Enteral feeding

Tube feeding is the administration of nutrients in a liquid form via an enteral tube.

Enteral feeding

• healthcare professionals should consider enteral tube feeding in people who are malnourished or at risk of malnutrition as defined in National Institute for Health and Clinical Excellence NICE Guidance Nutrition support for adults (CG32), and have:
  • inadequate or unsafe oral intake, and
    
  • a functional, accessible gastrointestinal tract
    
    
• enteral nutrition is usually favored over parenteral nutrition for various reasons
  • some of its advantages are fewer infectious complications, reduced cost, earlier gut function, and reduced length of hospital stay (2)
  • in some clinical scenarios such as short bowel syndrome, bowel obstruction, and patients who may be at increased risk of morbidity and mortality, parenteral nutrition would be favored (2)

Factors affecting medicines administration

Enteral feeding tubes may be broadly classified by their entry sites and where the tube terminates in the GI tract.

Before giving a medicines via an enteral feeding tube there are certain factors to consider:

• Tube size
  • tube diameter
    • diameters are expressed using the 'French' unit. This measurement refers to the external diameter of the tube. One French unit represents 0.33mm
    • small bore tubes may be between 5-12 French and large bore tubes are those which measure more than 14 French
    • for medicine administration, a tube with a diameter of at least 8Fr should be suitable
    • narrow and long tubes are likely to become blocked by larger drug particles or viscous solutions
• Site of absorption
  • as with intravenous giving sets, drugs may adsorb onto the tube material itself, reducing bioavailability of the drug
  • material which a tube is made out of can also affect the size of the lumen
    • softer materials such as silicone and latex will require more material; so as a consequence the lumen size of tubes made of these materials will be smaller than those made of PVC or PUR, even if the French size (diameter) is the same
  • drugs such as ketoconazole, which require an acidic environment to be absorbed optimally, may have a reduced bioavailability
  • there may be increased bioavailability of some drugs such as opioid analgesics, beta-blockers, and tricyclic antidepressants
    • due to reduced first-pass hepatic metabolism
  • tubes which terminate in the jejunum cause a particular concern for drug administration as the tube may bypass the site of drug absorption and the drug will be in the GI tract for a reduced amount of time
    • drugs such as antacids, sucralfate, and bismuth are unlikely to work as they have a local effect in the stomach
      
      
• Tube Function
  • tubes which are being used for aspiration or drainage should not be used for drug administration purposes
    
    
• Feed timing
  • continual feeding will require interruptions for drug delivery but is the preferred method for jejunal tubes
  • cyclic administration involves continuous feeding for a particular period
    • if administration is overnight, this may help to reduce the problems associated with medicine-nutrient interaction
  • bolus feedings
    • most closely resemble normal feeding patterns
    • used for gastric administration of feeds and can allow medicine administration to be spaced between feedings
  • intermittent feeding
    • involves longer periods of medicines administration than bolus so medicines can be carefully planned around feedings

Modified release tablets should not be given via a feeding tube (1)

More viscous liquids e.g. syrups may clog tubes, as may larger drug particles (1)

For a list of injections which may be given enterally, see https://www.sps.nhs.uk/articles/what-injections-can-be-given-enterally/

Reference:

• NHS Specialist Pharmacy Service (March 2022). How enteral feeding tubes affect medicines
• Abu Hdaib N, Albsoul-Younes A, Wazaify M. Oral medications administration through enteral feeding tube: Clinical pharmacist-led educational intervention to improve knowledge of Intensive care units' nurses at Jordan University Hospital. Saudi Pharm J. 2021;29(2):134-142. doi:10.1016/j.jsps.2020.12.015