PETARMOR CAPACTION (nitenpyram) oral flea tablets contain the same active ingredient as CAPSTAR. PETARMOR CAPACTION oral flea tablets begin working in just 30 minutes. PETARMOR CAPACTION achieves greater than 90% effectiveness against adult fleas on cats within 6 hours. PETARMOR CAPACTION is your convenient over-the-counter oral flea treatment. No prescription needed. This oral flea tablet is intended for cats 4 weeks old old and weighing between 2 to 25 pounds. CAPACTION Flea tablets are even safe for use on pregnant or breeding cats.