Directions for using ivermectin 1% solution undiluted
If you use ivermectin 1% solution undiluted, the dosage will be higher than is needed for heartworm prevention. This is safe for most dogs, as long as they do not have the MDR1 mutation that causes sensitivity to ivermectin, and as long as the ivermectin is not combined with spinosad, a flea control ingredient used in Comfortis and Trifexis (also called Vethical AcuGuard and ComboGuard). See Ivermectin Sensitivity above for more information.
Ivemectin is given orally (never use pour-on solutions for heartworm prevention).
Dosage using Ivermectin 1% solution undiluted for heartworm prevention: give 1 drop from an eye dropper (one-half of 0.1 cc), assuming 20 drops per ml. Note the number of drops per ml can vary depending on viscosity and temperature, and what is used to create the drop. An eye dropper will product a larger drop than a syringe will. This amount will provide more ivermectin than is needed for heartworm prevention, as follows:
1 cc of ivermectin 1% undiluted contains 10,000 mcg; 0.1 cc = 1,000 mcg, 1 drop = approx 500 mcg ivermectin, assuming 20 drops per ml (approximately what an eye dropper would produce). The exact dosage is 0.00272 ml (approximately 0.003 cc) per 10 pounds of body weight.
The owners were unaware of what had happened until the dogs began to fall ill. Treatment had failed to save the puppy that developed symptoms first. Meanwhile two more had died, and the owners called me out to euthanize the sole remaining puppy that was in a coma. My clients were obviously heartbroken and felt terrible that their puppies had died from a preventable poisoning. Let me take this opportunity to review some basic information about ivermectin. Ivermectin is a member of the macrocytic lactone class of parasiticides. It is commonly used as a heartworm preventative in small animals and for the treatment of certain types of external (e.g., mites) and internal parasites in many different species. The difference between the safe use of ivermectin and poisoning is all about the dose and an animal’s inherent sensitivity to the drug. Some dogs carry a gene (MDR1 or ABCB1) that makes doses of ivermectin and other drugs that are safe for the general population dangerous to those individuals. I’m going to focus on dogs from here on out since they were involved in 282 of the 318 potentially toxic ivermectin exposures reported to the ASPCA Animal Poison Control Center during 2008–2009. Typical doses for ivermectin in dogs are:
Non-sensitive breeds generally need to be exposed to more than 2,000 ug/kg before significant symptoms develop, but the potentially toxic dose in MDR1 positive individuals can be as low as 100 ug/kg. Take note that the incredibly low dose used for heartworm prevention is well below the toxic dose even for even the most sensitive dogs. Before using higher doses of ivermectin, however, at risk dogs can be tested for the MDR1 gene mutation. This is especially important for breeds like Collies, Shetland Sheepdogs (Shelties), Australian Shepherds, Old English Sheepdogs, English Shepherds, German Shepherds, Long-haired Whippets, Silken Windhounds, and mutts that might be derived from these breeds. Animals can absorb ivermectin through oral or topical exposures as well as via injection. Symptoms arise when the drug is present in the body at high enough concentrations that it crosses the blood-brain barrier and adversely affects neurologic function. Typical signs include:
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Treatment for an overdose of ivermectin is essentially symptomatic and supportive. If the poisoning is caught early enough, decontamination is helpful (e.g., washing pets after topical exposure or inducing vomiting and/or activated charcoal administration within a few hours of ingestion). Intravenous fluid therapy, endotracheal intubation, mechanical ventilation, extensive nursing care, seizure control, application of eye lubricants if the patient cannot blink, and nutritional support may all also be necessary. In some cases, intravenous lipid emulsion therapy, which is a new but promising option for certain types of poisoning, might be worth considering. A pet’s prognosis can be quite good if aggressive treatment is initiated in a timely manner, but because severe cases of ivermectin overdose often require several weeks of therapy, the expense is often prohibitive … as was the unfortunate case with my clients who chose to euthanize the last puppy in what had been their much anticipated litter.
Directions for using Ivermectin powder (this product appears to have been discontinued)
Dosage using Ivermectin powder for heartworm prevention (you may want to double these doses for better protection):
5 grams of ivermectin power contains 1,000 mcg ivermectin. The exact dosage is 0.136 grams per 10 pounds of body weight. The company says that 1 teaspoon weighs 5 grams, but people who have weighed a level teaspoon of the powder have found that it weighs 2.8 grams. Based on this information: 1 level teaspoon (2.8 grams) of ivermectin powder contains 560 mcg ivermectin 1/4 tsp (0.7 grams) of ivermectin powder contains 140 mcg ivermectin Give 1/4 tsp per 50 pounds of body weight.
Ivermectin can be used to treat demodectic mange (demodex) and sarcoptic mange (scabies). The dosage is much higher than that used for heartworm prevention, so its important to have an accurate diagnosis prior to treatment, especially for demodex. See Ivermectin Sensitivity above for information on whether it is safe to give these high doses of ivermectin to your dog. Also, one study found that giving oral ivermectin with a fatty meal increases absorption significantly. This could be problematic for dogs getting high doses of ivermectin, as are used to treat mange. It is safer to give away from meals.
How fast does ivermectin work on mange?
How much ivermectin do you give a dog per pound?
For skin parasites, it is 0.15 milligram per pound (0.3 milligram per kilogram) and needs to be repeated after 14 days. For internal worms, the one-time dose is 0.1 milligram per pound (0.2 milligram/kilogram).
How do you use ivermectin for mange?
How often should I treat my dog with ivermectin?