Loop diuretic therapy, thiamine balance, and heart failure.

Thiamine, or vitamin B1, is a water-soluble B complex vitamin that was first discovered in 1910 in the process of exploring how rice bran cured patients of beriberi. Thiamine is not synthesized in humans, therefore its availability for necessary cellular processes hinges on its continual ingestion. The amount of thiamine one needs to ingest to maintain balance is disease state-dependent or medication-dependent. Severe chronic thiamine deficiency can have significant neurologic and cardiac effects, the latter is reflected in a particular type of heart failure called wet beriberi. This form of heart failure clearly benefits from thiamine supplementation. It is unclear, however, whether thiamine supplementation offers any benefit in other forms of heart failure. Despite this, it is not unreasonable for heart failure patients to routinely ingest a thiamine-containing multivitamin; patients using diuretics have an increased urinary excretion of thiamine and thus are at a higher risk for developing thiamine deficiency. The role of thiamine in heart failure, however, remains arguable.