Can I use 5lb cat flea medicine on my 7lb cat safely and effectively?

You can use Advantage spot on but you will need the two different sizes (for small cats and for large cats), you won't find any reliable and safe treatment that would treat a 2 pound cat as well as a 20 pound cat, there is no such thing.

Hi there, and thank you for posting this question. I think the answer depends on the exact medication and what the margin of safety is for that particular medication. Most likely it would be fine as the weight is so close, but I would want to know what medication it was and then overdose concerns as well as what the margin of safety is. All of this information should be in the package insert. Best of luck and thank you for using Pet Coach.

Hi there! I hate to disagree with your veterinarian - but personally, I never recommend underdosing pets with flea/heartworm medication, as this can cause the meds to not be effective. In fact, it's recommended to round up to the next higher weight range if there is any doubt about which one the pet fits into, or if their weight is borderline. This is because these meds have a very high margin of safety, so the risks of underdosing are much greater. For this reason, personally, I would use the higher weight range for your 10+ lb kitty unless your vet has a specific reason not to recommend this in her case. Advantage Multi, like Revolution, is absorbed internally - this is how it's able to treat intestinal parasites and prevent heartworm disease. There is no problem with using either of these monthly long-term, as they're both extremely safe medications in cats :)

This is because the active ingredient amount is weight dependent. A bigger pet needs more of the active ingredient to kill the fleas than a smaller pet. It's fine to use these on your pets this month and next month. If they are close to a year old, they will not grow much bigger. I hope this helps!

Thanks for using Petco Pet Education Center, formerly Petcoach! You are correct- Cody will need the 560mg size. It won’t hurt to give the smaller size but it may not be totally effective. Or you can contact your veterinarian and see if you can switch out the dose for the correct size. Good luck and kisses to Cody!

It did not work since you underdosed it significantly, ie you should have applied the respective flea medicine for the weight of your cats. I suggest you get the proper size flea preventive and apply it again now.

I would not recommend it as the doses are specifically formulated for weight and species. There is no way to really know how much medication you are giving. In my experience, cats tend to react much worse when the wrong dosage is given. I would be very leary of an online chart for adjusting dosages, unless it comes directly from the manufacturer, which I highly doubt that it does. You can also try checking with local shelters and veterinary clinics that may be willing to donate some products. It's worth a try to ask. I hope this helps, best of luck!