Pharmacotherapeutic group: Vitamins, Vitamin B1, plain and in combination with vitamins B6 and B12, Vitamin B1, plain. ATC vet code: QA11DAO1.

Vitamin B1, also known as thiamine and as aneurine, is a water soluble vitamin. Aneurine is converted in the body to aneurine pyrophosphate (cocarboxylate) which acts as a coenzyme for several decarboxylating enzyme systems, the most important of which is decarboxylase. The enzyme is necessary for the decarboxylation of pyruvic acid, an intermediate stage in carbohydrate build-up or breakdown. When carbohydrates are a major source of energy the body requirements of aneurine increase. Deficiencies affect the nervous and gastrointestinal systems and skin.

Tissues dependent on glucose or lactate-pyruvate for energy such as the brain and heart are particularly compromised in thiamine deficiency. Thiamine deficiency may be primary, due to deficiency in the diet, or secondary, because of destruction of the vitamin in the diet by thiaminase. The principal cause of thiamine deficiency is the presence of thiamine-destroying agents which are widely distributed in nature, and produced by rumen microflora. Growing sheep are particularly susceptible, and outbreaks of cerebrocortical necrosis have been associated with sulphur in the diet.