K9 Advantix flea, tick & mosquito topical for Large Dogs 21–55 lb — 4-Month, vet-recommended, waterproof

K9 Advantix II Large Dog is a monthly topical treatment that kills and repels fleas, ticks, mosquitoes, biting flies and lice for dogs 21–55 lbs.

Designed as a vet-recommended spot-on solution, this fragrance-free formula delivers fast, water-resistant protection after a single application. It works on contact to reduce flea reproduction and begins eliminating fleas quickly, while also providing repellency against mosquitoes and ticks. Available over the counter in multi-dose packs, K9 Advantix II makes routine parasite protection simple and convenient.

How quickly does K9 Advantix II begin protecting my dog?

The formula starts acting soon after application and can kill fleas within 12 hours of the first treatment. It also repels and kills ticks and mosquitoes on contact, helping reduce the chance of bites shortly after drying. For consistent coverage, apply once every 30 days as directed on the label.

• Kills fleas within 12 hours of initial application
• Repels and kills ticks and mosquitoes on contact
• Waterproof after 24 hours so protection continues after brief swims or baths
• Monthly reapplication maintains continuous defense

Will this prevent a flea infestation in my home?

K9 Advantix II reduces the flea life cycle by killing adult fleas on contact before they can lay eggs. By removing adult breeders from your pet, it helps limit new eggs entering your environment, which is an important step in stopping household infestations. For best results, combine pet treatment with cleaning measures at home.

• Kills adult fleas to help prevent egg-laying
• Reduces risk of flea-related skin irritation when used monthly
• Works with home cleaning (vacuuming, washing bedding) for faster control
• Available in 2-, 4- and 6-dose packs to maintain uninterrupted protection

How do I apply K9 Advantix II safely to my dog?

Application is simple: part the hair at the base of the neck and apply the topical solution directly to the skin. Keep the applicator away from the dog’s eyes and mouth and do not allow other pets to groom the application site until it dries. Always read and follow the product label for dosing, age and weight requirements and possible side effects.

• Spot-on tube for quick, mess-free application
• Apply at the base of the neck — avoid eyes and mouth
• Suitable for dogs 7 weeks and older weighing 21–55 lbs
• Check label for warnings and follow reapplication schedule

Is K9 Advantix II the right choice for my dog's lifestyle?

This topical treatment suits both indoor and outdoor dogs that need broad-spectrum parasite defense. It’s fragrance-free and becomes waterproof after 24 hours, so it works for active dogs that play outside or enjoy occasional swims. Because it is available without a prescription, you can easily keep up monthly protection year-round.

• Recommended for active indoor and outdoor dogs
• Fragrance-free formula for sensitive noses
• Waterproof after 24 hours, ideal for outdoor activity
• OTC availability and multi-dose packs for convenience

Who is this for: K9 Advantix II Large Dog is intended for dog owners seeking a straightforward, monthly topical that kills and repels multiple external parasites for dogs weighing 21–55 pounds. It’s a good option for families who want fast-acting protection without a prescription, for dogs at least 7 weeks old, and for households aiming to minimize flea reproduction and outdoor pest exposure. Always consult the label or your veterinarian if your dog has health concerns, is pregnant, or is on other medications.

Ingredients

Imidacloprid, Permethrin, Pyriproxyfen