Medicines Q&As
Q&A 320.3
How do the different types of enteral feeding tubes available affect
drug administration?
Prepared by UK Medicines Information (UKMi) pharmacists for NHS healthcare professionals
Before using this Q&A, read the disclaimer at www.ukmi.nhs.uk/activities/medicinesQAs/default.asp
Date prepared: 2nd January 2014
Background
Enteral feeding tubes present a number of problems with regard to drug administration. A knowledge
of the different types in use is essential when recommending options for drug administration through
an enteral feeding tube.
Answer
Enteral feeding is used to deliver nutrients to patients who have inadequate oral intake or in whom
oral feeding is to be avoided for a prolonged period, providing their gastrointestinal (GI) tract is
functioning.
Tubes may be broadly classified by their entry sites and where the tube terminates in the GI tract. The
material and diameter of the tubes and timing of feeds are also important considerations when
recommending drug administration techniques (1).
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. Smaller bore tubes are more
comfortable for the patient but present problems with regards to clogging by enteral feed solution or
medications (2). For medication administration, a tube with a diameter of at least 8Fr should be
suitable (3).
Material
Tubes may be made out of silicone, latex, polyvinylchloride (PVC), or polyurethane (PUR). As with
intravenous giving sets, drugs may adsorb onto the tube material itself, reducing bioavailability of the
drug. The 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 is
the same (2).
Sites of Tubes
Table 1 gives a summary of the different types of enteral feeding tubes (1,2,5). Nasal feeding tubes
are generally used for short term enteral feeding as they require less maintenance, whereas National
Institute for Health and Clinical Excellence (NICE) guidance recommends that if feeding is expected
to last more than 4 weeks, a percutaneous method is used. NICE also states that feeding tubes which
terminate in the stomach are preferred unless the patient has upper gastrointestinal dysfunction (4).
Table 1: Common types of enteric feeding tubes
Name
Nasogastric (NGT)
Entry Point
Nose
Exit Point
Stomach
Nasoduodenal (NDT)
NasoJejunul (NJT)
Nose
Nose
Duodenum
Jejunum
Usual Size
Fine bore: 6Fr-12Fr for feeding
Large bore: 12-16 Fr for
aspiration
Small bore
Fine bore 6-10 Fr
Available through NICE Evidence Search at www.evidence.nhs.uk
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Medicines Q&As
Percutaneous
Gastrostomy (PEG)
Percutaneous
jejunostomy (PEJ)
Percutaneous
Gastrojejunostomy
(PEGJ)
Orogastric (OG)
Abdomen
Stomach
Fine bore/ Large bore
Abdomen
Jejunum
Small bore
Abdominal wall
Jejunum via the
stomach
Small bore
Mouth
Stomach
Small/ Large bore
Patients with severe gastro-intestinal reflux disease, pancreatitis or gastroparesis are more likely to
have tubes which end in the small bowel (e.g. duodenum, jejunum or ileum) (1).
Feeds
Feeds may be administered continuously, intermittently, as a bolus, or in a cycle. 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 drug-nutrient interactions. Bolus feedings, which
most closely resemble normal feeding patterns, are used for gastric administration of feeds and can
allow medication administration to be spaced between feedings. Intermittent feeding involves longer
periods of drugs administration than bolus so medications can be carefully planned around feedings
(1).
Considerations for Medicines Administration via PEG tubes
There are a number of factors to consider when administering medicines through an enteral feeding
tube (1,2,3). These are set out in table 2.
Table 2: Factors to consider when administering medicines through an enteral feeding tube
Issue
Size of tube
Tube site
Tube Function
Feed timing
Drug Administration
Route
Drug formulation
Legal Implications
Notes
Narrow and long tubes are likely to become blocked by larger drug particles
or viscous solutions (2).
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 (1). Drugs such as ketoconazole, which require an
acidic environment to be absorbed optimally, may have a reduced
bioavailability (1). Conversely, increased bioavailability of some drugs such
as opioid analgesics, beta-blockers, and tricyclic antidepressants, may
occur due to reduced first-pass hepatic metabolism (1).
Tubes which are being used for aspiration or drainage should not be used
for drug administration purposes. This is particularly important for multilumen tubes as care must be taken to ensure drugs are administered into
the correct lumen.
Feeds may interact with drugs to reduce bioavailability.
Can the drug be administered by a different route? E.g. intravenous,
transdermal, buccal etc.
Is the drug essential?
For a list of injections which may be given orally, see Q&A number 175.
Modified release formulations should not be given via a feeding tube.
More viscous liquids e.g. syrups may clog tubes, as may larger drug
particles.
For most medications, administration through an enteral feeding tube is
outside product licences.
Available through NICE Evidence Search at www.evidence.nhs.uk
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Medicines Q&As
Summary


Not all enteral feeding tubes are the same. Common types include nasogastric, nasojejunal,
nasoduodenal, percutaneous gastrostomy, percutaneous jejunostomy and percutaneous
gastrojejunostomy.
Factors which may affect drug delivery include the size, placement, and function of the tube, as
well as drug factors such as formulation and alternative administration routes.
Limitations
This Medicines Q&A is intended to be a quick reference summary to different types of enteral feeding
tubes, in relation to medication issues. It does not detail individual drugs which may be administered
via enteral feeding tubes. For information on administration of individual drugs via an enteral feeding
tube, contact your local medicines information service, which you can find via the UKMi directory.
Quality Assurance
Prepared by
Hayley Johnson, Regional Drug & Therapeutics Centre, Newcastle upon Tyne
Date Prepared
2nd January 2014
Checked by
Monica Mason, Regional Drug & Therapeutics Centre, Newcastle upon Tyne
Date of check
2nd January 2014
Search strategy
Embase: *PERCUTANEOUS ENDOSCOPIC GASTROSTOMY/ OR *TUBE FEEDING/ *OR
ENTERIC FEEDING/
AND *DRUG ADMINISTRATION
Medline: GASTROSTOMY/ OR ENTERAL NUTRITION/
AND drug administration.ti.ab (freetext search)
In house resources
NICE website
References
1. Toedter Williams N. Medication administration through enteral feeding tubes. Am J Health Syst
Pharm 2008; 65: 2347-2357.
2. White R and Bradnam V. Handbook of Drug Administration via Enteral Feeding Tubes. (online).
London: Pharmaceutical Press; [Accessed via www.medicinescomplete.com on 02/01/2014] 4-8.
3. Mason P et al. Nutrition-Supporting Pharmacy Services. CPPE open learning programme. Outset
Publishing: 2007, 80-85
4. National Institute for Health and Clinical Excellence. Clinical Guideline 32. Nutrition Support in
Adults: oral nutrition support, enteral tube feeding and parenteral nutrition. 2006, page 30-31.
Accessed via http://www.nice.org.uk/nicemedia/live/10978/29979/29979.pdf
5. Stroud M, Duncan H and Nightingale J. Guidelines for enteral feeding in adult hospital patients.
Gut 2003; 52: vii1-vii12.
Available through NICE Evidence Search at www.evidence.nhs.uk
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