My mum has been type 2 for 30+ years and well controlled apart from when she has a cold etc when b.s levels raise to about 13- 15 Her normal levels are about 3.0 upon waking and 10 ish during the day, but she has been on Digoxin 125mg for past 3 weeks for atrial fibulation and b.s levels are now 10 + on waking up and around 16+ during the day. Her doctor says that the new meds are not responsible and wants to increase her metformin saying it's no longer effective for her, Is he right?