Currently, there are no approved algorithms for correction of vitamin B12 deficiency (vit. B12) in individuals with type 2 diabetes mellitus (T2DM) receiving metformin. At the same time, a large number of scientific works are devoted to different schemes for correcting this condition and methods of administering vit. B12 medications. In addition, a series of studies demonstrated the importance of optimal dosing of vitamin B12 medications due to the possible association of vit. B12 high doses with risk of cancer development.
OBJECTIVE
To study the correlations between dosing regimen, biochemical markers of vit. B12 status in the blood, clinical symptoms dynamics while using a standard daily high-dose oral therapy or high-dose once-weekly therapy in patients with type 2 diabetes mellitus receiving metformin.
MATERIALS AND METHODS
The research included 60 patients with T2DM (32 men (53.3%), 28 women (46.7%), mean age 52.8±9.8 years, T2DM duration from 4 months to 24 years) and detected deficiency of vitamin B12 and/or holotranscobalamin (holo-TC) in addition to metformin administration. Patients were randomized into 2 groups in order to receive cyanocobalamin orally at a dose of 1000 mcg daily for 8 weeks (the 1st group) or 1000 mcg once weekly for 16 weeks (the 2nd group).
RESULTS
Application of each of the two cyanocobalamin dosing schedules led to increased level of vitamin B12 in the blood. However, vitamin B12 level has increased more significantly and reached the reference value of 695.4 [448; 906.2] pg/ml (>450 ng/l) in patients of the 1st group receiving cyanocobalamin daily at a dose of 1000 mcg over 8 weeks. At the same time, a number of adverse events such as headache, allergic reactions, diarrhea and dizziness has been identified. Patients in the 2nd group who received cyanocobalamin weekly orally at a dose of 1000 for 16 weeks had a lower vit. B12 increase than patients in the 1st group and reached a boundary value of 343.5 [160.7; 585] pg/ml (200 pg/ml<vit. B12<450 pg/ml). Nevertheless, holo-TC level exceeded 50 pmol/l, which allowed to exclude the presence of vit. B12 functional deficiency. There were no adverse events in patients when applying this vit. B12 deficiency correction scheme. In addition, a positive clinical dynamics characterized by reduced neurological symptoms and improved patients’ quality of life has been noted.
CONCLUSION
The study of correlation between dosing schedule, biochemical markers of vitamin B12 status in the blood, dynamics of clinical symptoms has demonstrated the possibility of using high dose of cyanocobalamin once weekly in patients with type 2 diabetes mellitus taking metformin in order to restore vitamin B12 physiological adequacy.
