Ivermectin for Dogs

Ivermectin is a broad-spectrum antiparasitic medication commonly used in veterinary medicine for dogs. Originally developed as an anti-parasitic drug for livestock, it has become a crucial treatment for a variety of parasitic infestations in pets, including mange, ear mites, and heartworm prevention. However, it's important for dog owners to understand the proper dosage, potential side effects, and its toxicity, particularly for certain dog breeds.

Following this article to explore more about ivermectin for dogs.

What is Ivermectin?

Ivermectin belongs to the macrocyclic lactone class of drugs. It works by paralyzing and killing parasites by increasing the permeability of their cell membranes to chloride ions. The drug has proven highly effective in controlling parasites such as heartworm larvae, mites, and certain gastrointestinal worms. It is widely available in oral, topical, and injectable forms.

Ivermectin Dosage for Dogs

The appropriate ivermectin dosage for dogs varies depending on the purpose of treatment. It is crucial to follow the veterinarian’s prescription closely to avoid overdosing, which can be dangerous.

General Dosage Guidelines

Heartworm prevention:
The typical dosage for preventing heartworms is 6 micrograms per kilogram of body weight. Commercial heartworm preventatives such as Heartgard usually contain ivermectin in this low dosage.
Also Read: Heartworm in Dogs

Treatment for intestinal parasites:
For intestinal parasites like hookworms or roundworms, a higher dose may be required, around 50 micrograms per kilogram of body weight.

Mange treatment:
Treating mange requires significantly higher doses of ivermectin. The usual dosage for treating mange is 300–600 micrograms per kilogram of body weight, administered orally. This dosage is given over several weeks, depending on the severity of the infestation.

Ear mite treatment:
Ivermectin is sometimes used as an off-label treatment for ear mites in dogs. The dosage for ear mites typically involves topical application in the ear canal. The specific amount will depend on the size of your dog and the formulation used.

It’s important to note that any off-label use of ivermectin should be done under a veterinarian’s supervision.

How to Use Ivermectin for Dogs

Ivermectin is available in different forms including oral tablets, topical creams, and injections. The form and dosage depend on the specific parasitic condition being treated.

1. Oral administration:
Ivermectin is often given orally in the form of a pill or liquid for preventing heartworm and treating internal parasites. Follow your veterinarian’s dosage instructions carefully.

2. Topical application:
Topical ivermectin is used for skin conditions like mange or ear mite infestations. This form is usually applied directly to the affected area or inside the ear canal.

3. Injection:
Ivermectin injections are less common in domestic dogs but may be used in severe cases of mange or other parasitic infestations.

Ivermectin for Dogs: Side Effects

Although ivermectin is generally safe when used at prescribed doses, some dogs may experience side effects. Common side effects include:

• Gastrointestinal distress:
  Nausea, vomiting, and diarrhea are among the most frequently observed side effects.
• Neurological issues:
  Symptoms such as lethargy, stumbling, uncoordinated movements, or drooling may indicate ivermectin toxicity.
• Skin irritation:
  When applied topically, ivermectin can sometimes cause localized irritation or redness.

Ivermectin Dosage for Dogs with Mange

Mange, caused by mites such as Sarcoptes scabiei or Demodex canis, requires a higher dosage of ivermectin compared to heartworm prevention. The typical dosage for mange is between 300 to 600 micrograms per kilogram, administered daily or weekly for several weeks. The duration of treatment depends on the severity of the infestation, and it should always be overseen by a veterinarian to monitor any potential side effects.
Related: Mange in Dogs

Ivermectin for Ear Mites in Dogs

Ivermectin is not always the first-line treatment for ear mites, but it can be effective. A topical formulation is typically used, applied directly into the ear. The dosage will vary depending on the formulation, and care should be taken to avoid applying too much, as overdosing can cause toxicity.
⇒Treatment for Ear Mites

Ivermectin Benefits for Dogs

Ivermectin is a highly effective treatment and preventative for various parasites. Some key benefits include:

• Heartworm prevention:
  One of the most significant uses of ivermectin is in the prevention of heartworms, which can be fatal to dogs if untreated.
• Treatment of mange:
  Ivermectin is effective in treating both sarcoptic and demodectic mange, two common parasitic skin diseases in dogs.
• Control of intestinal parasites:
  The drug is also useful in treating roundworms and hookworms.

Antidote for Ivermectin Toxicity in Dogs: Causes, Symptoms, and Solutions

Rate of Toxicity

Ivermectin toxicity occurs when dogs are exposed to excessive amounts of the drug. While it is rare when used at the appropriate dosage, toxicity is more common in certain breeds and when ivermectin is administered at high doses for off-label uses such as mange treatment.

Causes of Toxicity

Toxicity can occur from:

• Accidental overdose:
  If a dog accidentally ingests a large amount of ivermectin, toxicity can develop.
• Sensitivity in certain breeds:
  Some breeds, especially those with a genetic mutation in the MDR1 gene, are more susceptible to ivermectin toxicity.

Symptoms of Ivermectin Toxicity

Symptoms of ivermectin toxicity include:

• Lethargy
• Vomiting
• Dilated pupils
• Tremors or seizures
• Coma

Solution: Treating Ivermectin Toxicity

If you suspect your dog has ivermectin toxicity, contact a veterinarian immediately. There is no specific antidote for ivermectin toxicity, but supportive care can help manage the symptoms. This includes intravenous fluids, medications to control seizures, and, in some cases, activated charcoal to reduce further absorption of the drug.

What Dog Breed is Ivermectin Toxic to?

Certain dog breeds, particularly those with a genetic mutation in the MDR1 (multi-drug resistance gene), are more susceptible to ivermectin toxicity. These breeds include:

• Collies
• Australian Shepherds
• Old English Sheepdogs
• Shetland Sheepdogs
• Border Collies

Dogs with the MDR1 mutation cannot properly process ivermectin, causing the drug to accumulate in the brain, leading to toxicity. Genetic testing is available to determine whether your dog carries the MDR1 mutation.

What is an Alternative to Ivermectin for Dogs?

Several alternatives to ivermectin are available for dogs, especially for those with sensitivities or breed-related risks. These include:

Milbemycin oxime:
A common alternative, often used in heartworm preventatives like Sentinel, which can also treat intestinal parasites and mites.

Selamectin:
Found in products like Revolution, this drug is effective against a broad range of parasites, including fleas, ear mites, and heartworms.

Moxidectin:
Another macrocyclic lactone, moxidectin is used in heartworm preventatives and can be safer for dogs with ivermectin sensitivity.

What Medications Cannot Be Taken with Ivermectin?

Certain drugs should not be used in conjunction with ivermectin due to the risk of dangerous interactions. These include:

Spinosad:
Found in flea preventatives like Comfortis, spinosad has been shown to increase the risk of ivermectin toxicity.

Ketoconazole:
This antifungal medication may slow down the metabolism of ivermectin, increasing the risk of overdose.

Benzodiazepines:
Drugs such as diazepam can potentially enhance the sedative effects of ivermectin, leading to central nervous system depression.

Conclusion

Ivermectin is a versatile and widely used medication for preventing and treating parasitic infections in dogs. When used correctly, it is highly effective in managing heartworm, mange, ear mites, and other parasitic infestations. However, it’s crucial to follow veterinarian guidance for dosage and administration, as the drug can be toxic in higher doses or to certain dog breeds. Understanding the risks and benefits of ivermectin, along with available alternatives, will help you make informed decisions for your dog’s health.

If you suspect ivermectin toxicity or your dog belongs to a high-risk breed, contact your veterinarian immediately. Always consult a vet before starting or changing your dog’s parasitic treatment plan to ensure safety and effectiveness.