Considerations when administering medications enterally in the critically ill

Enteral administration of medications to critically ill patients may be advantageous to other routes of administration. This review summarizes key considerations for the bedside clinician when medications are administered through enteral access devices (EADs).

Critical illness is associated with gastrointestinal dysfunction that inconsistently affects drug dispersion and absorption and may enhance or reduce bioavailability. Other factors such as the first-pass metabolism, microbiome alterations and the concomitant use of other medications (vasopressors, acid suppressants) may influence drug absorption. Concurrent administration of medications with enteral nutrition is fraught with potential errors. Drug-nutrient and drug-drug interactions may lead to tube occlusion. Although liquid formulations of medications are preferred over solid dosage forms for EAD administration, they may be hyperosmotic or contain sorbitol to cause gastrointestinal disturbances. The size and placement of the EAD tube may influence drug dispersion and absorption to affect the pharmacokinetic profile and efficacy of a particular drug.

The therapeutic effect may be diminished, or toxicity enhanced when medications are administered through EADs in the critically ill. The bedside clinician must be aware of factors impacting the bioavailability of enterally administered medications and be cognizant that the effect will differ by medication.