Heartgard Plus

Why it is listed

Heartgard Plus is the classic monthly ivermectin/pyrantel chew: FDA-approved for heartworm, hookworms, and roundworms, including very young puppies with no weight floor. It is prescription-only and does not cover whipworm, tapeworm, fleas, or ticks. Test before starting; a veterinarian chooses whether this narrower chew is enough.

Pros & cons

Pros

• DailyMed / NADA 140-971: prevents canine heartworm disease; treats/controls roundworms (T. canis, T. leonina) and three hookworm species (A. caninum, U. stenocephala, A. braziliense).
• Labeled for dogs 6 weeks of age and older with no minimum weight — the lowest age floor on this list. Offer by hand or in food; chews may be broken for dogs that swallow treats whole (choking/obstruction has been reported).
• Label safety: Heartgard products showed no signs of toxicity at 10× the recommended ivermectin dose in ivermectin-sensitive Collies when used as recommended. Also labeled for pregnant/breeding bitches, studs, and puppies ≥6 weeks.

Cons

• Prescription only. Does not treat whipworms, tapeworms, fleas, or ticks — narrower intestinal coverage than Interceptor Plus or Advantage Multi.
• Post-approval (2022) reported events include vomiting, diarrhea, lethargy, anorexia, seizures, ataxia, muscle tremors, hypersalivation, and pruritus. Not effective against adult heartworms; test before starting.
• If the interval between doses exceeds 30 days, ivermectin efficacy can be reduced. Give on or about the same day each month.

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