VMD Voices: Our Experts Explain
Welcome to the third blog in our 'VMD Voices: Our Experts Explain' series. In this series, you'll hear from specialists across the Veterinary Medicines Directorate (VMD), from scientists and vets to enforcement and intelligence officers.
In this blog, we hear from Aaron Rush, head of the VMD’s Pharmaceutical Quality Team about how complying with the broach limits and expiry dates of medicines plays a key role in protecting animal health and welfare.
About Author
I graduated from the University of Reading in 2017 with a degree in Chemistry. After working in the petrochemical industry as an analytical chemist, I joined the Veterinary Medicines Directorate (VMD) as a junior assessor within the Pharmaceutical Quality team. Since then, I have progressed to head of team, leading a group of assessors responsible for the evaluation of data relating to the chemistry, manufacture and control (CMC) of pharmaceutical products. These include product defect reports, animal test certificates (ATCs), specific batch controls (SBCs), marketing authorisation applications (MAAs), and variations to existing authorisations.
When veterinary medicines aren't used correctly, the risks can be wide-ranging and can directly impact animal health, your professional reputation and compliance with the law. Two issues in particular continue to surface in our inspections: in-use shelf life and expired medicines. Both can be simple to manage, yet the consequences of getting them wrong can be serious
Stability: What is stability?
Credit: PixelbayStability describes a pharmaceutical product’s ability to maintain chemical identity, purity, strength, and performance over time. A loss of stability occurs when the active pharmaceutical ingredient degrades, or when the product no longer performs as intended. This can occur in several ways, including:
The active pharmaceutical ingredient undergoing partial or complete transformation into different chemical entities Degradation of the product’s key quality standards - for example, tablets exposed to moisture may not de-blister, divide or dissolve properly when taken Microbiological or physical contamination of the product arising from exposure to the environmentThe most common causes of degradation are from exposure to heat, light, moisture or air. The risk of exposure to each of these is clearly increased once a product has been opened or broached. Opened products are also significantly more susceptible to microbiological contamination, which is of particular concern for parenteral products such as solutions for injection.
In-use shelf-life and broach limits: are you checking them?
So, what exactly is an in-use shelf life? The in-use shelf life is the period that a product can safely be used after first opening. This period is proposed by the manufacturer and is scientifically assessed by the VMD as part of the authorisation process. The moment a product is opened or broached, the stability clock starts ticking.
There is no mandatory minimum or maximum in-use shelf life stipulated by the VMD; typically, medicines will have an in-use shelf life of 28 days, but this may be shorter or longer depending on the intended use of the product, and the data presented by the manufacturer during assessment.
Broach limits describe something a little different; namely, the number of times a container can safely be pierced, or broached. If a product is broached in excess of this limit, it is unlikely that the integrity of the closure (e.g., rubber stopper) will be maintained, leading to exposure of the product within to contamination, air, moisture, etc.
Credit: PixelbayYou can find both the in-use shelf-life and, where relevant, the broach limit in each product’s Summary of Product Characteristics (SPC) and Package Leaflet via the VMD’s Product Information Database.
Importantly, broach limits are only described where a container could theoretically be broached, based on the recommendations in the SPC, more times than has been demonstrated as safe. This means that even when used according to the authorised instructions for use, it is possible that a container may reach its broach limit before the product reaches the end of its in-use shelf life.
The absence of a broach limit should be taken into consideration when using medicines ‘off-label’ via the prescribing cascade. Off-label use may result in a container being broached more times than anticipated during its authorisation, so extra care should be taken.
To provide context, during routine inspections of veterinary practice premises (VPPs), VMD inspectors found that 18% of practices (i.e., nearly one in five) inspected between October and November 2025 were using medicines beyond their in-use shelf life.
Single-use products, such as those presented in glass ampoules, will have no stated in-use shelf life, as they are only designed and authorised to be used immediately after the container is opened. After the first use of any such product, the container, and any remaining product therein, should be disposed of.
Exceeding either the in-use shelf life or the broach limit means that you can no longer rely on the product to be safe, stable, or effective. That means:
The active ingredients may have degraded The formulation may no longer have the same properties (either before or after administration) The product could have become contaminated – either physical contaminants through degradation of the container closure, or microbiological contaminants through interaction with the environmentCrucially, using a medicine beyond its in-use shelf-life isn’t just risky - it’s an offence under the Veterinary Medicines Regulations 2013, as amended (VMR). It would mean treating an animal with a product that is no longer the medicine you think it is. You would effectively be administering an unknown substance with unknown potency and an unknown safety profile.
Thankfully, there is a simple solution: always record either the opening date or the use by date on the packaging as soon as you broach a product. If you can’t establish the date the container was first broached, do not guess – do not use it.
A simple tip for practices: consider applying a system for checking that every opened product has recorded opening date on its packaging, such as daily checks. If you check at the end of each day and a bottle doesn’t have a date on it, then you could be confident the bottle was broached that day, and record the date accordingly. This simple habit can you help you prevent broaching medicines beyond their limit.
To stay compliant:
Check the broach limit before each use. Label every product clearly with the date when first opened, or when it needs to be used by. Don’t use the product if you’re unsure whether it remains within its in-use-shelf life.By staying compliant you are helping to protect animal welfare and keeping the public and our environment safe.
Why expired medicines should never be used
Credit: PixelbayIn-use shelf life and broach limits are one half of the picture. Expiry dates are the other. Whereas the in-use shelf life manages stability after opening, expiry dates reflect how long a product can be safely stored before it is opened.
The expiry date isn’t a suggestion or a guideline: it’s the point at which the manufacturer, and in turn the regulator, can no longer guarantee stability, and therefore, safety or efficacy of a given product.
Using an expired medicine is:
Illegal under the VMR A breach of the RCVS Code of Professional Conduct Potentially dangerous for the animals and humans involved, as well as the environmentHere’s what can happen when expired medicines are used:
1. Reduced or total loss of efficacy
Medicines can lose potency over time. In conditions requiring precise, reliable dosing - such as epilepsy, heart disease, or diabetes - reduced efficacy can put an animal's life at risk.
2. Increased antimicrobial resistance
Expired antimicrobials may not fully clear infection. Sub‑therapeutic dosing is a recognised driver of resistance to antimicrobials, undermining the profession’s efforts to preserve the effectiveness of these medicines.
3. Formation of harmful breakdown products
Some medicines may degrade into potentially harmful compounds.
4. Less effective preservatives
Injectables, eye drops, creams, and many other multidose products often rely on preservatives to prevent microbial contamination. Once those preservatives degrade, bacteria and fungi can grow – increasing the risk of infection if the expired product were to be administered.
Once the packaging has been opened, exposure to air and humidity can speed up degradation even further. This is why in-use shelf life, broach limits, and expiry dates work together as part of the same safety framework.
Overall, expiry dates aren’t just red tape - they’re essential for protecting:
Animal health Food safety (in the case of food-producing animals) Long-term effectiveness of medicines such as antibioticsUsing medicines within their recommended timeframes ensures every dose administered is safe and effective, whether you are a veterinary professional or an animal owner managing your animal's care at home.
A shared responsibility
Veterinary practice is demanding, and it’s easy for details like dates and labels to slip through the cracks. But the points described above take seconds to check - and the consequences of overlooking them can be significant. Staying on top of broach limits and expiry dates protects animals, supports professional standards, and keeps you compliant with the law.
If you have any questions, further information is available on the Registration and inspection of veterinary practice premises and Retail of veterinary medicines GOV.UK pages, or you can contact the VMD.
seen at 14:45, 26 May in Veterinary Medicines Directorate.