Capstar for Dogs and Cats is an over-the-counter tablet that's very safe for both dogs and cats as young as four weeks. (Dogs that weigh more than 25 pounds can use a separate formulation, Capstar for Dogs Only.) It kills fleas quickly and without the mess of topical treatments, but it works only on adult fleas. That means you'll probably need a topical treatment -- or repeated doses of Capstar -- to wipe out an infestation.
Kills adult fleas only. Most reviewers, including vets and pet owners, say Capstar for Dogs and Cats works amazingly fast. Many users say they could literally see fleas dropping off their pets in an hour or less. However, others complain that it had no effect on their pets or that it wore off very quickly. Some of these owners may not have realized that Capstar kills only adult fleas and won't stop new ones from appearing. Some owners say they can keep fleas at bay just by repeating the dose of Capstar every week or so, but most owners use Capstar for immediate relief and a topical treatment for long-term control.
Safe for pets and humans. All reviewers agree that Capstar poses virtually no risk to humans. Side effects in pets are also less common, and less severe, than with topical treatments. One vet, reviewing the product at 1800PetMeds.com, says, "I have rarely seen any side effects in my clinical experience in using this product" and notes that it's safe even for pregnant or nursing pets. A few owners note that pets (especially cats) may become hyperactive as the medicine takes effect, possibly because the fleas bite more as they die. Very rare side effects include lethargy, trembling and allergic reactions.
Can be tricky to administer. Some pet owners like the fact that this tablet doesn't create any mess like topical treatments do. Most owners report no problems getting their pets to take Capstar, but a few say that some pets, especially cats, are reluctant to swallow it. Some owners say the easiest method is to put the pill in the pet's food or hide it in a treat such as cheese or peanut butter. One Amazon.com reviewer consulted videos on YouTube and found that "placing the pill with a finger tip at the back of the throat and then closing their mouths" will do the trick.
More than 560 pet owners review Capstar for Dogs and Cats at this online pet pharmacy. Users give Capstar a rating of 4.2 stars out of 5 overall, with 4.2 stars for effectiveness and 4.5 for ease of use. Most owners say it works fast, with no adverse effects.
Review: Capstar Flea Treatment Tablets, Contributors to 1800PetMeds.com, As of December 2013
We found more than 570 user reviews here for Capstar for Dogs and Cats. Pet owners generally find this product safe and effective, giving it an overall rating of 4.2 stars. The most common complaint is that it kills adult fleas only and can't treat an infestation on its own.
Review: Capstar Flea Treatment Dog (Blue), 2-25 lbs, 6 tablets, Contributors to Amazon.com, As of December 2013
3. All Feline Hospital
Vets at All Feline Hospital in Lincoln, Neb., say Capstar for Dogs and Cats kills adult fleas within 30 minutes, making it great for fast relief in cats with flea allergies. However, it must be combined with topical treatments to completely eliminate fleas from the home.
Review: Flea Eradication, Staff of All Feline Hospital, Not Dated
There are about 100 reviews for Capstar for Cats and Dogs at Petco.com, most of them positive. The product earns 4.6 stars out of 5 overall, and 94 percent of users recommend it. Most users say Capstar is safe, effective and fast-working.
Review: Capstar Flea Tablets for Pets, Contributors to Petco.com, As of December 2013
PetSmart.com has only about 35 reviews for Capstar for Cats and Dogs, but they are nearly all positive. Owners give the pills 4.6 stars out of 5 overall, saying they're fast and effective where other flea treatments have failed. A few owners report negative side effects, but no dangerous ones.
Review: Capstar Adult Flea Killer Tablets, Contributors to PetSmart.com, As of December 2013
In this article, veterinarian Carol S. Foil says Capstar for Dogs and Cats is safe and "offers extremely rapid and complete killing of adult fleas." However, she notes that it must be combined with another product for long-term flea control.
Review: Flea Control, Carol S. Foil, Not Dated
This directory from the Natural Resources Defense Council rates Capstar for Dogs and Cats one of the safest flea treatments available. Editors say it poses little danger to either pets or humans, but they still recommend consulting a vet before use.
Review: GreenPaws Flea and Tick Products Directory, Editors of SimpleSteps.org, Not Dated