Heartworm disease is an invisible yet potentially fatal threat to dogs, transmitted by a single mosquito bite. This serious condition can lead to irreversible damage to a dog’s lungs and heart. HEARTGARD® Plus (ivermectin/pyrantel) chewables offer a vital monthly solution, not only preventing heartworm disease but also treating and controlling common intestinal parasites like hookworms and roundworms. Given the prevalence of heartworm cases across all 50 states, year-round protection is crucial for maintaining your dog’s health and well-being.
Understanding HEARTGARD® Plus Chewables
HEARTGARD® Plus chewables are designed for ease of administration, featuring a palatable, real-beef formulation that dogs readily accept. They are safe for puppies as young as 6 weeks of age. The American Heartworm Society strongly recommends continuous, year-round heartworm prevention for all dogs. It is essential to consult with your veterinarian to establish a preventative program and ensure your dog has a current annual heartworm test on record before starting HEARTGARD® Plus.
How HEARTGARD® Plus Works
The efficacy of HEARTGARD® Plus stems from its two active ingredients: ivermectin and pyrantel. Ivermectin is the key component in preventing the development of heartworm larvae within the dog’s system. Concurrently, pyrantel actively treats and controls infections of hookworms and roundworms, two of the most frequently encountered intestinal nematode parasites in dogs.
Benefits of HEARTGARD® Plus:
- Prevents Heartworm Disease: Effectively safeguards your dog from this dangerous parasitic infection.
- Treats Intestinal Parasites: Also addresses and controls common hookworm and roundworm infestations.
- Trusted Brand: Part of the HEARTGARD® brand, trusted by pet owners for over 2 billion doses.
- Palatable Formulation: A delicious monthly real-beef chew that dogs enjoy.
- Wide Age Range: Suitable for puppies from 6 weeks of age and older.
Administration and Safety Information
Administer one HEARTGARD® Plus chewable once a month, ideally on the same day each month, to maintain optimal protection. To prevent choking or intestinal obstruction, encourage your dog to chew the product rather than swallow it whole. For dogs that tend to swallow treats quickly, the chewable can be broken into smaller pieces. In cases where a dose is missed, administer it as soon as possible and resume the monthly regimen. If you suspect an overdose, seek immediate veterinary attention. Keep the product securely stored away from children and other pets to prevent accidental ingestion.
Potential Side Effects
While HEARTGARD® Plus is generally well-tolerated, rare instances of vomiting or diarrhea within 24 hours of administration have been reported. Other less common adverse reactions include depression, lethargy, anorexia, mydriasis, ataxia, staggering, convulsions, and hypersalivation. Always discuss any pre-existing conditions or concerns with your veterinarian before starting any new medication.
Important Considerations Before Use:
- Heartworm Testing: All dogs must be tested for existing heartworm infections before commencing a preventive program. HEARTGARD® Plus is not effective against adult heartworms; infected dogs require specific treatment to eliminate adult worms and microfilariae before starting a preventive regimen.
- Drug Interactions: When switching from another heartworm preventive, administer the first dose of HEARTGARD® Plus within 30 days of the last dose of the previous medication.
- Allergies: Do not administer HEARTGARD® Plus to dogs with a known allergic reaction to ivermectin or pyrantel.
- Species Specificity: HEARTGARD® Plus is formulated exclusively for dogs and should never be given to cats or other animals.
Understanding Intestinal Parasites and Heartworm Disease
How Dogs Contract Hookworms and Roundworms:
Hookworm larvae can be transmitted through the skin, via a mother’s milk, or by ingesting larvae from contaminated soil or grass. Roundworm larvae can be passed from mother to puppies through the placenta or milk, or by ingesting infective eggs from contaminated soil.
What is Heartworm Disease?
Heartworm disease is caused by Dirofilaria immitis, parasitic worms transmitted to dogs through infected mosquitoes. The larvae develop under the skin and then migrate to the heart and lungs, where they mature into adult worms measuring 5 to 12 inches.
Signs of Heartworm Disease:
While not all dogs show symptoms, advanced heartworm disease can manifest as:
- A persistent dry cough
- Lethargy and reluctance to exercise
- Decreased appetite and weight loss
- Abdominal swelling due to fluid accumulation
- Difficulty breathing and rapid respiration
Reducing the Risk of Heartworm Disease:
- Minimize Mosquito Exposure: Eliminate standing water, avoid mosquito-prone areas, and limit outdoor time during peak mosquito activity.
- Consistent Monthly Prevention: Utilize year-round, broad-spectrum preventatives like HEARTGARD® Plus to target heartworm larvae before they mature.
- Annual Testing: Ensure your dog receives an annual heartworm test before obtaining a prescription for preventatives.
Can Heartworm Disease Be Treated?
While treatment is possible, heartworm disease is a serious and costly condition that can lead to heart failure, permanent lung damage, and death. Prevention remains the most effective and humane approach.
Storage and Additional Information
Store HEARTGARD® Plus chewables between 68°F and 77°F (20°C – 25°C), with permitted excursions between 59°F and 86°F (15°C – 30°C). Protect the product from light. HEARTGARD® Plus is available in sizes for dogs up to 100 pounds, with combinations available for larger dogs. For specific product questions, contact Boehringer Ingelheim Animal Health at 1-888-637-4251.
References
- Lynn RC, Duquette RA. Chapter 6. Antiparasitic Drugs. In: Bowman DD, ed. Georgis’ Parasitology for Veterinarians. 11th ed. St. Louis, MO: Elsevier; 2021: 286-348.
- HEARTGARD® Plus (ivermectin/pyrantel) Chewables [Freedom of Information Summary; NADA140-971]. Duluth, GA: Boehringer Ingelheim Animal Health USA Inc.
- Current Canine Guidelines for the Prevention, Diagnosis, and Management of Heartworm Infections in Dogs 2024. American Heartworm Society. https://www.heartwormsociety.org/images/pdf/2018-AHS-Canine-Guidelines.pdf. Accessed May 10, 2022.
- Data on file at Boehringer Ingelheim
- Data on file at Boehringer Ingelheim
- Carithers D, Miro G. Pet Owner Educational Atlas: Parasites. Zaragosa, Spain: Grupo Asis; 2012.
- Heartworm Basics. American Heartworm Society. https://www.heartwormsociety.org/pet-owner-resources/heartworm-basics. Accessed February 11, 2025.
- Weigh the Costs Infographic. American Heartworm Society. https://d3ft8sckhnqim2.cloudfront.net/images/infographics/0010-weigh-the-costs.jpg. Accessed February 11, 2025 .
