CAPSTAR (nitenpyram) is a fast-acting dog flea treatment tablet for use with dogs that starts killing fleas in only 30 minutes. A single dose of CAPSTAR Oral Flea Treatment kills 90% of adult fleas within 4 hours for dogs. Give this oral flea treatment and watch the dead fleas fall off your pet. CAPSTAR flea tablets are available for dogs and puppies 25.1-125 pounds, and 4 weeks of age or older.