My mum's b12 level were at 274 last year, she went on to have a TIA. I think it ws caused by years of taking metformin. Her GP refused to give her trial of b12 injections but gave her a private prescription of 5 viles of b12. My question is, is it safe for her to take b12 with the medication she is currently on? Metformin, omeprezole, clopidogrel are the main ones I'm concerned about. Can she have an adverse reaction does anyone know?