Administering medicines via enteral feeding tubes

  • Administering medication via an enteral feeding tube requires thought and exercise of clinical judgement
  • Most medicines are not licensed for administration via enteral feeding tubes and professionals responsible for prescribing, supplying and administering them accept liability for their use

Initial Considerations

  • Is medication essential?
  • Can an alternative route be used? eg, topical, sublingual, rectal, IV
  • Is there a more suitable formulation within the same therapeutic class?
  • Is the oral route available for medicines administration?
  • What is the size and site of feeding tube? eg. NG, NJ, PEG

Medicine Formulations

Formulation Advantages Disadvantages
Liquid solution Easy to measure
Accurate dosing
Ready to use
Excipients can cause diarrhoea eg. sorbitol
Multiple bottles may be required
Hyperosmolar medicines can have GI side effects
Bioavailability can differ between liquid and tablet formulations eg. digoxin
Liquid suspension (insoluble drug in a suspending agent) Easy to measure
Ready to use
Large granule size can block tubes
Unlicensed ‘specials’ can be expensive
Need adequate mixing to ensure accurate dosing
Soluble tablets (dissolve in water) Drug is in solution
Accurate dosing
Generally inexpensive
Convenient
Some drugs can take time to dissolve
Dispersible tablets (disintegrate in water) Accurate dosing
Generally inexpensive
Convenient
Drug particles may block tube
Effervescent tablets (disintegrate and fizz in water) Accurate dosing
Convenient
Sodium content can be high
May require large volume of water
Some drugs can take time to disperse
Opening capsules Convenient
Relatively inexpensive
Contents may not disperse in water
Occupational exposure eg. antibiotics
Can be difficult to open

In general the preferred formulations are liquid solutions and soluble tablets.

Crushing tablets and opening capsules should be considered as a last resort due to inaccuracies in dosing, length of time for preparation and risk of occupational exposure.

If unsure, a pharmacist or local medicines information department should be contacted.

Medicines that should NEVER be crushed include:

  • Modified/extended release tablets
  • Enteric coated tablets
  • Cytotoxics
  • Hormones

Please note that most orodispersible tablets eg. lansoprazole fastabs, loperamide melts, are NOT suitable for sublingual administration.

Nasojejunal tubes

NJ tubes have greater potential to block due to longer length and smaller lumen. Some medicines are unsuitable for NJ administration as this bypasses gastric and duodenal absorption. Hyperosmolar medicines can cause GI side effects as the diluting effect of the stomach is bypassed. Advice from a pharmacist should always be taken before medication is administered via an NJ tube.

Drug and feed interactions

Some medicines interact with enteral feeds causing a reduction in drug or feed absorption or a tube blockage. This can be avoided by using once daily dosing if possible, changing to an alternative medicine and/or administering medicines during a break in feeding. A pharmacist should always be consulted before administering medicines and feed via an enteral feeding tube. Some examples of drug interactions include:

Medicine Effect of interaction Solutions
Phenytoin Reduced absorption
Sub-therapeutic levels
Give intravenously
Stop feed 2hrs before administration
Give once daily if possible
Monitor plasma levels
Warfarin Reduced absorption and effect dependent on vit K content of feed Monitor INR and adjust dose
Give s/c LMWH
Flucloxacillin Reduced absorption as best absorbed on an empty stomach Give intravenously
Change to alternative antibiotic
Sucralfate Reduced effect as binds to feed
GI obstruction
Stop feed 1hr before administration and restart 1hr after

Practical considerations

  • Flush tube with 30ml water at beginning and end of medicines administration (unless fluid restricted)
  • Flush tube with 10ml water between each individual medicine
  • Use largest practical enteral syringe to avoid tube damage
  • Do not mix medicines for enteral tube administration
  • Prescribe for appropriate route on drug chart eg. NG, NJ, PEG and not PO
References

NHS Greater Glasgow + Clyde Nutrition Resource Manual; Section 5, part 3.
British National Formulary 72. September 2016.
NMC, Standards for medicines management, London: Nursing and Midwifery Council 2009.
White R & Bradnam V. Handbook of Drug Administration Via Enteral Feeding Tubes – 3rd Ed. Pharmaceutical press. 2015.
Williams N. Medication administration through enteral feeding tubes. Am J Health Syst Pharm. 2008;65:2347-2357.

Further information available here


Thanks are due to many healthcare professionals who provided copy for this area of the BAPEN website. Among them from PENG are...

  • Annelie Shaw
  • Katrina Wood
  • Caroline Goodger
  • Kallum Rhule
  • Sean White

And from BPNG are...

  • Graeme Doherty
  • Rebecca White

With thanks also to the PENG committee of 2016 who reviewed content.

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