Thiamine Supplementation During Alcohol Withdrawal: Studies Shed Light on Dose, Route, and Relationship With Cognitive Function

Thiamine deficiency can have serious clinical consequences for people with alcohol use disorder, but the role of thiamine supplementation in these patients is not well understood. Two recent non-randomized studies examined the impact of thiamine supplementation on cognitive symptoms among people receiving treatment for alcohol withdrawal.

In the first study (Listabarth et al), researchers from Austria determined thiamine levels and assessed cognitive function at baseline, 1, 2, and 8 weeks after administration of oral or intravenous thiamine in 50 patients undergoing inpatient treatment for alcohol withdrawal. Patients received thiamine orally (100mg 3 times daily for 7 days, followed by 100mg once daily for the duration of the study), with or without preceding intravenous thiamine (100mg 3 times daily for 5 days), according to the patient’s preference and feasibility of intravenous administration.

In the second study (Bonnet et al), German researchers assessed the relationship between thiamine blood level and cognitive function in a prospective 3-week study in 100 patients admitted for inpatient treatment for alcohol withdrawal. All patients in this study received 200mg thiamine per day orally for 14 days.

Thiamine supplementation:

• In both studies, increases were observed in blood thiamine levels (+100.2nmol/l in the first study; large effect size in the second study).
• In analyses adjusted for age and alcohol intake, the first study found no significant difference in blood thiamine levels between people who were administered thiamine orally versus intravenously.

Cognitive function:

• Both studies used the 30-point Montreal Cognitive Assessment (MoCA) to test cognitive function.
• In the first study, the change between baseline and follow-up thiamine levels was associated with improvements in the delayed recall sub-score of the MoCA.
• Over the course of the second study, patients’ MoCA scores improved (medium effect size), with 78 patients having scores indicative of cognitive impairment at baseline, 69 at week 1, and 67 at the end of treatment; the improvement was more pronounced among patients with more severe impairment (i.e., with a MoCA score <20).
  • Of the 27 patients with scores <20 at baseline, 7 had scores <20 at the end of treatment.
  • Baseline thiamine blood level predicted baseline MoCA scores.
• No patients developed Wernicke encephalopathy (WE) during the studies or at follow-up.

Comments: In these two studies conducted among patients without WE, oral and intravenous thiamine supplementation was associated with relevant increases in thiamine blood levels and, in the context of alcohol withdrawal, a positive impact on cognitive function. These results suggest that oral supplementation may be useful among patients at lower risk for WE, although intravenous thiamine supplementation is likely required for patients with WE or at high risk for WE.

Nicolas Bertholet, MD, MSc

References: Listabarth S, Vyssoki B, Marculescu R, et al. Can thiamine substitution restore cognitive function in alcohol use disorder?. Alcohol Alcohol. 2023;58(3):315–323.

Bonnet U, Pohlmann L, McAnally H, Claus BB. Further evidence of relationship between thiamine blood level and cognition in chronic alcohol-dependent adults: prospective pilot study of an inpatient detoxification with oral supplementation protocol. Alcohol. 2023;110:23–31.