You can always register as a student and take courses as you wish, but it is not a post bac program like in the USA. ie. Medical courses meant to better prepare you for med school or to evaluate you for medical school applications.
In Canada it may be best to do a second Bachelors (2 years long if you can get credit for 2 years from your previous Bachelors. Or you can do a Masters degree and hope that helps you.