Antibiotic Course Duration

Welcome to the Bova UK Podcast, where we discuss diseases from diagnosis through to management. These podcasts are aimed at registered vets and veterinary nurses. If you’re listening as a pet owner, we always advise that if you have any concerns about your animal, please consult your local veterinary surgeon.

Host:

So for today’s podcast, we have Fergus Allerton back with us to discuss antibiotic course durations and their significance.

For those who don’t know Fergus, he graduated from the University of Bristol and completed a residency in internal medicine at the University of Liège in Belgium. He’s also a diplomate of the European College of Veterinary Internal Medicine and the current editor of Companion and the BSAVA Formulary. Fergus is actively involved in veterinary antibiotic stewardship and contributed to the development of the PROTECT ME guidelines—with a new version launching very soon.

He’s also working within the European Network for Optimization of Veterinary Antimicrobial Treatment, developing recommendations for antibiotic use in surgical prophylaxis.

So, welcome Fergus, and thank you so much for taking the time to join us today—you’re clearly keeping yourself very busy!

Fergus:

It’s brilliant to be here again, and I’m looking forward to it because I think antibiotic courses are something we’ll hopefully be able to answer even better in a few years’ time.

Host:

Yes, absolutely. We’re thrilled to have you back. In today’s episode, we’ll be specifically discussing the importance of antibiotic course duration—how it’s decided—and a current study that vets can actively take part in.

It’s a small topic within the wider issue of antimicrobial resistance, but one of significant importance. So, Fergus, could you start by telling us: what is the basis for current antibiotic course durations in dogs and cats?

Fergus:

Well, unfortunately, a lot of it is somewhat arbitrary. Often we just reach for a familiar number—maybe the pack size. There are ten tablets, so we prescribe ten tablets, whether that equates to five or ten days. Sometimes it’s just easier to say, “We’ll give a week or two weeks’ worth.”

These durations often have little to do with the actual bacterial condition we’re trying to treat. Ideally, we should be asking: what is the optimal course duration for each specific indication? Should we stop when the animal is better, or when there’s a confirmed bacteriological cure—and are those two endpoints even the same?

At the moment, most recommendations are empiric—they’re based on tradition or consensus rather than strong evidence. But the hope is that we can shorten courses and back that decision with evidence that gives us confidence the treatment is effective.

Host:

Can we infer anything from human medicine in terms of their evidence base? Could that be applied to veterinary medicine?

Fergus:

I think so, yes. Human medicine went through the same process—initially prescribing arbitrary course lengths. We all remember being told, “Always finish the course,” which made it feel like the doctor had precisely tailored it for you. That’s changing now.

In human medicine, they’re moving towards “treat until you’re better,” and trying to determine how long that really is. Some people recover before finishing the course. In fact, this ties nicely into our previous podcast where we discussed the Antibiotic Amnesty—returning unused antibiotics instead of keeping or discarding them unsafely.

There’s excellent work by Brad Spellberg in the US. He compiled all the randomised controlled trials comparing short versus long antibiotic courses across conditions like pyelonephritis, osteomyelitis, septic arthritis, and community-acquired pneumonia. In every case, shorter courses had the same outcomes as longer ones—and fewer antibiotics used means less resistance.

If this holds true for people, surely it could be true for cats and dogs too.

Host:

That makes sense. But would we need our own evidence in veterinary medicine, or can we use human studies?

Fergus:

The message is definitely worth considering, but yes, we need to generate our own data. Unfortunately, there aren’t many randomised controlled trials in veterinary medicine specifically focused on antibiotic durations.

We need to start building that evidence base. We need to show that shorter courses are not inferior—and that they’re effective. That reassurance will encourage more vets to adopt them.

Host:

You briefly mentioned that we shouldn’t always encourage finishing every course. As a veterinary nurse, we’re taught to educate owners on this. So when is it appropriate not to finish the course?

Fergus:

This really comes down to clinical judgement. Ideally, we shouldn’t prescribe overly long courses to begin with. But in some chronic cases—like cholangitis in cats or dogs—it might be reasonable to review after a week and then decide whether to extend or stop.

A review phase is critical in any extended course. Conditions like pyoderma, for example, often require longer treatment if there’s an underlying cause, but again, that needs regular assessment and veterinary oversight.

In human hospitals, because patients are often cared for by multiple doctors, they’ve implemented “continuation reviews” at set points. Rather than asking “Should I stop?”, they ask “Should I continue?” It changes the mindset and may be a useful approach in veterinary practice too.

Host:

Yes, I see. And I assume culture and sensitivity testing also helps decide whether or not to continue?

Fergus:

Absolutely. I’m a big fan of cytology and culture—especially to confirm a true infection and not just a commensal organism. Monitoring can also help determine whether we’ve achieved a bacteriological cure.

And if the pet is improving clinically, that’s often more important than an AST result alone. Some research from Copenhagen, by Luca Guardabasi, showed that even MRSP infections sometimes respond to beta-lactams in vivo, despite lab results suggesting otherwise. So always consider the patient in front of you.

Host:

So why is course duration so important, especially during AMR Awareness Week?

Fergus:

Because more antibiotic use means more resistance. Prescribing for two weeks when one week is enough leads to unnecessary exposure—not just to target bacteria, but to the pet’s entire microbiome. Resistance can develop in the gut flora, and pets can share resistant bacteria with humans.

We’re talking about MRSA in humans, MRSP in pets, and resistant strains of E. coli. It’s a real public health concern.

Host:

You’ve spoken about some pretty alarming statistics in the past. What are we facing in the years ahead?

Fergus:

Antibiotics have saved countless lives. But if they stop working, we’ll lose the ability to perform many life-saving procedures—chemotherapy, joint replacements, even routine surgeries.

If every chemo patient faced a deadly multi-drug-resistant infection, we simply wouldn’t give chemo anymore. We could see 10 million people a year dying from AMR by 2050, especially in low- and middle-income countries.

Veterinary professionals are part of this ecosystem. By prescribing responsibly, we’re contributing to the solution. And when we tell owners, “Your dog doesn’t need antibiotics for this,” it reinforces the same message they may be hearing from their doctor. That matters.

Host:

Absolutely. So, how do we build that veterinary evidence base? What can vets do?

Fergus:

In the UK, we’ve launched a study called the Stop on Sunday Trial. We’re trying to determine the optimal antibiotic duration for treating sporadic cystitis in female dogs—conditions that genuinely require antibiotics.

It’s a common presentation, and we’re asking vets to prescribe amoxiclav so the course ends on a Sunday. If the dog comes in Monday, that’s 7 days; Wednesday, 5 days; Friday, 3 days. It allows us to collect real-world data on course duration and outcomes.

We’re using a secure platform called Castor to capture the data, and we just need a few minutes of your time to input case details. No additional diagnostics or procedures are required.

Host:

That sounds incredibly manageable. And what should a vet expect to do?

Fergus:

It’s about a two-minute commitment per case. You need to:

• Decide if it’s a female dog with sporadic cystitis.
• Prescribe amoxiclav with the course ending Sunday.
• Get the owner’s consent and email.
• Enter the data into Castor the same day.

We’ve published the study protocol for transparency, and everything is fully GDPR compliant. But we need more participants—if every signed-up vet provided just 2–3 cases, we’d have enough data.

Host:

It’s an exciting opportunity to contribute to something that could really shape future prescribing practices. We’ll include all the necessary links and contact info for anyone wanting to join the study.

Fergus:

Thank you. I’m grateful to the vets already participating. If anyone’s interested in helping with data analysis or publication later on, we’d love to hear from you.

Host:

Thank you so much for your time, Fergus. It’s been lovely chatting with you, and best of luck with the study. We’re really excited to see where it goes!

Fergus:

Thanks very much. Take care.