What's a Banana Bag?

The banana bag has been a long-standing treatment for vitamin and electrolyte deficiencies in patients with chronic alcohol use disorder (AUD) admitted to the intensive care unit (ICU). It contains a combination of 100 mg of thiamine, 1 mg of folic acid, 1-2 g of magnesium, and a multivitamin formulation in either normal saline or dextrose in water solution.

It’s unclear whether everything in the banana bag meet the needs of critically ill patients or those with underlying medical conditions, such as Wernicke’s encephalopathy (WE). This was the focus of research published in the August 2016 issue of the Critical Care Medicine Journal, and its findings are essential knowledge for pharmacists as preparations for critically ill patients undergo changes.

Thiamine

This essential vitamin is often low in patients with alcohol abuse histories, and its deficiency can also lead to WE. Usually, WE’s sole symptom is mental status change, a nonspecific marker that’s common in critically ill patients. In addition, much higher thiamine doses are needed to treat or prevent WE compared with what’s needed in other conditions, so the 100-mg dose may be insufficient to treat WE patients and prevent further complications.

Folate

Deficiency of this nutrient is also common in chronic AUD patients. It can lead to psychosis, agitation, and sleep disturbances in high-risk individuals. Intravenous (IV) folate is preferred because oral absorption is decreased in critically ill patients. Thus, IV folic acid at 400 mcg to 1000 mcg is appropriate for these patients.

Magnesium

This mineral plays an important role in most cell processes, including cointeracting with thiamine. Little evidence indicates that magnesium supplementation is important in chronic AUD patients; however, other benefits of magnesium supplementation, such as suppression of cardiac arrhythmias, supports its use in this patient population.

Multivitamin

This provides low doses of daily vitamins that normal patients would need; however, critically ill patients may have more severe vitamin deficiencies that won’t respond to low-dose vitamins. Its use in the banana bag appears to be arbitrary.

Clinicians should choose IV fluids based on the patient’s nutritional status. If a patient is in alcoholic ketoacidosis, then dextrose in water is appropriate. If a patient is dehydrated, however, then normal saline is the better IV fluid.

Chronic AUD patients may be deficient in several vitamins, nutrients, and electrolytes. The banana bag may not provide enough vitamins and nutrients to treat severe deficiencies. Clinicians should treat patients based on their individual nutritional/vitamin needs and give higher doses of many vitamins and minerals in general.