Charged with impaired over 80 in Canada but im a us citizen. (this will be my second offense)
An attorney being admitted to practice in Canada and the US is not that common, and in particular within the criminal defense area due to it's somewhat localized nature. That being said you should probably retain a Canadian criminal defense attorney, hopefully from the area to represent you in a case like this. Their knowledge of the law and the local systems will be the most important attributes.
This answer does not constitute a legal consultation, or definitive answer, nor does it establish a lawyer client relationship. Each case, controversy, or situation is factually different and requires particularized evaluation.