Thiamine is specifically used in the treatment of the various manifestations of thiamine deficiency such as Beriberi and Wernick's encephalopathy, neuritis associated with pregnancy and pellagra. Supplementary Thiamine may be indicated prophylactically in conditions where there is low dietary intake or impaired gastro intestinal absorption of thiamine (e.g. alcohol) or where requirements are increased (pregnancy, carbohydrate rich diet).
There is no absolute contraindication but the risk of anaphylaxis is increased by repeated parenteral administration. Mild allergic phenomena, such as sneezing or mild asthma are warning signs that further may give rise to anaphylactic shock. To avoid this possibility it is advisable to start a second course of injection with a dose considerably lower than that previously used. Because of the above, vitamin B1 injection should not be given intravenously except in the case of comatose patients. Once thiamine deficiency is corrected there is no need for parenteral administration or for the administration of amounts in excess of daily requirement.
Vitamin B1 does not have adverse effects when given orally, but in a few fatal cases anaphylactic reactions have occurred after intravenous administration of large doses (400 mg) in sensitive patients, especially children, and in one case following an intramuscular dose of 125 mg. The risk of such reactions increases with repeated administration of the drug by parenteral route. Transient mild soreness may occur at the site of intramuscular administration
The drug may be given safely to neonates, children, pregnant and lactating women and elderly patients.
Vitamin-B preparations
Thiamine injection should be protected from light and moisture.