: Your vet must test your dog for existing heartworms before writing the prescription, as giving the preventative to an infected dog can be dangerous.
: Ensure you select the correct box color based on your dog's current weight (e.g., Yellow for 26–50 lbs, Blue/White for 51–100 lbs).
: Before buying, search for the medication on GoodRx for Pets to compare prices across different pharmacies.
: Typically listed as one of the most affordable options for prescription pet meds. Comparison of Sentinel Products Sentinel Flavor Tabs Sentinel Spectrum Form Beef-flavored tablet Beef/Bacon flavored chewable Prevents Heartworms & Fleas Heartworms & Fleas Treats Hookworms, Roundworms, Whipworms Hookworms, Roundworms, Whipworms + Tapeworms Active Ingredients Milbemycin Oxime, Lufenuron Milbemycin Oxime, Lufenuron, Praziquantel Starting Age 4 weeks and older 6 weeks and older 💡 Quick Buying Tips
: A licensed pharmacy frequently offering competitive prices and "AutoShip" discounts.