What It Is:
Ivermectin is a broad spectrum antiparasitic medication used in cats to treat and prevent a variety of external and internal parasites. It belongs to the macrocyclic lactone class and works by paralyzing and killing parasites through disruption of their nervous system.
While ivermectin is widely used in many species, its use in cats is off label and must be prescribed and dosed carefully to avoid toxicity.
🐾 What It Treats
Ivermectin is used for:
- Ear mites (Otodectes cynotis)
- Notoedric mange (Notoedres cati)
- Demodectic mange in some cases
- Lice infestation
- Cutaneous larval migrans (hookworm larvae in the skin)
- Heartworm prevention in combination products (off label)
- Other off label parasite control as directed by a veterinarian
It is not effective against tapeworms or most protozoal infections.
🧪 How It Works
Ivermectin binds to glutamate gated chloride channels in parasite nerve and muscle cells, causing:
- Increased chloride ion influx
- Hyperpolarization of cell membranes
- Paralysis and death of the parasite
Because mammals have different receptor sensitivity, ivermectin at proper doses is safe for cats, but overdoses can cause severe neurological signs.
🐾 Dosage and Administration
Ivermectin must be prescribed by a veterinarian. It is available as:
- Oral tablets or liquid (compounded)
- Topical spot on formulations (in combination products)
- Injectable formulations (used carefully and rarely)
Typical off label oral dosing for ear mites or mange is 0.2 to 0.4 mg per kg given once, then repeated two weeks later. For prevention products, dosing and schedule vary by product and parasite risk.
Always follow your vet’s exact dosing schedule and formulation guidelines.
🔍 Side Effects and Precautions
Ivermectin can cause side effects, especially if overdosed or in sensitive breeds:
- Neurological signs such as ataxia, tremors, or seizures
- Lethargy or weakness
- Hypersalivation or vomiting
- Muscle tremors
- Coma in severe overdose
Use with extreme caution or avoid in cats with:
- Hepatic or renal disease (reduced drug clearance)
- Sensitivity to macrocyclic lactones
- Concurrent medications that inhibit ivermectin metabolism
Immediate veterinary care is required if signs of toxicity appear.
🩺 Prognosis
When used correctly under veterinary supervision:
- Most infestations resolve after one or two doses
- Side effects are rare at therapeutic doses
- Overdose can be life threatening and requires prompt treatment
Your vet may recommend follow up exams to ensure parasite elimination and monitor for adverse effects.
💡 Cat Owner Note
Ivermectin is a powerful antiparasitic that can help control stubborn mites or prevent heartworm, but it has a narrow safety margin in cats. Always use a veterinary prescribed formulation and dose, and never use products made for other species without explicit instruction. With proper use, it can be a highly effective part of your cat’s parasite control plan.
❓ Frequently Asked Questions About Ivermectin for Cats
Can I give my cat horse ivermectin paste?
No. Horse products are often too concentrated and can lead to severe toxicity. Always use a veterinary formulation.
How quickly does ivermectin work for mites?
Ear mites and mange often improve within seven to fourteen days of treatment, with follow up dosing as needed.
Is ivermectin safe for kittens?
Use with caution. Young kittens may be more sensitive and require dose adjustments.
What if my cat shows tremors after ivermectin?
Contact your vet immediately. Early intervention can prevent severe neurological damage.
Can ivermectin treat tapeworms?
No. Ivermectin is not effective against tapeworms. Use a specific dewormer for tapeworm control.
Do I need to retreat for mites?
Yes. A second dose two weeks after the first is common to eliminate all life stages of mites.