Hello & welcome Joan. I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
First, take a deep breath. Metformin isn't a drug that we use often in veterinary medicine but it is one that is used in dogs on occasion. Therefore, this isn't an outright toxicity. Furthermore, the dose we use in dogs tends to be 250-500mg. So, even if she has ingested this, it is a high end normal dose for a dog (though of a drug not appropriate for her system).
Now if Poppie has potentially ingested this tablet less then 2 hours ago, then inducing vomiting can still have some benefit with this type of medication.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 -- just we want to give it orally and get into her. After giving this orally, move the abdomen around or get her to walk about to get things mixing. This should usually lead to vomiting. If it is unsuccessful after 10 minutes then it can be repeated once more. And if we still have no vomiting, then we might want to consider seeing the ER vet so that the vet can administer apomorhpine (a very strong injectable emetic) to get the tablet back. After inducing vomiting (or sometimes in place of this), we will use activated charcoal to ensure we limit drug absorption. (More Info/LINK). So, these will still be of benefit at this stage.
Now in regards XXXXX XXXXX effects from absorption, the time frame for seeing signs does vary dog. Reports have noted seeing GI upset (vomiting being the most common adverse sign) start within 15 min up to 8 hours post ingestion. Therefore, we may not see signs at this stage but still could see them in the hours to come. Besides vomiting, we can see lethargy, anxiousness, rapid shallow breathing, diarrhea, low blood pressure, pale gums, fast heart rate, and tremors of the hind leg. These signs can last anywhere from 18-24 hours.
Overall, if you are fairly sure she has ingested this tablet, then it'd be worth considering inducing vomiting to limit the absorption of this tablet. If you are not sure and want to monitor her for signs, then the above should be watched for. In either case, since nausea and vomiting are the most common effects of this drug, you can consider starting her on an antacid to keep her stomach as settled as possible. There are a number of antacids that are available over the counter and pet friendly. I would advise only treating with one, but the two I tend to use are Pepcid (LINK) or Zantac (LINK) These are usually given 20 minutes before food (to allow absorption) and of course you want to double check with your vet if Poppie has a pre-existing condition or is on any medications. Furthermore, you can consider feeding small, frequent meals of a light diet (ie boiled chicken or white fish with rice or scrambled egg) to keep her stomach settled.
And just to note if you do want to have her seen today, I wanted to mention that most veterinary practices here do have contingency plans for emergency care for their patients. This means that if you ring the practice, they will likely have a message to direct you on how to contact their emergency service. And if you don't have a vet you can find one local to you, you can check RCVS register (LINK). or you can check here to find your local Vets Now (LINK) who are open all nights/weekends.
I hope this information is helpful.
If you need any additional information, do not hesitate to ask!
All the best,
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