Ivermectin Usage in Cats: A Comprehensive Guide to Dosage and Potential Side Effects.

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Ivermectin, a prescription medication, finds its application in treating parasitic infestations not only in cats but also in various other animals. Among its chief usages for felines, preventing heartworm infection takes the forefront, often through the administration of a monthly tablet known as Heartgard. Additionally, your veterinarian might prescribe ivermectin to address an array of parasitic issues such as ear mites and scabies.

This versatile medication is available in tablet, liquid (used for ear application), and injectable formulations. Employing ivermectin at recommended dosages is generally safe for cats; however, its usage at elevated doses can lead to severe side effects.

Ivermectin for Cats Overview

Medication Type:	Anti-parasitic
Medication Form:	Tablets and topical liquid (ear drops); injectable forms licensed for use in farm animals.
Brand Names:	Heartgard and Acarexx otic suspension licensed for use in cats. Various products licensed for use in farm animals.
Effects:	Licensed for preventing heartworm and treating ear mites in cats in the United States. Also effective against other internal and external parasites off-label, including scabies.
Available Dosages:	Heartgard tablets 55 micrograms (up to 5 pounds) and 165 micrograms (5 to 15 pounds). Acarexx otic suspension 0.01% solution. Injectable 10 milligrams/milliliter various products licensed for use in farm animals.
Potential Side Effects:	Few when used at appropriate doses. Vomiting (less than 0.2% of cats) and diarrhea (less than 0.3% of cats).
Precautions:	Do not use in kittens younger than 6 weeks of age.
Contraindications:	Avoid using alongside benzodiazepines, ketamine, erythromycin, spinosad, or certain anti-fungal treatments.

Exploring Ivermectin Usage in Felines

Ivermectin plays a crucial role in feline health, primarily as a preventive measure against heartworm infection. Dirofilaria immitis, commonly known as heartworms, can lead to a grave illness. This ailment emerges following the bite of an infected mosquito and can result in symptoms like coughing, respiratory issues, and vague signs such as weight loss or vomiting. In severe instances, it might even culminate in sudden death.

Due to the challenging nature of heartworm treatment, prevention remains paramount. Administering an ivermectin tablet (Heartgard) to your cat on a monthly basis at home is a recommended preventive measure.

Beyond heartworm prevention, ivermectin proves effective in treating other internal and external parasites afflicting cats, such as ear mites and scabies. However, it’s worth noting that this medication does not combat fleas or tapeworms.

Ivermectin Dosage Guidelines for Cats

The FDA sanctions the use of ivermectin in cats for heartworm prevention via Heartgard tablets. The recommended dosage is a minimum of 12 micrograms per pound, administered once a month. However, prior to commencing preventative treatment, consulting your veterinarian to evaluate your cat’s susceptibility to active heartworm infection is crucial.

Furthermore, the FDA has granted approval for an ivermectin solution, labeled Acarexx otic suspension, specifically for treating ear mite infestations in cats.

Cat Weight	Tablets per month	Strength
Up to 5 pounds	1	55 micrograms
5 to 15 pounds	1	165 micrograms

Heartgard Oral Tablets: Safeguarding Feline Hearts

Heartgard tablets serve as the sanctioned solution for preventing heartworm infection in cats aged 6 weeks and above. Available in two tablet sizes—55 micrograms (designed for cats up to 5 pounds) and 165 micrograms (tailored for cats weighing 5 to 15 pounds)—these tablets provide a robust defense. Administer one tablet to your cat every month, consistently throughout the year.

The initial dose should be administered within 30 days of your cat’s earliest possible exposure to mosquitoes. Subsequently, the final dose should be given no later than 30 days after the last potential exposure. To optimize effectiveness, strive to administer Heartgard on the same day each month.

In addition to shielding against heartworm, monthly usage of Heartgard extends protection against hookworm infection in your feline companion.

Acarexx Otic Suspension: Nurturing Ear Health

For adult ear mite infestations in cats and kittens over 4 weeks of age, Acarexx otic suspension comes to the rescue. Containing 0.01% ivermectin, this solution is administered by your veterinarian, with 0.5 milliliters of liquid placed into your cat’s ear canal. Typically, a single dose suffices; however, a repeat treatment might be necessary if deemed by your vet.

Off-Label Utilization of Ivermectin: Exploring Beyond Boundaries

In certain cases, veterinarians might employ ivermectin in “off-label” capacities, deviating from the FDA’s original approval. This includes varied doses and formulations to treat different parasites in cats, such as scabies. For instance, your veterinarian might opt to use an ivermectin injection, authorized for use in farm animals, to address ear mites or scabies in your cat. Always trust your veterinarian’s judgment for these alternative applications.

Administering Ivermectin to Cats: A Step-by-Step Guide

If you’re tasked with administering ivermectin to your cat at home, the likely scenario involves Heartgard tablets. Given their chewable nature, there are a couple of methods you can employ:

Hand Offering or Mixing with Food: Present the Heartgard tablet in your open hand or mix it with a small portion of your cat’s food. The palatability of the tablet often encourages consumption.
Direct Administration: In cases where your cat refuses to consume the tablet willingly, you can break it into smaller fragments and place them directly into their mouth. Ensure your cat has consumed the entire tablet; if any doubts arise, it’s best to offer a new tablet.

Potential Side Effects of Ivermectin for Cats

When employed at recommended dosages, ivermectin proves highly safe for cats. The possibility of side effects, such as vomiting or diarrhea, is minimal. Clinical trials indicate that these effects were observed in less than 0.3% and less than 0.2% of cats, respectively.

Should you suspect any adverse reaction in your cat due to ivermectin, promptly consult your veterinarian for guidance. Additionally, it’s advisable to report the suspected reaction to the manufacturer, Boehringer Ingelheim Animal Health USA. This collaborative effort contributes to ensuring feline well-being and overall medication safety.

Ivermectin Overdose and Emergencies: Understanding the Risks and Responses

Ivermectin boasts a broad safety threshold in cats, resulting in rare occurrences of overdose with heartworm prevention tablets. Nevertheless, if your cat happens to consume a quantity surpassing the recommended dose, promptly consulting your veterinarian is imperative for appropriate guidance.

However, it’s important to note that ivermectin is occasionally utilized off-label in cats, often involving formulations designed for substantially larger animals like cattle, sheep, and horses. Regrettably, overdosing is not uncommon when these formulations are used inappropriately due to their high concentrations. Cats can unintentionally ingest excessive amounts by consuming such large animal products, such as licking remnants of horse wormer from a syringe.

If your cat ingests an overdose of ivermectin, symptoms may manifest within two to three hours. However, in less severe instances, symptoms could develop more gradually. Signs of ivermectin toxicosis encompass:

Depression
Weakness
Dilated pupils
Loss of vision
Impaired coordination (ataxia)
Collapsing
Tremors
Seizures
Coma

Cats grappling with ivermectin toxicosis require immediate, intensive veterinary intervention. This underscores the importance of swift action in addressing potential emergencies, safeguarding your feline companion’s well-being.

Potential Interactions with Ivermectin: Ensuring Feline Safety

Ivermectin is notably compatible with cats undergoing routine vaccinations, antibiotic treatments, steroid regimens, and various other antiparasitic medications. Yet, vigilance is crucial—before administering ivermectin, inform your veterinarian about all ongoing treatments, which includes herbal or nutritional supplements, to ensure a comprehensive understanding of your cat’s medical profile.

Specifically, exercise caution when considering ivermectin if your cat is concurrently receiving benzodiazepines, ketamine, erythromycin, spinosad, or specific anti-fungal treatments.

Proper Storage of Ivermectin

To maintain the potency and effectiveness of ivermectin products, store them at room temperature, away from direct exposure to sunlight. After use, always return any remaining tablets, still encased in their foil blister, to their original packaging. This safeguards the tablets from light, preserving their quality for future use.

Frequently Asked Questions about Ivermectin and Cats

Is Ivermectin safe for cats?

Ivermectin is considered highly safe for cats when administered at appropriate doses. The FDA has sanctioned the usage of ivermectin to prevent heartworm infection in cats, with a recommended minimum dose of 12 micrograms per pound once a month. This medication exhibits a wide safety margin in felines, with single-dose tolerance studies indicating a 30-fold safety margin beyond the minimum recommended dosage.

Why is Ivermectin given to cats?

Primarily, ivermectin is employed in cats to prevent heartworm infection. Additionally, it proves effective against a range of internal and external parasites like ear mites and cat scabies. This utilization often falls under the category of “off-label” use, implying that it’s applied to treat conditions beyond the scope of the FDA’s initial approval.

Is Ivermectin effective for deworming cats?

Although ivermectin can be used to prevent certain types of worms, such as roundworms, its predominant use in cats is for heartworm prevention. Commonly, other wormers are preferred for deworming purposes. However, it’s important to note that ivermectin does not combat tapeworms effectively.

What’s the appropriate Ivermectin dosage for cats?

The FDA’s approved dose for preventing heartworm in cats using ivermectin is a minimum of 12 micrograms per pound, administered once a month. It’s worth highlighting that ivermectin can also be used off-label at various doses to treat diverse internal and external parasites. Instances of ivermectin toxicosis have been reported at doses exceeding 100 micrograms per pound.

What happens if a cat is given an excessive amount of Ivermectin?

Signs of ivermectin overdose in cats might become evident within two to three hours post-ingestion. Symptoms encompass depression, weakness, dilated pupils, loss of vision, impaired coordination, tremors, and collapsing. If an overdose is suspected, swift action is crucial—seek immediate veterinary assistance to ensure the well-being of the cat.

View Sources

Heartgard prescribing information: https://docs.boehringer-ingelheim.com/PI/Paras/Heartgard_for_Cats_PI_with_BI_logo_-2020.pdf