Reduced vit B1
efficacy w/ 5-fluorouracil; beverages containing sulphite eg, wine. Diminished vit B1
uptake w/ antacids; alcohol, black tea. Increased vit B1
excretion in the urine w/ certain diuretics eg, furosemide. Reduced effect of L-dopa w/ vit B6
. Increased vit B6
requirement w/ pyridoxine antagonists eg, INH, hydralazine, cycloserine, D-penicillamine.