What is the onset and duration of thiamine (Vitamin B1) deficiency?

From the Guidelines

Thiamine (vitamin B1) begins to work within hours after administration, with noticeable clinical improvement often seen within 24 hours in cases of severe deficiency like Wernicke encephalopathy, as supported by the most recent guideline from 2022 1. For oral supplementation in less severe deficiency states, therapeutic effects may take several days to weeks to become apparent. The duration of thiamine therapy depends on the clinical scenario:

• Acute deficiency conditions like Wernicke encephalopathy require immediate IV thiamine,
• Chronic deficiency or maintenance therapy in at-risk individuals (alcoholics, malnourished patients) typically involves oral thiamine at a dose of 100mg daily, as recommended by the ESPEN micronutrient guideline 1. Thiamine works rapidly because it's essential for carbohydrate metabolism and neural function, serving as a cofactor for enzymes involved in the Krebs cycle and pentose phosphate pathway. The body stores only small amounts of thiamine (30-50mg), which can be depleted within 2-3 weeks of inadequate intake, making prompt replacement crucial in deficiency states to prevent permanent neurological damage, as emphasized in the British Obesity and Metabolic Surgery Society guidelines 1. Key considerations for thiamine administration include:
• Route of administration: IV for acute deficiency, oral for chronic deficiency or maintenance therapy
• Dose: varies by clinical scenario, with higher doses for acute deficiency and lower doses for maintenance therapy
• Duration: depends on the clinical scenario, with indefinite continuation of maintenance therapy in at-risk individuals. The most critical aspect of thiamine therapy is prompt initiation in cases of suspected deficiency, as delayed treatment can lead to permanent neurological damage, highlighting the importance of awareness among healthcare professionals, as noted in the ESPEN micronutrient guideline 1 and the British Obesity and Metabolic Surgery Society guidelines 1.

From the FDA Drug Label

CLINICAL PHARMACOLOGY: ... Metabolism is rapid, and the excess is excreted in the urine. ... Absorption of thiamine following IM administration is rapid and complete. The onset of thiamine is rapid. The duration of thiamine cannot be determined from the information provided. 2

From the Research

Onset and Duration of Thiamine Deficiency

• The onset of thiamine deficiency can vary depending on several factors, including the severity of malnutrition, alcohol consumption, and individual susceptibility 3.
• Studies have shown that thiamine deficiency can occur in as little as 14 days of alcohol intake, with symptoms of Wernicke's encephalopathy appearing in 11% of patients hospitalized for alcohol withdrawal symptoms 3.
• The duration of thiamine treatment is not well established, but it is recommended to continue treatment until symptoms resolve, which can take several days to weeks 4, 5.

Thiamine Supplementation Regimens

• Various thiamine supplementation regimens have been employed, with doses ranging from 100 to 1500 mg intravenous thiamine and up to 300 mg intramuscular thiamine 4.
• There is no apparent difference in patient outcomes with different dosing strategies, and all patients who received thiamine experienced symptom improvement 4.
• Parenteral thiamine is recommended for patients with confirmed alcohol-induced Wernicke's encephalopathy, with a dose of ≥100 mg 4, 6.

Risk Factors for Thiamine Deficiency

• Risk factors for thiamine deficiency include malnutrition, refeeding syndrome, gastrointestinal surgery, and alcoholism 7.
• Patients with alcohol use disorders are at higher risk of developing thiamine deficiency and Wernicke's encephalopathy, with 36% of patients having risk factors for Wernicke's encephalopathy 6.
• Education is needed to enhance thiamine prescribing and evaluation of risk factors for Wernicke's encephalopathy in patients with alcohol use disorders 6.