hey there, what units is that 340 in? it makes a difference.
what kinds of b12-rich foods do you eat? and how is your potassium intake generally?
to your supplement question it seems that by and large sublingual strips are as good as injections (maybe not in 100% of cases though).
methylcobalamin is a good form to choose for sublingual strips.
hope that helps somewhat anyway, until you post again at least
my approach: no meds so far - just nutrient-dense anti-inflammatory whole foods, and supplements where needed
info: www.whfoods.com, www.nutritiondata.com