Excessive alcohol consumption, antibiotics, antiacne drugs, antiretrovirals, antigout drugs, antihypertensives, anti-TB drugs, antiulcer drugs, biguanides, histamine, OCs, PPIs, sulfonamides, tetracyclines & epilepsy medications can deplete vit B12
levels. 5-fluorouracil competitively inhibits the phosphorylation of thiamine to thiamine pyrophosphate thus, inactivates thiamine. Increased excretion of thiamine w/ loop diuretics eg, furosemide; reduced dopa effect of L-dopa w/ vit B6
. Increased vit B6
requirement w/ pyridoxine antagonists eg, INH, hydralazine, D-penicillamine, cycloserine. Enhanced thiamine degradation w/ beverages containing sulphite eg, wine. Increased efficiency of chemotherapeutic drugs w/ α-lipoic acid.