---
product_id: 267971927
title: "Bayer K9 Advantix II Flea, Tick and Mosquito Prevention for X-Large Dogs, Over 55 lbs"
brand: "k9 advantix"
price: "฿3067"
currency: THB
in_stock: true
reviews_count: 5
category: "K9 Advantix"
url: https://www.desertcart.co.th/products/267971927-bayer-k9-advantix-ii-flea-tick-and-mosquito-prevention-x
store_origin: TH
region: Thailand
---

# For dogs over 55 lbs Waterproof after 24 hours Kills fleas in 12 hours Bayer K9 Advantix II Flea, Tick and Mosquito Prevention for X-Large Dogs, Over 55 lbs

**Brand:** k9 advantix
**Price:** ฿3067
**Availability:** ✅ In Stock

## Summary

> 🐾 Protect your big pup like a pro—because bugs don’t stand a chance!

## Quick Answers

- **What is this?** Bayer K9 Advantix II Flea, Tick and Mosquito Prevention for X-Large Dogs, Over 55 lbs by k9 advantix
- **How much does it cost?** ฿3067 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.co.th](https://www.desertcart.co.th/products/267971927-bayer-k9-advantix-ii-flea-tick-and-mosquito-prevention-x)

## Best For

- k9 advantix enthusiasts

## Why This Product

- Trusted k9 advantix brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **No Prescription Needed:** Convenient OTC availability so you never miss a monthly dose
- • **Rapid Flea Elimination:** Kills fleas within 12 hours to stop infestations fast
- • **All-Season Pest Defense:** Repels and kills fleas, ticks, mosquitoes, biting flies, and lice
- • **Waterproof & Fragrance-Free:** Lasts through water exposure with no overpowering scent
- • **Vet-Recommended & Hassle-Free:** Trusted formula with easy topical application—no pills or collars

## Overview

Bayer K9 Advantix II Extra Large Dog is a vet-recommended, topical flea, tick, mosquito, biting fly, and lice treatment designed for dogs over 55 lbs. It kills fleas within 12 hours and repels multiple pests on contact, preventing infestations without the need for a prescription. Waterproof after 24 hours and fragrance-free, it offers convenient, monthly protection to keep your dog comfortable and pest-free all year round.

## Description

K9 Advantix II Extra Large Dog is the veterinarian-recommended formula that helps defend your dog against five pests: fleas, ticks, mosquitoes, biting flies and lice. And unlike other treatments, K9 Advantix II kills and repels fleas, ticks and mosquitoes. K9 Advantix II topical treatment gets straight to work killing fleas on dogs within 12 hours of initial application. This formula stops existing flea infestations and prevents new ones by killing adult fleas on contact so they can’t lay eggs and they don’t have to bite your dog to die. Fleas, ticks, mosquitoes and other pests not only cause discomfort; they may also transmit disease. Monthly use of K9 Advantix II is important to protect your dog against fleas that may cause transmission of tapeworms. This formula also kills fleas which may cause Flea Allergy Dermatitis and flea bite anemia. That’s why K9 Advantix II Extra Large Dog topical, spot-on formula makes application simple - going on in seconds. It's easier than a flea collar and there are no hard-to-swallow pills. You’ll also love that K9 Advantix II is fragrance-free and waterproof after 24 hours of application. Check the product label for information on application and potential side effects. K9 Advantix II pest protection is effective on both indoor and outdoor dogs. Your dog should be at least 7 weeks old and weigh over 55 lbs. to use K9 Advantix II Extra Large Dog. For the ultimate convenience in care, K9 Advantix II is available over the counter – no prescription needed. And, you can stock up with 2-dose, 4-dose and 6-dose packs so you never miss a monthly treatment. Once K9 Advantix II is applied, your dog is ready to get right back to big-pup cuddles and racing around the park. K9 Advantix II Extra Large Dog is a trademark of Elanco or its affiliates.

Review: This work perfectly for our lab no skin irritation always great
Review: I have bought this product many, many times and will absolutely continue to do so for my girls Ruby and Jade. If you live in Texas, you already know the bugs here don’t play around — especially the mosquitoes. These things keep all the thugs off my dogs. Fleas, ticks, mosquitoes… not today. 🚫 Ruby and Jade have zero issues while using this — no reactions, no irritation, no problems at all. It’s easy to apply, works exactly like it’s supposed to, and gives me peace of mind all summer long when the bugs are at their worst. I’ve tried other products over the years, but I keep coming back to this one because it’s reliable, effective, and consistent. When something works this well and keeps my dogs comfortable and protected, I’m sticking with it. If you’ve got dogs and live in a buggy area (or just want the creepy crawlies evicted), this is a must-have. Ruby and Jade approve 🐾🐾 — and so do I!

## Features

- K9 Advantix II Extra Large Dog 30-day treatment & prevention protects dogs over 55 lbs. from fleas, ticks, mosquitoes, biting flies and lice
- Kills fleas within 12 hours of application
- Vet-recommended formula kills & repels on contact so fleas don’t have to bite your dog to die
- Easy-to-apply topical treatment is fragrance-free and waterproof after 24 hours
- No prescription needed

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B07NX2VWYC |
| Allergen Information | Allergen-Free |
| Best Sellers Rank | #101,745 in Pet Supplies ( See Top 100 in Pet Supplies ) #129 in Dog Flea Drops |
| Breed Recommendation | Extra Large |
| Color | Blue |
| Customer Reviews | 4.3 4.3 out of 5 stars (5,486) |
| Date First Available | 22 March 2019 |
| Item Form | Topical |
| Item Weight | 22.7 g |
| Item model number | 90204386 |
| Number of Items | 1 |
| Pet Life Stage | 7 weeks and older |
| Pet Type | Adult |
| Product Dimensions | 10.8 x 2.22 x 12.07 cm; 22.68 g |
| Quantity | 1 |
| Size | 1 Pack |
| Specific Uses | Parasites |
| Storage Information | Store at temperatures and conditions as indicated on the product label. |
| Volume | 4 Milliliters |
| batteries required | No |

## Product Details

- **Active Ingredients:** Imidacloprid, Permethrin, Pyriproxyfen
- **Brand:** K9 Advantix
- **Item form:** Topical
- **Item weight:** 0.05 Pounds
- **Scent:** Unscented

## Images

![Bayer K9 Advantix II Flea, Tick and Mosquito Prevention for X-Large Dogs, Over 55 lbs - Image 1](https://m.media-amazon.com/images/I/71TmwfTVSuL.jpg)
![Bayer K9 Advantix II Flea, Tick and Mosquito Prevention for X-Large Dogs, Over 55 lbs - Image 2](https://m.media-amazon.com/images/I/91srvqROkyL.jpg)
![Bayer K9 Advantix II Flea, Tick and Mosquito Prevention for X-Large Dogs, Over 55 lbs - Image 3](https://m.media-amazon.com/images/I/81EDjQqM2WL.jpg)
![Bayer K9 Advantix II Flea, Tick and Mosquito Prevention for X-Large Dogs, Over 55 lbs - Image 4](https://m.media-amazon.com/images/I/81lc7ZPFGHL.jpg)
![Bayer K9 Advantix II Flea, Tick and Mosquito Prevention for X-Large Dogs, Over 55 lbs - Image 5](https://m.media-amazon.com/images/I/71tUbLQ4DWL.jpg)

## Questions & Answers

**Q: Has anyone switched over from Frontline Plus to K9 Advantix II and is happy? For Dogs**
A: YES!!!!  I've had the same experience with my dogs as Nicole A replied.  I had been pleased with Frontline for years....but in 2012 (and ever since) it has just stopped working.  One of my dogs is a fur-making machine: and fleas don't seem to bother him...even if I am finding them on him.  The other dog has horrible flea allergies:  has immediate, sustained, and severe "hot spots" after even just ONE flea bite...skin will turn pink all over his body...and he "blows" large amounts of his beautiful, lush, scruffy coat...and he just doesn't seem to be his usual happy, bright, and enthusiastic self :-(   Using Advantix II....he seems to not have problems at all (it keeps the fleas from breeding...although if one occasional transient flea bites him....it will die...but the dog will still get a "hotspot", but nowhere as intense or sustained as without Advantix II...and if I find it quickly and clean it with vinegar, he may not even need a dose of benedryl).  During the "flea season" since using Advantix II he has been able to keep his lush coat with no problems.....to such an extent that I brought him in to my vet's office just to show the vet how well he was doing one summer (the dog had been so bad the previous summer while using Frontline that I had to take him to the vet for skin reactions, fur loss in large areas of his coat, and a secondary infection from scratching...I had been so discouraged about the flea problems that year while on Frontline that I had been taking the dog daily to the lake so he could swim and drown the damned fleas).  The vet was very pleased with the dog's condition with Advantix II, and had stated he has learned from his patients that they are also seeing less effectiveness with Frontline in recent years.  I won't use anything else but Advantix II during this up-coming flea season.  (although I do also spray his coat/skin with vinegar (mixed 1/2 with water) each day as a flea deterrent...especially if he gets a hotspot...and I add a small amount of vinegar to his food as well........and when he does need a bath:  I use EXTREMELY diluted Dr. Bronner's castile liquid soap in the "EUCALYPTUS" version....the dog tolerates it well...and it seems the scent repels fleas a bit.   I use the soap as well to launder the cover of his dog bed at least weekly).   I know that insects can get resistent to certain pesticides over time....and I suspect that is why Frontline no longer works in our area.....I sure hope it doesn't eventually happen with Advantix II as well....and I hope that producers of flea/tick products for dogs will monitor this situation and re-formulate their products as needed to address the situation--regionally if need be.

**Q: I thought I was ordering Advantage II but by mistake, ordered Advantix II.  What is the difference, and does it work the same?**
A: You can’t use advantix on cats.  sadly because advantix 2 is superior and is the best out there because unlike advantage (and unlike frontline) it repels flies and mosquitoes as well as ticks and fleas.  but it is toxic to cats.  as cats should be indoors only you shouldn’t need tick/mosquito repellent just flea.  DO NOT USE ADVANTIX ON CATS!  It is toxic to them

**Q: What about cats? I used to use Advantix on my cats with no problems, as suggested by my vet to save money. Has the formula changed?**
A: Look at the active ingredients for both the dog & cat formulas; They are exactly the same. Only difference is the dosage size which you can easily look up on the internet & save yourself a ton of money

**Q: Could I use this along with a flea/tick collar?**
A: As a vet tech we say a flea collar is basically worthless..At most may keep fleas off pets head. If you can buy flea collar at store probably won’t work and even the script only work minimal. Stick to topical like frontline plus, advantage, advantix and oral like Capstar. Flea collars are most always a waste of $. To remove fleas fast simply bathe dog and let dog sit in water…drowning fleas and follow up in few hours with topical if bad infestation. Just a flea or 2 I’d still bathe but topical probably enough. All topicals are water resistant after 24hr

## Customer Reviews

### ⭐⭐⭐⭐⭐ Review
*by M***R on 18 February 2026*

This work perfectly for our lab no skin irritation always great

### ⭐⭐⭐⭐⭐ Review
*by D***L on 29 December 2025*

I have bought this product many, many times and will absolutely continue to do so for my girls Ruby and Jade. If you live in Texas, you already know the bugs here don’t play around — especially the mosquitoes. These things keep all the thugs off my dogs. Fleas, ticks, mosquitoes… not today. 🚫 Ruby and Jade have zero issues while using this — no reactions, no irritation, no problems at all. It’s easy to apply, works exactly like it’s supposed to, and gives me peace of mind all summer long when the bugs are at their worst. I’ve tried other products over the years, but I keep coming back to this one because it’s reliable, effective, and consistent. When something works this well and keeps my dogs comfortable and protected, I’m sticking with it. If you’ve got dogs and live in a buggy area (or just want the creepy crawlies evicted), this is a must-have. Ruby and Jade approve 🐾🐾 — and so do I!

### ⭐⭐⭐⭐⭐ Review
*by H***R on 28 January 2026*

My dog sitter recommended for my dog who loves to roll in the grass and kept getting fleas . Works great for the first 3 weeks , the last week fleas showed up again

## Frequently Bought Together

- K9 Advantix II XL Dog Vet-Recommended Flea, Tick & Mosquito Treatment & Prevention | Dogs Over 55 lbs. | 1-Mo Supply
- K9 Advantix II Large Dog Vet-Recommended Flea, Tick & Mosquito Treatment & Prevention | Dogs 21-55 lbs. | 1-Mo Supply
- K9 Advantix II Medium Dog Vet-Recommended Flea, Tick & Mosquito Treatment & Prevention | Dogs 11-20 lbs. | 1-Mo Supply

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*Product available on Desertcart Thailand*
*Store origin: TH*
*Last updated: 2026-02-23*