TL;DR
- • Prescription isoxazoline products (Bravecto, Simparica, NexGard, Credelio) are the most reliable flea & tick killers.
- • Advocate (moxidectin) is the only commonly used product that also covers lungworm — increasingly important in UK dogs.
- • Online + written prescription is typically 30–50% cheaper than buying at the practice.
- • With prescription fees capped at £21 (CMA 2026), the savings start from month one.
What you're actually trying to prevent
- Fleas — bites cause itching, flea allergy dermatitis (FAD) and tapeworm transmission.
- Ticks — vectors of Lyme disease, babesiosis and, since 2016, the UK-emerging tick-borne encephalitis virus.
- Lungworm (Angiostrongylus vasorum) — now endemic in most of the UK; can be fatal.
- Roundworm / tapeworm — public health relevance, especially with children.
Prescription tablets (isoxazolines)
| Product | Cover | Practice price | Online + Rx |
|---|---|---|---|
| Bravecto (12-weekly chew) | Fleas + ticks | £28–£42 | £18–£28 |
| Simparica Trio (monthly) | Fleas + ticks + worms (incl. lungworm) | £14–£22 | £9–£14 |
| NexGard Spectra (monthly) | Fleas + ticks + worms (incl. lungworm) | £14–£22 | £9–£14 |
| Credelio (monthly) | Fleas + ticks | £9–£16 | £6–£11 |
Spot-on treatments
| Product | Cover | Practice | Online + Rx |
|---|---|---|---|
| Advocate (POM-V) | Fleas + worms (incl. lungworm) + mites — NO ticks | £10–£16 | £6–£10 |
| Frontline (OTC) | Fleas + ticks (weakening efficacy in resistant areas) | £6–£11 | £4–£8 |
| Stronghold Plus / Broadline (cats) | Comprehensive cat cover | £12–£18 | £8–£13 |
Which combination should you actually use?
- Dog, all areas of UK: Simparica Trio or NexGard Spectra monthly — single product, covers fleas, ticks and lungworm.
- Dog, low-tick area, owner prefers spot-on: Advocate monthly + Bravecto every 12 weeks for ticks.
- Cat, indoor-only: Broadline or Stronghold Plus quarterly to cover fleas, worms and ear mites.
- Cat, outdoor: monthly broad-spectrum product, plus tick check after long grass.
The £21 prescription cap maths
Take a 20kg dog on Bravecto. Four 12-weekly chews at the practice = ~£140/year. At online prices with a £21 prescription = ~£92/year. Net saving: £48 in year one, £69 a year thereafter (one prescription typically covers 12 months). Multiply that across NSAIDs, allergy meds and worm cover and the savings can exceed £300/year.
Practical tips
- Treat year-round — UK winters no longer kill fleas thanks to central heating.
- Treat every pet in the household simultaneously.
- Wash pet bedding at 60°C and vacuum carpets/sofas when you see fleas — 95% of the burden is in the environment.
- Remove ticks with a proper tick hook; never burn or pull with tweezers.
FAQs
Are isoxazolines safe?
Yes for the vast majority of dogs. They carry a class warning for dogs with a history of seizures — discuss with your vet if relevant.
Why don't supermarket products work as well?
Many use older active ingredients (fipronil) with documented resistance in UK flea populations.
About the data: Prices are typical 2026 UK retail and online-pharmacy quotes. See our prescription fee explainer for the underlying CMA remedy.