I am most interested in the preparation of the pen before giving the shot to my husband. I know that I have to shake the pen to make sure the solution is thoroghly mixed. After the needle is attached, I have been flicking the vial to make sure all air bubbles go to the top and then I release 2 units into the air. Now I click the dosage units to the prescribed amount and inject the insulin. It is the 2 pre-injection units that I am questioning. This reduces the amount of insulin available to meet the 90-day supply. Should I be releasing 2 units before each shot? Or is that only for the initial shot given at the first use of each pen? Or should I be releasing only 1 unit to get rid of any air bubbles?