THM 1) Considered the initial drug of choice for overweight diabetics, metformin can also be the starting drug for lean diabetics.
THM 2) Do not start metformin in newly detected diabetics if they are actively losing significant weight.
THM 3) Metformin can be combined with all other anti-diabetics including the other insulin sensitizers, the glitazones.
THM 4) Metformin should be given cautiously at serum creatinine of 1.5 or more to avoid chances of lactic acidosis.
THM 5) Diarrhea due to metformin is dose dependent. Sustained release preparations reduce incidence of diarrhea though the incidence of dyspepsia remains the same.
THM 6) If a patient on metformin develops acute infective gastroenteritis, it should be temporarily withheld.
THM 7) Metformin should be withheld for one day prior to & for two further days after a contrast CT scan.
THM 8) When you initiate a patient of OHA failure on insulin, the one drug that you should logically not remove from the existing prescription is metformin.
THM 9) Metformin administration causes vitamin B12 deficiency. Hence patients on metformin should be supplemented with vitamin B12 especially if they are vegetarian.
THM 10) Do not exceed the daily dose of 2 gm.
THM 11) Metformin is not approved as weight loss drug in non diabetic obese patients.