Thiamine

How it works

As the cofactor thiamine pyrophosphate, it is essential for carbohydrate metabolism, supporting enzymes such as transketolase and pyruvate and alpha-ketoglutarate dehydrogenases.

Prescribing in practice

• In suspected Wernicke's encephalopathy, give parenteral thiamine before or alongside any intravenous glucose, since glucose given first can precipitate or worsen the condition.
• Anaphylaxis can rarely occur with intravenous administration, so give it with appropriate observation and resuscitation facilities available.
• High-dose parenteral replacement is preferred for treatment of established deficiency, with oral therapy used for maintenance or milder deficiency.

Monitoring

Monitor clinical response, particularly neurological status in Wernicke's encephalopathy, rather than routine blood levels.

Counselling the patient

• Replacement corrects a vitamin deficiency and is important if your diet has been poor or with heavy alcohol use.
• Report any rash or breathlessness during an injection immediately.
• Continue treatment for the full course advised, even once you feel better.

Evidence & guidelines

Thiamine is the established treatment for thiamine deficiency, and giving it before glucose in suspected Wernicke's encephalopathy is standard guidance.