Key Medication Considerations for Patients with Enteral Feeding Tubes

Understanding Feeding Tube Placement and Its Impact on Medication Absorption

There are numerous gastric and enteral feeding tube types, each designed for specific clinical situations. It's essential to be aware of the type and placement of the tube in use, especially the termination point. This knowledge is particularly relevant for clinical pharmacists, as the site where the tube ends can influence drug absorption. While the stomach is a common absorption site for many medications, some require gastric acid for absorption. When a tube bypasses the stomach and terminates in the duodenum or jejunum, the absorption profile of these medications may be reduced, potentially affecting their bioavailability.

Formulation Choice:

Before considering crushing a medication, the texture, form, and crushability of a medication must be determined. Not every medication can or should be crushed. Altering a medicine by crushing or dispersing it may change its stability and absorption, leading to reduced efficacy, increased toxicity, or an unpleasant taste/texture1. For instance, controlled-release formulations like Oxycontin, delayed-release ones such as sulfasalazine EN tablets, cytotoxic medications, and buccal and sublingual tablets like ondansetron ODT should not be crushed due to risks like dose dumping or toxicity.

Enteral Tube Considerations:

Tube Diameter: Narrower tubes (8-12 French diameter) are more blockage-prone. In contrast, wide-bore tubes (14 French diameter or larger) are stiffer but less likely to get blocked.

Line Adsorption: Some medications, such as Carbamazepine, might adsorb to the NGT, affecting their bioavailability. It's advised to dilute such medicines with an equal water volume to prevent adsorption. Therapeutic drug monitoring can be beneficial due to potential absorption barriers1.

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Medication Considerations for Patients with Enteral Feeding Tubes:

1.?????? Re-evaluate if the medication is still necessary. Non-critical medications may be able to be ceased upon discussion with the prescriber.

2.?????? Explore if the current oral medication has an alternate administration route (e.g., transdermal, parenteral, rectal, sublingual/buccal). Refer to the specific medicine monograph. E.g. isosorbide mononitrate tablets could be changed to glyceryl trinitrate patches.

3.?????? Consider switching to another medication with a more suitable administration route.

4.?????? If a change isn't feasible, see if the medication is available as a liquid or dispersible/soluble tablet. Dispersing a tablet is often better than crushing it. For example, while phenytoin capsules contain phenytoin sodium, the liquid form has phenytoin. A conversion calculation is essential when substituting capsules with liquid.

5.?????? Consider if the feeding regimen needs adjustments. Many medications interact with enteral feeds. This can have consequences such as decreased absorption, altered therapeutic effects and adverse effects or, on occasion, blockage of the enteral feeding tube. Medications may need to be given during a feeding break.

6.?????? Consult references on the crushing of medicines. In Australia, refer to the "Don't Rush to Crush" handbook for guidance on dispersing or crushing tablets or capsules. Choose the best option for your patient.

7.?????? Always flush the tube with water before and after administering each medicine1,2.

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Only disperse or crush medicines if:

1.?????? The monograph confirms its safety.

2.?????? The prescriber is informed and agrees.

3.?????? There are no safety concerns for the patient or administrator.

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Before Verifying (Pharmacists) or Administering (Nurses) Medicine via a Feeding Tube, Ensure You Know:

• The enteral feeding regimen.
• How food or feeds affect medicine absorption.
• The tube type.
• The tube end's location (for nasogastric tubes and orogastric tubes, it's the stomach).
• The medicine's absorption site.
• Any patient fluid restrictions. Administering medicines via enteral feeding tubes can be challenging if the patient can't tolerate the recommended fluid volume. Using less fluid can cause issues like cramping, diarrhoea, or tube blockage1.

For Nurses: Medication Administration Considerations via Enteral Tube:

• Medicines can be given between or after intermittent or bolus feeds. Avoid adding them directly to the enteral feed.
• If a medicine needs an empty stomach and is given once daily, administer during feed breaks.
• Pause feeds for at least 30 minutes before and after dosing for tubes terminating in the stomach. Those with slow gastric motility might need a longer break.
• For medicines affected by enteral nutrition, a feed break of up to 2 hours before and after might be necessary.
• If feed breaks are frequent or lengthy, consult a dietitian for nutritional guidance.
• If feeds can't be paused long enough, the medicine dose might need adjustment3,?.

Always discuss changes in medication dose, frequency, or form with the prescriber, and document the decision. Monitor the patient, especially if the formulation changes or if they regain their swallowing ability.

Using a medication in a way not specified in its Product Information, such as crushing it for oral or tube administration, may be considered off-label use. This increases the legal responsibility for the prescriber, pharmacist and the person administering the medication1.

Disclaimer: Please note that this is a general summary of medication considerations for patients with enteral feeding tubes. I am not affiliated with the Pharmacy Board of Australia, AHPRA, or the Australian Pharmacy Council. All content provided here is a result of my personal experience, accumulated knowledge and the references below.

References:

1.?????? Society of Hospital Pharmacists Australia. Don't Rush to Crush. 4th ed. [Australia]: Society of Hospital Pharmacists Australia; [2023].

2.?????? "How enteral feeding tubes affect medicines." SPS NHS. Published 8 March 2022. Last updated 7 April 2022. Available from: ??????????://??????.??????.??????.????/????????????????/??????-??????????????-??????????????-??????????-????????????-??????????????????/#:~:????????=??????%????????????????%????????????????????%??????????%??????????????????????%??????????????????%????????????????%????????????????,??????%????????????????????%????%??????.??.%??????????????????????????%????????????????????????%????%??????????.%????????????%??????????????. Accessed [01/11/2023].

3.?????? West Essex CCG. Medicines Optimisation in Patients with Dysphagia. [Internet]. [place unknown]: West Essex CCG; [date unknown] [cited 2023 10 30]. Available from: ??????????://????????????????????????.??????.????/????????-????????????/??????????????????-????????????????????????-??????-????????????????/????????????????-????????????????????-??????-??????????????????????-??????????????????????/????-??????????????????-??????-??????????/??????????????????/????????-??????????????????-??????????????????????-????????????????-??/????????

4. Wrexham Maelor Hospital, Pharmacy Department. Flowchart adapted from: [??????????://??????.??????????????????????????????????.??????/????????????????????????????????????????????????????????????.????????] - Copyright ? 2019 J Smyth, Betsi Cadwaladr University Local Health Board