Tough on Fleas and Ticks, Yet Gentle on Dogs


This article is sponsored content brought to you by Elanco.

Fleas are an ever-present risk for dogs, but warmer spring weather stimulates a faster completion of their life cycle, allowing a lapse in flea control to turn into a difficult to eradicate flea infestation. And for dog owners on the eastern seaboard, spring marks the peak of the paralysis tick season and the heightened need for tick protection. 

Awareness amongst dog owners of the importance of tick control has never been greater, with recent media coverage on tick-borne diseases. The understanding of the importance of flea control on companion animals, not just in terms of animal welfare, but for human health is growing, as research uncovers more about the risks of zoonotic flea-borne diseases. 

Fortunately, highly effective ectoparasiticides are available in a range of formats and modes of action. Credelio is the latest product to launch and provides another option for dog owners looking for safe and effective flea and tick control. Credelio is a beef-flavoured, monthly, chewable tablet for dogs from 8 weeks and >2.5kg, containing the isoxazoline, lotilaner. Credelio treats and prevents flea infestations, controls FAD and treats and controls ticks including paralysis, brown dog and bush ticks1.

Like all isoxazolines, lotilaner, exists as an equal mixture of two mirror image forms of the molecule, or ‘enantiomers’. It was found that one enantiomer had up to 100 times greater potency against fleas and ticks, and so an additional purification step was included in the manufacturing process to remove the inactive enantiomer2. Consequently, the amount of lotilaner in Credelio could be halved, meaning less active ingredient for dogs to metabolise and/or eliminate, and allowing for the manufacture of a smaller-sized tablet*. Although Credelio tablets are beef-flavoured and readily eaten by most dogs, their small size makes tableting easy and gentle for those fussy dogs. Credelio can be swallowed whole or chewed but must be given with or within 30 minutes of a meal as there is a significant difference in the bioavailability of lotilaner between fed (82%) and unfed (24%) dogs2.

Lotilaner has favourable pharmacokinetics when given to fed dogs, with rapid absorption (TMAX=2 hours) and slow elimination (T½=31 days), reflected in its fast speed of kill against fleas, and its sustained high efficacy against fleas and ticks. Credelio starts killing fleas within just 2 hours of dosing, with 100% of fleas eliminated within 6-12 hours. Reinfesting fleas are eliminated within 4-6 hours, even at the end of the month, so fleas are not given a window to survive long enough to reproduce and lay eggs, perpetuating the flea infestation in a home. This is supported by Australian field studies, with reduction in flea counts of ≥99.8% on day 30 and 100% on day 60 following administration of a single dose of Credelio (day 0) to flea-infested, client-owned dogs (n=63) living in QLD and NSW. In Australian studies, the efficacy against paralysis ticks (I. holocyclus) remained >97%, even 12 weeks after a single dose of Credelio3, highlighting the benefit of the long half-life (T½) of lotilaner. The high, sustained efficacy of Credelio against brown dog ticks (R. sanguineus) has also been repeatedly demonstrated, and in an Australian study the efficacy was ≥98.8% at 48 hours post-treatment and following each re-infestation over 37 days4.

Although Credelio and all systemically-acting isoxazolines are highly effective at killing brown dog ticks (the vectors of Ehrlichia canis), due to their mode of action and speed of kill they cannot block transmission of this bacterium from infected tick to dog. Only tick repellents, like Seresto, that can repel ticks and prevent ticks from biting can protect dogs from ehrlichiosis5, since it can be so rapidly transmitted after tick bite. However, it’s a good recommendation in high-risk areas to use Credelio in conjunction with Seresto, to protect individual dogs and the wider dog population from this deadly tick-borne disease.

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