Thiamine and Other Supplements

Thiamine supplements are recommended for all people undergoing alcohol withdrawal (see ‘Wernicke–Korsakoff’s syndrome’ below). For patients with no clinical features of Wernicke’s encephalopathy or memory impairment, thiamine is recommended as a prophylactic measure. The evidence base to guide dosing is limited with no new trials in recent years. 

The dose, route and duration of thiamine administration depend on the patient’s nutritional status. For example, healthy patients with good dietary intake may be administered oral thiamine 300 mg per day (100 mg three times daily for 3 to 5 days, and maintained on 100 mg oral thiamine for a further 4 to 9 days (for a total of 1 to 2 weeks of oral thiamine). Intestinal absorption of oral thiamine supplements is slow and may be incomplete in patients with poor nutritional status, hence: 

• People with chronic alcohol use with poor dietary intake and general poor nutritional state should be administered parenteral thiamine doses. The recommended dose of thiamine is 300 mg intramuscularly or intravenously per day for several days, and subsequent oral thiamine doses of 300 mg per day for several weeks. 
• Alcohol is associated with thrombocytopenia and coagulopathy that may render intramuscular injection unsafe. 

Parenteral carbohydrates can cause rapid utilisation of thiamine in peripheral tissues and precipitate Wernicke’s encephalopathy (WE).  

• Thiamine (oral or intramuscular) should be given before any carbohydrate load (for example, intravenous glucose) when feasible or otherwise as soon as possible. 

Deficiencies of other B-complex vitamins, vitamin C, zinc and magnesium are not uncommon and an oral multivitamin preparation can be given to nutritionally depleted patients for several days. Consider parenteral magnesium replacement when IV thiamine is used as described above. Oral thiamine supplementation should be continued indefinitely in an alcohol dependent patient who continues to drink alcohol.