Heartgard Plus Chewables for Dogs 26-50 lbs (12-22 kg)

Description

Heartgard Plus Chewables for Dogs 26-50 lbs (12-22 kg) deliver ivermectin at 136 mcg and pyrantel at 114 mg per monthly dose, calibrated to the green-coded weight band for medium-sized dogs. Manufactured by Boehringer Ingelheim and approved under FDA NADA #140-971, each chewable targets heartworm larvae at the tissue stage alongside five species of adult intestinal roundworms and hookworms. Dogs in this weight range receive one green-coded chewable every 30 days, year-round in heartworm-endemic regions or throughout the active mosquito season.

Recommended for

Dogs weighing 26 to 50 lbs (12 to 22 kg), from 6 weeks of age.

Indication/Coverage

For dogs suffering from, or at risk from, mixed parasitic infections, Heartgard Plus Chewables (26-50 lbs) carry the following labeled indications:

• Heartworm prevention (Dirofilaria immitis, L3/L4 larvae): Ivermectin at 6 mcg/kg eliminates tissue-stage larvae within 30 days of mosquito-transmitted infection, preventing larval maturation into adult heartworms.
• Roundworm treatment and control (Toxocara canis, Toxascaris leonina, adults): Pyrantel pamoate induces neuromuscular paralysis in both roundworm species through acetylcholine-mediated depolarising blockade, causing expulsion from the gastrointestinal tract.
• Hookworm treatment and control (Ancylostoma caninum, Uncinaria stenocephala, Ancylostoma braziliense, adults): Pyrantel pamoate eliminates all three hookworm species through the same depolarising neuromuscular blockade, covering the primary hookworm ( caninum), the northern hookworm (U. stenocephala), and the subtropical species (A. braziliense).

Key Benefits

Heartgard Plus Chewables (26-50 lbs) carry the following clinically relevant attributes specific to this weight variant:

• Labeled from 6 weeks. Administration is supported in dogs from 6 weeks of age, including growing medium-breed puppies entering the 26 lb threshold before 8 to 10 weeks.
• Dual-mechanism coverage. Ivermectin and pyrantel pamoate operate through distinct pharmacological pathways: ivermectin potentiates glutamate-gated chloride channels to eliminate heartworm larvae, while pyrantel acts as a depolarising neuromuscular blocking agent against adult intestinal nematodes.
• Retroactive larval clearance. Each monthly dose eliminates immitis larvae acquired up to 30 days prior, providing a backward-acting window that accommodates minor delays in administration.
• Six-parasite reach per dose. One chewable addresses heartworm, two roundworm species, and three hookworm species simultaneously, removing the need for separate intestinal worming products in dogs on this regimen.
• Palatable oral format. The beef-flavored chewable was consumed at first offering by the majority of dogs in acceptability trials, reducing the handling difficulty and dose-loss risk associated with spot-on application in dogs resistant to topical treatments.
• Breeding-population safety established. Clinical trials conducted by Boehringer Ingelheim confirmed no adverse effects in pregnant bitches, stud dogs used for breeding, or puppies aged 6 weeks and older at the labeled dose of 6 mcg/kg ivermectin.
• Broad concurrent-medication compatibility. Heartgard Plus has been co-administered with flea collars, dips, shampoos, anthelmintics, antibiotics, vaccines, and steroid preparations in clinical trial settings without recorded adverse interaction events at label doses.
• Wide safety margin at recommended dose. Heartgard Plus showed no toxicity signs at 10 times the recommended dose (60 mcg/kg) in ivermectin-sensitive Collie-breed dogs, establishing a substantial buffer above the therapeutic level for this weight band.

Caution

Hazards to Humans

Keep Heartgard Plus Chewables out of reach of children at all times. Accidental ingestion by a person requires immediate contact with a physician; treating physicians may contact a Poison Control Center for case-specific guidance. Store in a secure location inaccessible to children and away from food preparation areas.

Hazards to Domestic Animals

Heartgard Plus Chewables (26-50 lbs) are for oral administration in dogs aged 6 weeks and older, weighing between 26 and 50 lbs (12 to 22 kg). Dogs with an existing heartworm infection must receive adulticide treatment to eliminate adult D. immitis and microfilariae before commencing this preventive, as ivermectin at the label dose does not clear adult worms. Consult a veterinarian before administering to debilitated, aged, pregnant, or nursing dogs. Dogs with a confirmed or suspected MDR1 (ABCB1) gene mutation should not receive this product without prior veterinary assessment, as ivermectin sensitivity at elevated doses has been documented in Collie-related breeds.

Possible Side Effects

Monitor your dog in the period following each monthly administration of Heartgard Plus Chewables, with particular attention after the initial dose.

Post-approval adverse drug experience data submitted to FDA/CVM documents the following reactions in decreasing order of reporting frequency:

• Vomiting: The most frequently reported adverse event; in controlled clinical field trials, vomiting within 24 hours occurred in 1.1% of administered doses, though post-approval reporting captures higher frequency in real-world use.
• Diarrhea: Ranked alongside vomiting in post-approval reports; a transient hypersensitivity-type diarrhea has also been observed in dogs carrying circulating microfilariae treated with ivermectin, attributed to dying microfilariae rather than direct drug toxicity.
• Lethargy and anorexia: Reduced activity and appetite loss have been recorded; these signs are typically self-limiting, but persistence beyond 48 hours warrants veterinary assessment.
• Neurological signs: Seizures, ataxia, and muscle tremors appear at lower reporting frequency in post-approval data. Dogs with a history of seizures or neurological conditions should not receive this product without prior veterinary clearance.
• Hypersalivation and pruritus: Excessive salivation and itching have been noted at lower frequency; these reactions are generally transient.
• Choking and intestinal obstruction: Cases have been reported when the chewable is ingested whole without chewing. For dogs that bolt treats, break the tablet into pieces before offering.

If any of the above signs occur, contact a veterinarian before the next scheduled dose.