Welcome to Justanswer! I am Dr. Altman and happy to assist you both today
If your dog ingested this within the last hour then you can induce vomiting with 3% hydrogen peroxide 1 tsp per ten pounds (2 tsp for Tubby) then walk around to mix it in the stomach and agitate the lining. If no vomiting within 10-15 minutes it can be repeated once only in hopes of inducing vomiting.
Overall, "statin" medications such as Pavastatin are reported to have a very wide margin of safety for an acute overdose.
In situations such as this, clinical signs are reported to be limited to stomach upset and potentially flatulence.
As far as metformin, this is not a drug used in dogs and thankfully this does not increase insulin production in the pancreas and rarely causes hypoglycemia.
The most commonly seen effects of this drug is digestive upset including vomiting and diarrhea, however hypothermia, hypotension, pale mucous membranes, and hindlimb tremors are also possible. Because this can effect the body temperature and blood pressure it is best to have them monitored by a vet and IV fluids administered to flush the drug form the system.
If possible I would suggest having her seen by a vet if you choose to monitor at home and she becomes lethargic, has muscle tremors or shaking or her gums become pale, white or blue in color she should be seen immediately.
Here is information on overdose of this drug.
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