A great piece on Big Pharma marketing to doctors by John Oliver on his show Last Week Tonight. Big Pharma reps are heavily influencing American doctors (I predict that it is very similar in Canada) to prescribe their medication, not because the drug works but because prescribing the drug comes with a free lunch. I highly suggest you use the website Oliver mentions to see if your doctor receives any rewards/bribes from Big Pharma and/or ask them up front.
As the patient, you DO NOT have to accept the first drug your doctor gives you. You have the right to change a drug, suggest a drug, research a drug for yourself, get a second opinion and SWITCH DOCTORS if it is becoming evident that they are not listening, pressuring you and do not have your best interests at heart. This is not a game, this is your life.