Thiamine Administration Protocol
For suspected or confirmed thiamine deficiency, administer 100-300 mg thiamine intravenously daily for acute deficiency, while for mild deficiency, 10 mg/day orally is recommended. 1
Route of Administration
- For acute thiamine deficiency or Wernicke's encephalopathy, intravenous (IV) administration is preferred at 100-300 mg/day 1
- For emergency/intensive care patients, administer 100-300 mg/day IV for 3-4 days from admission 1
- For suspected Wernicke's encephalopathy, higher doses of 500 mg three times daily IV are recommended 1, 2
- For mild deficiency without acute symptoms, oral administration of 10 mg/day for one week, followed by 3-5 mg/day for at least 6 weeks is appropriate 1
- For patients with alcohol-related gastritis or malabsorption, IV route is preferred due to poor absorption 1
Timing Considerations
- Thiamine should always be administered before any glucose-containing IV fluids to avoid precipitating acute thiamine deficiency 1, 3
- For patients at risk of refeeding syndrome, administer 300 mg IV before initiating nutrition therapy, then 200-300 mg IV daily for at least 3 more days 1
Duration of Treatment
- For mild deficiency, treatment should continue for at least 6 weeks 1
- For alcoholic liver disease with withdrawal symptoms, continue treatment for 2-3 months 1
- For Wernicke's encephalopathy, treatment with high-dose thiamine (≥500 mg) should be administered for at least 3 days 2
Special Clinical Scenarios
- For prolonged vomiting or dysphagia with risk of thiamine deficiency, administer thiamine 200-300 mg daily with vitamin B compound strong (1-2 tablets three times daily) 4
- For patients undergoing bariatric surgery with neurological symptoms, immediate thiamine supplementation is critical 4
- For patients on total parenteral nutrition (TPN), thiamine must be included to prevent deficiency, even if oral multivitamins are prescribed 5
Monitoring
- Measure thiamine status by assessing red blood cell or whole blood thiamine diphosphate (ThDP) levels 1
- Monitor patients with suspected deficiency who have cardiomyopathy, are on prolonged diuretic treatment, receiving medical nutrition, post-bariatric surgery, at risk of refeeding syndrome, or have encephalopathy 1
Safety Considerations
- Thiamine has an excellent safety profile with no established upper limit for toxicity 1
- High IV doses rarely cause anaphylaxis; doses >400 mg may occasionally induce nausea, anorexia, and mild ataxia 1
- For patients with alcohol use disorder in the community setting, intramuscular thiamine 250 mg daily for 3-5 days is recommended during detoxification 6
Common Pitfalls and Caveats
- Failure to administer thiamine before glucose-containing solutions can precipitate or worsen Wernicke's encephalopathy 4, 1
- Oral thiamine may be inadequate in patients with malabsorption or severe vomiting 3
- Thiamine deficiency should be considered in all critically ill patients, particularly those with unexplained lactic acidosis, heart failure, delirium, or neuropathy 7
- The classic triad of Wernicke's encephalopathy (ophthalmoplegia, ataxia, and confusion) may not be fully present in all patients, making diagnosis challenging 8
- In alcoholics, the clinical diagnosis of Wernicke's encephalopathy requires two of the following: dietary deficiencies, eye signs, cerebellar dysfunction, or altered mental state/memory impairment 8