Switching dog flea treatment: tablet to spot-on

Switching from an oral flea tablet to a spot-on is straightforward, but timing matters — you want to avoid a gap in cover without doubling up and over-treating. Before I give you the specifics, a couple of quick questions: which oral tablet has your Rottweiler been on, and when was the last dose? Also, how heavy is he or she roughly — Rottweilers vary quite a bit, and spot-ons are dosed by weight.

Good — that timing actually works in your favour. NexGard gives 4 weeks of cover per tablet, so at three weeks post-dose she still has roughly a week of protection left. That means you can apply a spot-on in the next 7 days and transition cleanly with no gap and no overlap worth worrying about. At 42kg she's solidly in the large-dog bracket for spot-on dosing. Can I ask — are you happy applying a spot-on monthly, and is there any reason you're set on spot-on specifically, or would a longer-acting option interest you?

Woodland walks make tick cover genuinely important, so I'd steer you toward Frontline Plus for Dogs (large dog, 20–40kg) — except at 42kg your Rottweiler sits just above that band, so you'll need the extra-large version, which covers dogs 40–60kg. Frontline Plus contains fipronil and (S)-methoprene, which kills adult fleas, flea eggs, and flea larvae, and it's also licensed for ticks and lice. It's one of the most consistently reliable over-the-counter spot-ons available, it's widely stocked on Amazon UK, and at her weight you're using one pipette per month. Apply it to the skin between the shoulder blades — part the fur fully so it hits skin, not coat. Because her last NexGard was three weeks ago, apply the Frontline Plus within the next 5–7 days to keep cover continuous.

Since you're not seeing fleas right now, you don't need to treat the home urgently — but it's worth knowing that 95% of the flea lifecycle lives in the environment, not on the dog. Flea eggs shed from pets can lie dormant in carpets and bedding for months. A sensible habit is to use a household flea spray like Indorex or RIP Fleas once or twice a year as a preventive measure — hoover thoroughly first, treat carpets and soft furnishings, and let it dry. It's much easier than dealing with an outbreak. For now though, just get the Frontline Plus applied this week and you're in good shape.

Great choice. Just to recap: apply within the next 5–7 days to bridge cleanly from the NexGard, use the 40–60kg pipette, and part the fur properly so it reaches skin. After that, same day each month. If you ever do see fleas, hit the house with Indorex at the same time — that combination is what actually clears an infestation properly. Good luck with her.