Amoxicillin should be considered a general, all purpose antibiotic. Not only is it affordable, but obtaining a prescription for your dog is easy, and the medication almost always works. Generally, 10 mg of amoxicillin is prescribed for each pound a dog weighs. So, if your dog weighs 10 pounds, it would be given 100 mg's of Amoxicillin every eight-to-12 hours, depending on the severity of the ear infection.