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Dr. Michael Salkin
Dr. Michael Salkin, Veterinarian
Category: Dog Veterinary
Satisfied Customers: 30418
Experience:  University of California at Davis graduate veterinarian with 45 years of experience
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My pug had her flea medicine- simparica - dose 3 days ago

Customer Question

My pug had her flea medicine- simparica - dose 3 days ago and today she ate the great dane's dose----- so a 88-132 pound dose... I cannot find what to do...
JA: I'm sorry to hear that. The Expert will know if your Great Dane will be able to digest that. What is the Great Dane's name?
Customer: It's the pug that took the additional dose.. Her name is hazel
JA: Is there anything else the Veterinarian should be aware of about Hazel?
Customer: Only that she took 4 times her weight of the medicine
Submitted: 2 months ago.
Category: Dog Veterinary
Expert:  Dr. Michael Salkin replied 2 months ago.

You're speaking to Dr. Michael Salkin. Welcome to JustAnswer. I'm currently typing up my reply. Please be patient. This may take a few minutes.

Expert:  Dr. Michael Salkin replied 2 months ago.

Here's what you need to know: In a margin of safety study, Simparica was administered orally to 8 week old Beagle puppies at doses of 0, 1, 3, and 5 times the maximum exposure dose of 4 mg/kg at 28 day intervals for 10 doses. No adverse effects were observed at the maximum exposure dose of 4 mg/kg. In the overdose groups, transient and self-limiting neurological signs were observed in some animals: mild tremors at 3 times the maximum exposure dose and convulsions at 5 times the maximum exposure dose. All dogs recovered without treatment.

A 4 times overdose, then, might cause tremors but not convulsions. If she ingested that dose within a couple of hours it would be prudent to induce emesis with 3% hydrogen peroxide dosed at 5 mL (one measuring teaspoon) per 5 lbs of body weight. She should vomit within 15 minutes. If not, please repeat the same dose. Please respond with further questions or concerns if you wish.

Customer: replied 2 months ago.
If she doesn't vomit after 2 doses.... Do I do anything further??
Expert:  Dr. Michael Salkin replied 2 months ago.

No, you'll have irritated her stomach lining enough and so more peroxide is more harmful than helpful. Remember, all dogs - even those that convulsed recovered without treatment. How much does she weigh, please? I might be able to prognose better if I can determine her mg/kg dose she ingested.

In dogs neurological effects were noted at doses of 20 mg/kg (convulsions, tremors and ataxia) and 12 mg/kg (tremors, ataxia). Signs appeared to occur primarily in the first 24 hours after dosing and resolved without treatment. No effects on the nervous system were observed in any animal at 4 mg/kg.

Customer: replied 2 months ago.
She weighs 16 pounds and took her pill of 11.1-22.0 3 days ago. Today snagged the Dane's pull of 88.1-132.0 punds
Customer: replied 2 months ago.
Customer: replied 2 months ago.
The Dane's pill of 88.1-132.0 pounds
Expert:  Dr. Michael Salkin replied 2 months ago.

Thank you. That's a total of 140 mg within 3 days which is equivalent to 19.4 mg/kg - very close to the dose that can cause convulsions and expected to at least cause tremors and ataxia ("drunken sailor"). There's no specific antidote. Treatment consists of decontamination by emesis and then administration of activated charcoal (stomach tubed by a vet) and then any neurologic symptoms are treated with benzodiazepines or anticonvulsants as need be. I would admit Hazel to a 24-hour facility if possible. Her prognosis is good treated or not but she could be treated in a manner in which serious symptoms shouldn't arise. Please continue our conversation if you wish.