There are a few things always suggested to consider, and that is injection schedule, i.e, frequency,
needle size. I did not consider this very well myself because I was too focused on choosing the right med. What I learned is all you can do is pick one best you can and give it a try. The main ones have proven equal affectiveness, but bear in mind what works for one, may not work for another. So, knowing this, you can always switch.