in all respects except for its name. In this case it is described as a ‘copycat’. Examples include some Leptospira vaccines: two of the bivalent brands (Canigen Lepto 2 and Nobivac Lepto 2) and two of the quadrivalent brands (Canigen L4 and Nobivac L4) are identical (VMD 2019). Related module: Leptospira vaccines)

A generic medicine is a medicine that is developed to be equivalent in safety and efficacy to a medicine that has already been authorised, called the ‘reference medicine’. It contains the same active ingredient as the reference medicine, and is used at the same doses to treat the same diseases. However, a generic medicine’s inactive ingredients, name, appearance and packaging can be different from those of the reference medicine. Generic medicines are manufactured according to the same quality standards as all other medicines. A company can only develop a generic medicine for marketing once the period of exclusivity on the reference medicine has expired – usually 10 years from the date of first authorisation.

Specifically, a company producing a generic medicine needs to provide a full dossier on the quality of the medicine. In most cases, it also needs to supply data from a bioequivalence study to show that the generic medicine produces the same levels of the active substance in the animal as the reference medicine (EMA 2012). Once bioequivalence is established, it is assumed that the generic medicine will be as safe and effective as the reference medicine. Bioequivalence studies are only needed for medicines that are absorbed by the body before being released into the bloodstream, such as medicines that are taken by mouth. Generic medicines that are administered directly into the bloodstream (e.g. by intravenous injection) do not need to be tested for bioequivalence against the reference medicine.

Once the generic medicine is authorised, the same information appears in the ‘product information’ of the generic medicine (the summary of product characteristics [SPC], the labelling and the package leaflet) as in that for the reference medicine, except for differences relating to inactive ingredients (excipients) and any patented indications. The safety of generic medicines is monitored in the same way as for branded medicines (EMA 2012). Veterinary generics are usually branded, for example, Milbemax, containing the active ingredients milbemycin oxime and praziquantel, is the original, and Milbactor and Milprazon are generic versions containing the same active ingredients.

Authorisations are issued to companies once they have demonstrated that the product is of the appropriate quality, can be used safely and will be effective when used in accordance with the product information. In deciding whether to licence a new treatment, the regulatory authority must judge whether the benefits outweigh the associated risks and decide whether the adverse effects are acceptable. The benefit-risk evaluation in the context of a new medicinal product application takes into account the conclusions of the different parts of the dossier submitted. For veterinary medicines, because of a lack of data, benefit-risk evaluation currently relies mainly on a qualitative approach. The EMA has said that, because of this, expert judgement remains the cornerstone of benefit-risk evaluation for the authorisation of veterinary medicines. (EMA 2009) 

For example, grapiprant (Galliprant) was granted a centralised licence on the basis of two placebo-controlled field studies (in a total of 616 dogs). Based on the safety submission, it was deemed to be generally well tolerated in dogs at the licensed dose. The most severe risk to humans – accidental ingestion by a child – required the SPC to include an appropriate warning and the product to be marketed in child-resistant packages. Based on the data presented, the overall benefit-risk was considered positive. (EMA CVMP 2017). In another example, imepitoin (Pexion) for the treatment of idiopathic epilepsy, three out of 27 members of the European committee that assessed imepitoin disagreed with the decision to grant it a marketing authorisation. This was because they judged that the possible better tolerability of imepitoin compared with phenobarbital was outweighed by the lack of demonstration of efficacy of imepitoin and the possibility of worsening of epilepsy in some dogs. The wording of its SPC reflects this, stating that there is variable efficacy: “some dogs will be free of seizures, in other dogs a reduction of the number of seizures will be observed, whilst others may be non-responders. In non-responders, an increase in seizure frequency may be observed” and recommends “use after careful evaluation of alternative treatment options”. (EMA CVMP 2012) (Related modules: Grapiprant; Imepitoin for idiopathic epilepsy in dogs).

An authorised product has an authorisation number preceded by the symbol Vm on its product literature (e.g. labels). A product with a European authorisation will not have the Vm symbol on its product literature; instead it carries an identifier with the following format - EU/2/01/011/001.

The regulatory authority also decides the legal status of the product. This determines the route by which the product can be supplied. There are four supply categories for veterinary medicines in the UK (VMD December 2018a)

  • Prescription Only Medicine–Veterinarian (POM-V)

  • Prescription Only Medicine–Veterinarian, Pharmacist, Suitably Qualified Person (POM-VPS)

  • Non-Food Animal–Veterinarian, Pharmacist, Suitably QualifiedPerson (NFA-VPS)

  • Authorised Veterinary Medicine–General Sales List (AVM-GSL)

Veterinary surgeons, pharmacists and Suitably Qualified Persons (SQPs), collectively known as Registered Qualified persons, are entitled to prescribe veterinary medicinal products. They may only prescribe and/or supply the products that fall within the scope of the qualification and the registration they hold. The VMD website (product information database) includes a list of products authorised in the UK (around 2,700 in total) and indicates the legal supply category for each.

A marketing authorisation must be renewed 5 years after initial authorisation to remain valid. Once renewed, the authorisation is valid indefinitely unless, within 5 years of the renewal, the regulator notifies the marketing authorisation holder, on justified grounds relating to safety, that the authorisation will cease to be valid 5 years from the first renewal unless the holder applies for a further renewal. The further renewal is not time-limited. If it is not renewed, it will no longer be valid and the product may not be marketed. A reassessment looks at all the relevant data available to the VMD to confirm that the benefit:risk balance is favourable. If not, the authorisation may be suspended or expired. Exceptional marketing authorisations are reassessed on an annual basis. (VMD March 2017; VMR 2013)

In addition to the above distribution categories, products may be supplied under the exemption for small pet animals and marketed without a marketing authorisation, subject to certain conditions (VMD December 2018b). The exemption applies to products for:

  • aquarium animals

  • caged birds

  • homing pigeons

  • terrarium animals

  • small rodents

  • ferrets

  • rabbits.

The active ingredient of such a product must be approved by the regulator. Ingredients that are antibacterial, narcotic, psychotropic or that require veterinary control are not permitted. The product must conform to the following criteria:

  • be manufactured in accordance with GMP

  • be labelled correctly and contain a statement to show they are exempt from the statutory requirement for a marketing authorisation

  • be for administration orally or topically or, for fish products, by addition to water.

  • only be sold in pack sizes that are for a single course of treatment.

For medicines licensed under the centralised procedure, the EMA has the responsibility for producing and publishing a European public assessment report (EPAR). This is a full scientific assessment report of the medicine, and also contains a public-friendly overview and the package leaflet. (EMA 2019) Since October 31st 2005, for medicines licensed nationally or for which the UK is the Reference Member State, the VMD has a responsibility to publish a Public Assessment Report (PAR).

All authorised medicines (including generics) have an SPC. This sets out how a medicine should be used, and the effects (including adverse effects) it may have on animals (and on humans and the environment). The VMD product database has links to the SPCs of all veterinary medicines licensed for use in the UK and links to any PARs. For centrally authorised products SPCs and EPARs are obtained via a link to the EMA website.

The SPC is a legal document. It is drafted by the company applying for authorisation to market the medicine, but the wording must be approved by the regulatory authority (the VMD or, for products centrally authorised, the EMA). The SPC is a summary of what has been agreed about the product as a result of the regulatory authority’s assessment, and is based on the clinical trials done during the development of the product. The SPC does not usually give details of the clinical trial evidence of efficacy, but this can be found in the relevant PAR or EPAR, which can be helpful particularly when there is no other published evidence on efficacy. We always look at the relevant PAR or EPAR when reviewing a medicine for Veterinary Prescriber modules.

Clinical trials are usually not large enough to detect all potential adverse effects (particularly rare effects) or to show the true incidence of such effects. Continued monitoring of drug safety after marketing is crucial for detecting adverse effects that have not been picked up in clinical trials, or are specific to certain breeds or groups of animals, and for tracking the incidence of known adverse effects. In the UK, the Suspected Adverse Reactions Surveillance Scheme (SARSS) run by the VMD is used to collect voluntary reports from veterinary professionals, pharmaceutical companies and the general public on suspected adverse reactions to veterinary medicines. The scheme collects reports on licensed and unlicensed veterinary medicines, and human medicines used in animals, including: 

  • those occurring after authorised or unauthorised use

  • those associated with suspected lack of efficacy

  • human reactions to veterinary medicines

  • antibacterial residues in milk, meat or eggs

  • environmental problems.

The Royal College of Veterinary Surgeons considers it to be part of a veterinary surgeon’s professional responsibility to the general public to report suspected adverse events, even though it is voluntary. Pharmacists and SQPs should also record and report adverse events. Suspected adverse events can be reported to the VMD or to the marketing authorisation holder (MAH) of a veterinary medicine. The MAH is required to record, and report all adverse events (from anywhere in the world) that they are aware of to the regulatory authority, and monitor for trends that may suggest a safety issue. Also, the MAH must report all suspected adverse events in Periodic Safety Update Reports submitted to the VMD at specified intervals (VMD April 2016). The VMD also encourages vets to report adverse events to medicines prescribed under the Cascade.

Advice on how to report a suspected adverse event can be found on the VMD website. (VMD January 2019) Reports can be filed using the VMD’s online reporting site. Forms can also be downloaded and printed off from the VMD website. Alternatively contact the VMD on 01932 338427 or adverse.events@vmd.defra.gsi.gov.uk.

All reports received by the VMD are recorded on a database, and all are acknowledged. Further information, such as post-mortem reports or laboratory results, may be requested to help determine whether there is a causal relationship between the product and the reported adverse event. Single reports do not usually result in action by the VMD. However, if a pattern of adverse events for a specific product emerges, regulatory actions to improve the safety of that product are taken depending on how serious they are. Such actions include:

  • addition of warnings to the product information

  • changes in the authorised use of the product

  • product or batch recall

  • suspension of the product from the market until the safety issues are resolved

  • suspension of the right to manufacture the product.

Feedback from SARSS comes through a report, published annually in the Veterinary Record.

For example, after receiving reports of seizures with Bravecto (fluralaner), the EMA concluded in July 2017 that the medicine continues to have an acceptable safety profile. However, the company that markets the product was told to update the package leaflet (within 6 months) and include seizures as a new side effect that is reported very rarely (that is, in less than one animal out of 10,000 animals treated). Vets and pet owners have also been advised to use Bravecto with caution in dogs with epilepsy. (EMA August 2017)

Veterinary medicines (brands and generics) marketed in the UK must have a marketing authorisation from the regulatory authority (either the Veterinary Medicines Directorate or European Medicines Agency) or be marketed under the terms of the exemption for small pet animals. It is not yet clear how the outcome of Brexit will affect this, if at all. Ultimately, the regulatory authority must decide whether the benefits of a medicine outweigh the associated risks, and decide whether the adverse effects are acceptable before granting an authorisation. At the time of licensing, full information about the adverse effects cannot be known and so continued monitoring of the safety of authorised medicines is crucial.

PODCAST

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.

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How we produced this module

Our modules start with a detailed outline and electronic literature search. We then commission a collaborating author to draft the text of the module. The collaborating author on this module was Helen Barnett. The draft is circulated unsigned to a wide range of commentators, including practising first-opinion vets, 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. 

References

Department for Environment Food & Rural Affairs. Regulation of veterinary medicines if there’s no Brexit deal. September 2018 [online]. Available: https://www.gov.uk/government/publications/regulation-of-veterinary-medicines-if-theres-no-brexit-deal/regulation-of-veterinary-medicines-if-theres-no-brexit-deal. [Accessed 10.1.19] 

European Medicines Agency. Download medicine data. January 2019 [online]. https://www.ema.europa.eu/en/medicines/download-medicine-data#european-public-assessment-reports-(epar)-section [Accessed February 2019] 

European Medicines Agency. Committee for Medicinal Products for Veterinary Use. CVMP assessment report for Galliprant. 2017 [online] https://www.ema.europa.eu/documents/assessment-report/galliprant-epar-public-assessment-report_en.pdf. [Accessed January 2019] [EPAR]

European Medicines Agency. CVMP assessment report for Pexion, 2012. https://www.ema.europa.eu/en/documents/assessment-report/pexion-epar-public-assessment-report_en.pdf . [Accessed March 2019]

European Medicines Agency. Tick and flea control agent Bravecto continues to be acceptably safe to use. August 2017 [online]. Available: https://www.ema.europa.eu/en/news/tick-flea-control-agent-bravecto-continues-be-acceptably-safe-use [Accessed 17.1.19] 

European Medicines Agency. Guideline for the conduct of efficacy studies for non-steroidal anti-inflammatory drugs. January 2014 [online]. Available: https://www.ema.europa.eu/documents/scientific-guideline/guideline-conduct-efficacy-studies-non-steroidal-anti-inflammatory-drugs_en.pdf. [Accessed 10.1.19] 

European Medicines Agency. Questions and answers on generic medicines, 2012 [online]. Available: http://www.ema.europa.eu/docs/en_GB/document_library/Medicine_QA/2009/11/WC500012382.pdf [Accessed 10.1.19] 

European Medicines Agency. Recommendation on the evaluation of the benefit-risk balance of veterinary medical products. April 2009 [online]. Available: https://www.ema.europa.eu/documents/other/recommendation-evaluation-benefit-risk-balance-veterinary-medicinal-products_en.pdf. [Accessed 10.1.19]

Murphy D. Environmental risk assessment of veterinary medicines. Vet Record. December 2018. 

The Veterinary Medicines Regulations. 2013 [online] http://www.legislation.gov.uk/uksi/2013/2033/contents/made. [Accessed 10.1.19] 

Veterinary Medicines Directorate. Report a suspected problem with an animal medicine or microchip . January 2019 [online]. Available: https://www.gov.uk/report-veterinary-medicine-problem [Accessed 17.1.19] 

Veterinary Medicines Directorate. Product Information Database, 2019 [online]. Available: https://www.vmd.defra.gov.uk/ProductInformationDatabase/Default.aspx. {Accessed 10.1.19] 

Veterinary Medicines Directorate. Retail of veterinary medicines Last updated December 2018a [online]. Available:https://www.gov.uk/guidance/retail-of-veterinary-medicines. [Accessed 10.1.19] 

Veterinary Medicines Directorate. Exemption from authorisation for medicines for small pet animals. Last updated December 2018b [online]. Available:https://www.gov.uk/guidance/exemption-from-authorisation-for-medicines-for-small-pet-animals. [Accessed 10.1.19] 

Veterinary Medicines Directorate. Marketing authorisations for veterinary medicines. Last updated November 2018 [online]. https://www.gov.uk/guidance/marketing-authorisations-for-veterinary-medicines. [Accessed 10.1.19] 

Veterinary Medicines Directorate. Legal controls on veterinary medicines. Last updated July 2018 [online]. Available:https://www.gov.uk/guidance/legal-controls-on-veterinary-medicines#requirement-for-a-marketing-authorisation-ma [Accessed 10.1.19] 

Veterinary Medicines Directorate. Apply to renew a marketing authorisation for a veterinary medicine. Last updated March 2017 [online]. Available: https://www.gov.uk/guidance/apply-to-renew-a-marketing-authorisation-for-a-veterinary-medicine. [Accessed 10.1.19] 

Veterinary Medicines Directorate. Veterinary pharmacovigilance: your responsibilities. Last updated April 2016 [online]. Available:https://www.gov.uk/guidance/veterinary-pharmacovigilance-your-responsibilities. [Accessed 10.1.19] 

Veterinary Medicines Directorate. VMD statement on veterinary medicinal products containing cannabidiol September 2018 [online]. Available: https://www.gov.uk/government/news/vmd-statement-on-veterinary-medicinal-products-containing-cannabidiol. {Accessed 5.03.19]