Possible Interaction: Metformin and Vitamin B 12

“OBJECTIVE Of patients who are prescribed metformin , 10-30% have evidence of reduced vitamin B12 absorption.”

“In conclusion, metformin treatment increased tHcy levels and decreased levels of vitamin B12 and folate.”

“It is known that the metabolism of homocysteine (Hcy) depends on the vitamins B6, B12 and folate, and furthermore that metformin reduces serum vitamin B12 levels.”

“Although vitamin B12 malabsorption is relatively common with long-term metformin treatment, we think this is the first reported case of megaloblastic anaemia.”

“The absorption of folic acid and vitamin B12 is importantly decreased by the prolongued use of metformin , which is the first choice drug in uncomplicated diabetes, thus these two nutrients have been found deficient in the disease and most probably need to be supplemented regularly.”

“ Metformin interferes with mucosal-cell intracellular calcium handling, thus disrupting calcium-dependent absorption of vitamin B12 in the ileum (30).”

“Ten percent to 30% of patients receiving long-term metformin therapy develop vitamin B12 malabsorption, as indicated by decreased concentrations of total vitamin B12 and its bioavailable form, holotranscobalamin (2, 30).”

“Spearman’s correlation showed a significant negative correlation between cobalamin and increased dose of metformin and a significant positive correlation between TCSS and increased dose of metformin.”

“Patients taking doses of metformin more than 1000 mg had lower levels of vitamin B12.”

“Patients taking doses of metformin more than 1000 mg had lower levels of vitamin B12.”

“It has been reported that long-term metformin use might reduce serum vitamin B12 levels.”

“Second, we would like to caution that metformin reduces intestinal absorption of vitamin B12 in up to 30% of metformin‐treated patients and lowers serum vitamin B12 concentrations by 5% to 10%.”

“ Metformin can decrease vitamin B12 and folate concentrations.”