Heartgard for Dogs

Heartgard Plus (ivermectin/pyrantel) is a prescription-only monthly chew for dogs. It prevents heartworm disease and also treats and controls common intestinal worms—roundworms and hookworms. Generic name: ivermectin with pyrantel. Brand name: Heartgard Plus. Plain-language class: heartworm prevention and dewormer (chewable). Species: dogs. Your veterinarian can discuss heartworm testing, whether this product is right for your dog, and what to do if a dose is missed.

Top owner questions and quick answers: - What does Heartgard Plus do? It prevents heartworm disease and also treats and controls common intestinal roundworms and hookworms. It does not cover fleas, ticks, whipworms, or tapeworms. Your veterinarian can recommend additional preventives if needed. - How often is it given, and what if we missed a dose? It’s designed for monthly use. If a dose is late or missed, call us so the veterinarian can advise next steps; giving doses late can reduce protection, and testing may be recommended after a lapse. Don’t give two doses at once unless the veterinarian directs you. - Does my dog need a heartworm test? Dogs 7 months and older are typically tested before starting prevention, and annual testing is recommended even when on prevention. After a significant lapse in dosing, your veterinarian may recommend retesting about 6 months later. - Is it safe for Collies or puppies? At the labeled prevention dose, Heartgard Plus has a wide safety margin, including in Collie-type breeds, and is labeled safe for puppies 6 weeks of age and older. Your veterinarian will confirm if it’s appropriate for your individual dog (including breeding or pregnant dogs). - What side effects should I watch for? Side effects are uncommon; vomiting or diarrhea may occur. Other reported reactions include lethargy, loss of appetite, dilated pupils, incoordination, or drooling. If you ever see facial swelling, hives, trouble breathing, or collapse after any medication, seek emergency care immediately and contact us. If your dog spits out or vomits the chew, please call before giving more so our veterinarian can advise whether to re-dose.

Common owner reports within 24 hours of a Heartgard Plus chew include brief vomiting or soft stool/diarrhea, mild tiredness, less interest in food, and occasional drooling. These are usually short‑lived and self‑limited. In field use, vomiting or diarrhea within 24 hours was reported in about 1% of doses; other reactions reported after approval include lethargy, decreased appetite, itching, wobbliness, tremors, and seizures. Call the clinic the same day if vomiting happens more than once, diarrhea lasts beyond 24 hours, there is blood in stool or vomit, your dog won’t eat or drink, or seems unusually quiet or “out of it.” If your dog tends to swallow treats whole, note that the chew can be a choking/obstruction risk; call promptly if there is gagging, repeated retching, persistent vomiting, or abdominal discomfort. If vomiting occurs soon after dosing or your dog may have eaten more than one chew or the wrong size, call us so the veterinarian can advise next steps and whether any monitoring is needed. Go to an emergency clinic now for severe signs: collapse; trouble breathing; facial swelling or hives; severe weakness; staggering/wobbliness, dilated pupils, tremors, or seizures. These can indicate a serious reaction or an overdose. Your veterinarian can discuss whether and how to continue prevention and how to reduce risk for future doses.

Form: Heartgard Plus is a beef‑flavored chewable for dogs. Offer it like a treat and encourage chewing; do not remove it from the blister until ready to give. For dogs that tend to gulp treats, you can break the chew into pieces. You may also place the chew intact in a small amount of food to encourage chewing—watch to be sure the entire dose is eaten at one time and not split between bites or meals. Keep unused chews in the original blister/card to protect from light. If any of the chew is dropped, spit out, or not fully eaten, contact the veterinarian for guidance before giving more. The product label notes that redosing is recommended when part of the dose is lost, but this decision should be made by the veterinarian for each case. If your dog vomits shortly after taking the chew, call the clinic before repeating a dose. Urgent safety: Rare reports include choking or intestinal obstruction if swallowed without chewing, and neurologic or gastrointestinal side effects. If the dog has choking/gagging that doesn’t stop, repeated vomiting, a painful or bloated abdomen, trouble breathing, collapse, or seizures after a dose, treat this as an emergency and seek immediate veterinary care. If a dog refuses the chew despite tricks, your veterinarian can discuss other FDA‑approved preventive options in different forms (e.g., non‑chewable formats) or, if medically appropriate, whether a reputable compounding pharmacy is an option; note that compounded animal drugs are not FDA‑approved and must be directed by the veterinarian.

Heartgard Plus is a prescription-only preventive. A veterinarian must approve all refills and there must be a valid veterinarian–client–patient relationship (VCPR). Dogs should have a current negative heartworm test to continue prevention; annual testing is recommended by expert guidelines. If the last heartworm test is over 12 months ago or unknown, schedule testing before routing the refill for approval. Typical turnaround for refill approvals is about 1 business day; if the pet is out of doses, flag the request for same‑day review. Final authorization and quantity are at the veterinarian’s discretion. When taking a refill call, gather: pet and owner names, medication name (“Heartgard Plus”) and chew size/color if known, preferred quantity (commonly 6 or 12 doses), last dose date and whether any doses were missed, any side effects, the dog’s current weight, and pickup vs. online pharmacy preference. For online pharmacies, record the pharmacy name and contact (phone/fax/email) or whether the client wants a written prescription. Note that any product substitutions must be approved by the veterinarian. Your veterinarian can discuss testing schedules, refill quantities, and alternatives if needed. Escalate immediately to a technician or veterinarian if the dog missed two or more months of prevention, or if the caller reports cough, trouble breathing, exercise intolerance, fainting/collapse, or other concerning signs. Do not promise a refill in these cases; route for clinical review right away.

Escalate to a veterinarian or technician immediately if, after a dose or accidental ingestion of multiple chews, the dog shows any neurologic signs: wobbliness or trouble walking, dilated pupils, sudden vision changes, shaking/tremors, seizures, extreme lethargy, trouble breathing, or collapse. These can indicate ivermectin toxicity and are an emergency. Keep the caller on the line while you page medical staff; if the dog is actively seizing, not breathing well, or collapsing, direct them to the nearest emergency hospital now. Watch for severe allergic reactions within minutes to hours: facial swelling, hives, repeated vomiting/diarrhea, pale gums, difficulty breathing, or collapse—treat as an emergency and transfer to medical staff right away. If the chew was swallowed whole and the dog is gagging, retching, repeatedly vomiting, or showing abdominal pain or bloating, escalate immediately due to reported risks of choking or intestinal obstruction with this product. Stop front-desk counseling and get a vet/tech if the dog has not had a current negative heartworm test or has missed multiple monthly doses; macrocyclic lactones can trigger hypersensitivity reactions in dogs with circulating microfilariae. Your veterinarian can discuss testing status, refill safety, and next steps.

Heartgard Plus contains ivermectin and pyrantel. Flag and document any other meds or supplements the dog is taking, because some drugs can raise ivermectin levels or counteract pyrantel. Highest‑priority flags: spinosad flea products (Comfortis or in Trifexis), azole antifungals (especially ketoconazole), and cyclosporine—these can inhibit drug transport (P‑glycoprotein) and increase the chance of neurologic side effects. Also flag any use of other macrocyclic lactones or separate OTC dewormers; pyrantel should not be given with piperazine because they work against each other. Your veterinarian can discuss if the combination is appropriate for this pet and adjust the plan if needed. Commonly co‑prescribed medications to ask about and flag when applicable: - Flea/tick preventives: spinosad products (Comfortis/Trifexis) require review due to a known interaction with high ivermectin doses; label‑use heartworm preventives with spinosad are generally considered compatible, but still document brand and timing. Isoxazolines (e.g., NexGard/Simparica/Bravecto) are typically used with preventives—still record brand/timing for the chart. - Antifungals: ketoconazole/itraconazole—possible to raise ivermectin exposure; flag for DVM review. - Immunomodulators: oral cyclosporine (Atopica)—P‑gp interaction potential; flag. - OTC human meds owners may give: loperamide (Imodium)—avoid without DVM guidance, especially in herding breeds; OTC dewormers with piperazine—do not combine with pyrantel; bring packaging for review. If an owner mentions any of these, pause scheduling/dispensing and hand off to a veterinarian for direction. Urgent red flags after dosing any combination: tremors/twitching, stumbling/ataxia, seizures, excessive drooling, dilated pupils, sudden blindness, or marked disorientation. Escalate immediately to the veterinarian or direct the client to the nearest emergency hospital if these occur. Your veterinarian can advise on breed‑specific risks (e.g., MDR1 breeds) and safe product combinations.

Storage: Keep Heartgard Plus in its original blister card and carton at controlled room temperature 68–77°F (20–25°C); brief excursions 59–86°F (15–30°C) are allowed. Protect from light. Remove only one chew at a time and return the blister to the box. Keep out of reach of children and in a secure place away from pets—these chews are flavored and dogs may eat the whole box if accessible. If there are concerns about temperature exposure or damaged packaging, your veterinarian can advise whether to dispense or replace the product. Handling at pickup: Verify the expiration date and intact blister seals. Do not repackage. Do not split, crush, or save partially chewed/broken pieces unless the veterinarian specifically instructs; keep chews sealed until ready to give. If a chew was removed from the blister but not given, ask the veterinarian how to proceed. Disposal: For expired or unneeded chews, use a drug take‑back program when available. If no take‑back is available and the medicine is not on FDA’s flush list, mix the chews with an unappealing substance (e.g., used coffee grounds or cat litter), seal in a bag or container, and place in household trash. Do not flush unless a medicine is specifically listed on the FDA flush list. If a child ingests any amount or a pet eats more than intended (e.g., multiple chews or a whole carton), contact a physician/Poison Control or the veterinarian/animal poison control immediately.

Scheduling: Set an annual heartworm screen every 12 months for all dogs on Heartgard Plus. The American Heartworm Society now recommends doing both an antigen test and a microfilaria test at these visits to be sure prevention is working. If a dog is starting prevention at 7 months of age or older, or is restarting after a lapse/missed doses, place follow‑up reminders for a heartworm test about 6 months after restarting, again at 12 months, then annually; the veterinarian should confirm the exact timeline. Fecal monitoring: Because dogs can be re‑exposed to roundworms and hookworms that Heartgard Plus targets, schedule fecal parasite checks in healthy adult dogs at least twice per year (puppies more often per clinician direction). These can be paired with wellness exams or set as quick technician visits. Your veterinarian can tailor frequency based on local risk and the pet’s lifestyle. What to watch for after dosing: Mild vomiting or diarrhea can occur within 24 hours. Rarely, neurologic signs like tremors, stumbling, or seizures have been reported. If an owner reports severe or worsening vomiting/diarrhea, weakness, trouble walking, or any seizure/collapse after a dose, advise immediate veterinary evaluation and help direct them to the nearest emergency hospital. The veterinarian can discuss any additional lab work or monitoring needs.

Heartgard Plus is a monthly, prescription chew for dogs that helps prevent heartworm disease and also treats and controls common intestinal worms (roundworms and hookworms). It is for dogs only and is labeled safe for puppies 6 weeks of age or older. All dogs should have a current negative heartworm test before a veterinarian prescribes prevention. Commonly reported side effects are digestive upset (vomiting or diarrhea); neurologic effects have been reported rarely. The FDA notes a risk of choking or intestinal obstruction if a chew is swallowed whole; pets should be monitored when given the chew. For questions about breed sensitivities, missed/late doses, vomiting after a dose, or product selection, your veterinarian can discuss what is appropriate for the individual dog. Escalate immediately if a dog has trouble walking, seizures, collapse, severe or persistent vomiting/diarrhea, facial swelling/hives, trouble breathing, or if the dog ate multiple chews or the wrong product—this requires emergency evaluation.