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Dr. B.
Dr. B., Veterinarian
Category: Dog Veterinary
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Experience:  Hello, I am a small animal veterinarian and am happy to discuss any concerns & questions you have on any species.
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My 15 lb dog ate a comfortis 20.1-40 lb dog will it hurt

Customer Question

My 15 lb dog ate a comfortis for a 20.1-40 lb dog will it hurt her?
Submitted: 5 months ago.
Category: Dog Veterinary
Expert:  Dr. B. replied 5 months ago.
Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today. How long ago did she have this?
Customer: replied 5 months ago.
2 hrs.
Expert:  Dr. B. replied 5 months ago.
Thank you,Now thankfully the adverse signs for this drug do tend to be mild in cases of overdose as we have here. Specifically, it usually causes lethargy and GI upset with vomiting/diarrhea/appetite loss within 48 hours of ingestion. Though on rare occasions, it is possible to see tremors, seizures and wobbliness for sensitive dogs. Now since Ella had a large dose for her size 2 hours ago, we do need to tread with care. To start, though we are getting to a time frame where benefit will be lessened, we could induce vomiting just now. To induce vomiting at home, you can administer 3% hydrogen peroxide orally at a dose of 1ml per pound. (2 teaspoons per 10 pounds of body weight). You can give it via dropper, syringe, turkey baster – we just want to get it in. After giving this orally, move the abdomen around or get your wee one walking about to get things mixing. This should usually lead to vomiting. If it is unsuccessful after 10 minutes then it can be repeated twice more. And if we still have no vomiting, then you'd need to consider seeing your local vet (or ER vet) so that apomorhpine (a very strong injectable emetic) can be administered just get this out of the stomach and avoid any adverse issues. As well or alternatively (since we have an 8 hour window of effect with this), you can also use activated charcoal at this stage. This is available over the counter from the pharmacy (ask for the high strength version in grams, not the one for gas since you will need a lot of these) and works by binding any remaining material in the stomach. For activated charcoal, we tend to give 1-4 grams per pound every 8 hrs. This can be mixed with food to be fed or with water to syringe feed (do note that it stains, so keep it away from white carpets/clothes). This will just limit how much is absorbed and reduce the intoxication risk here. Finally, whichever we use or if we just monitor, we do want to try to address any potential GI upset here for the next 24-48 hours. To do so, you can consider offering a light diet option for a few days. Examples of an easily digestible diet include cooked white rice with boiled chicken, boiled white fish, scrambled egg, or meat baby food (as long as its free from garlic or onion powder). Ideally, we want to offer this as small frequent meals to keep the stomach settled. Further to this, if we see any hints of nausea, then we can also treat with an OTC antacid like Pepcid (More Info/Dose @ or Zantac (More Info/Dose @ These are usually given 20 minutes before offering food to allow absorption and of course you want to double check with your vet before use if your wee one has any know health issues or is on any medications you haven't mentioned. Overall, Ella has had a large dose but GI upset is most likely from this. So, we can use the above just now to limit the dose she had. Otherwise, we can choose to monitor, use the above to soothe her stomach, but plan to see her vet if she has a very upset stomach or we see any of those more serious signs for her. Just in case you need a local emergency vet, you can check @ or via Please take care, Dr. B. -----------------------------------------------------------------------------------------------------------------If you have any other questions, please ask me – I’ll be happy to respond. Please remember to rate my service once you have all the information you need as this is only way I am credited for helping you. Thank you! : )
Customer: replied 5 months ago.
She seems to be handling the comfortis without any upset at present. Do you think it would be ok to just monitor. If seizure or tremors occur how will they effect her in the short and long term
Expert:  Dr. B. replied 5 months ago.
Hi again,I am glad to hear that she is well just now, though as I noted it can be a delayed onset for our adverse effects. So, monitoring needs to be continued for the next few days. Otherwise, neurological signs like those I noted won't tend to have long term effects but seizures can obviously can be risky in the short term if she were sensitive and had one in response to this. Especially as severe ones can cause brain damage if not treated. Though again those are rarer signs and we'd hope not to see them here.All the best,Dr. B.-----------------------------------------------------------------------------------------------------------------If you have any other questions, please ask me – I’ll be happy to respond. Please remember to rate my service once you have all the information you need as this is only way I am credited for helping you. Thank you! : )
Customer: replied 5 months ago.
My daughter has her at present would the charcoal help if we have to wait to give it to her after 9 hours from ingestion?
Customer: replied 5 months ago.
Other issue in the long-term is that poor Ella is being devoured by fleas. So if we do the charcoal will what she has suggested so far help her situation and/or how long will we have to wait to retreat her I'm assuming 30 days?
Customer: replied 5 months ago.
I've been to CVS & Walgreens and they only have charcoal capsules with 250mg per no extra strength. I guess we will have to watch her and wait it out.
Expert:  Dr. B. replied 5 months ago.
Hi again,Nine hours would be too.late to be of benefit. So I'd skip them if you couldn't dose her sooner. Though to note, we can use the milligrams version but would need to open a lot of capsules to get a proper dose to syringe. Otherwise redosing would be in a months time. Take care,Dr. B
Customer: replied 5 months ago.
How many milligrams should I give her per pound?
Customer: replied 5 months ago.
If I give it to her within the 8 hours will what she has ingested so far be of benefit to her combating the fleas?
Expert:  Dr. B. replied 5 months ago.
Hi again,It will likely still be effective. Otherwise, she needs at least 60 of those low dose capsules opened to mix with water for stringing to absorb what is left.Take care,Dr. B
Expert:  Dr. B. replied 5 months ago.
Hi Melinda,

I'm just following up on our conversation about Ella. How is everything going?


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