Hello,my name is***** and I have over 20 years of experience as a veterinarian. I understand that you would like to know the effects of a 300mg Gabapentin capsule on a 15 pound dog.Gabapentin is used in dogs as an anticonvulsant and to treat neuropathic pain. A usual dose is 10mg to 30mg per kilogram (2.2 pounds) of body weight every 8-12 hours.15 pounds is 6.81kgs, so a usual dose for a 15 (6.81kg) dog would be 68mg to 204mgs.While 300mgs is a higher than usual dose this drug is not highly toxic
for a normal, healthy, young dog with properly functioning kidneys. Possible effects from more likely to less likely would be lethargy, sleepiness, incoordination/dizziness, possible vomiting and diarrhea. In most cases with dogs taking a higher than usual dose we can confine them, let them sleep it off and they should be back to normal in 24 hours or so.Certainly if this just occurred and there are no effects yet we can induce vomiting by giving 1 tablespoon of 3% hydrogen peroxide with a little ice cream or bread chunks, then running him around to get the peroxide bubbling in the stomach
to induce vomiting. If no vomiting in 10 minutes repeat once.We do want to make sure that this was not a formulation with added xylitol. That artificial sweetener is toxic for dogs, causing very low blood sugar, liver failure, coma and possible death
and those formulations necessitate a trip to the emergency clinic.Please let me know if you have any further questions.