TLDR Review: K9 Advantix II for Large Dogs
Published: September 20th, 2025
Pros
- •Effective against fleas, ticks, and mosquitoes without requiring pests to bite.
- •Considered safer than oral medications as it can be washed off if an allergic reaction occurs.
- •Seen as affordable and positively reviewed by some users.
- •Can be applied in small amounts over multiple spots on the dog's back for better distribution.
Cons
- •Can cause adverse reactions such as tingling, redness, itching, and severe allergic responses.
- •Not safe for cats; it is lethal to them.
- •Ineffective in preventing tick and flea infestations for several users, despite previous success.
- •Some dogs experienced discomfort, agitation, and even severe symptoms like seizures and skin irritation.
- •Noticed a decline in product effectiveness, prompting some users to switch brands.
Bottom Line
While Bayer K9 Advantix II offers broad-spectrum pest protection, it's crucial to monitor dogs for any adverse reactions, especially during the drying period after application. Some users report a decrease in effectiveness against fleas and ticks compared to previous batches. If your dog has a history of allergies or sensitivities, it might be wise to consult a vet before use or consider switching to an alternative product that's proven effective, such as a chewable treatment.
Lowest at Amazon
$54.00 at AmazonLowest at any Popular Retailer
$31.98 at 1-800-petmedsWhere to Buy
Prices last updated: September 20th 2025 7:35 pm
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