If you are talking about the premiums you paid every month, then it is a medical expense. You would report the total you paid during the year.
This is providing that your business is not incorporated. If you are talking about expenses that the business paid, then you would claim a deduction on the T2125 form as other expenses. Please see this link from Canada Revenue, it is the guide for self employed tax returns: http://www.cra-arc.gc.ca/E/pub/tg/t4002/t4002-14e.pdf Look at page 27, Private Health Services Plan premiums.
Hope this will help you.