Capguard Flea Tablets from Sentry help keep your dog flea-free and comfortable. This product contains nitenpyram, an ingredient designed to control mature fleas. This medication is oral, easy to feed directly to your dog, and the tablet begins working within 30 minutes. Capguard Flea Tablets are not only effective for killing fleas, but hassle-free! Available for dogs under 25 lbs and over 25 lbs.