Heartgard Plus Brown for Large Dogs 23–45kg is a monthly beef-flavoured heartworm chew dosed for the large-breed weight tier. It prevents heartworm disease and treats roundworm and hookworm in a single palatable monthly dose.

Each chew combines ivermectin and pyrantel at the dose calibrated for dogs in the 23–45kg range. Ivermectin kills immature heartworm larvae before they can establish infection, while pyrantel treats and controls roundworm and four species of hookworm. The real-beef soft chew is designed to be taken voluntarily as a treat.

Large-breed dogs need higher ivermectin doses to maintain heartworm protection, and the brown pack is specifically calibrated for the 23–45kg tier. The chew format keeps monthly dosing simple, which is the main factor in whether heartworm prevention actually happens consistently.