Medication Administration Through Enteral Feeding Tubes

Nancy Toedter Williams, Pharm.D., BCPS, BCNSP


Am J Health Syst Pharm. 2008;65(24):2347-2357. 

In This Article

Obstructed Feeding Tubes

Small-bore enteral feeding tubes may become clogged in up to 35% of patients.[62] Various factors may contribute to tube occlusions and include enteral formulations (high viscosity or intact protein products), feeding tube characteristics (silicone tubes clog more frequently than polyurethane tubes), insufficient flushing, and incorrect medication administration.[1,63] Tube blockage may result in increased nursing time, interrupted nutrition and medication delivery, patient discomfort and trauma (if the tube requires removal), and higher costs.[13]

Preventing tube occlusions is preferable. During continuous enteral feedings, tubes should be flushed with 30 mL of water every four hours. For patients who receive intermittent or bolus administration of EN, tubes should be irrigated with 30 mL of water after each feeding.[63] Practices vary among nurses and hospitals regarding the type of water used for irrigation—sterile water versus tap water.[64] In addition to routine water flushing, the prophylactic use of a pancreatic enzyme solution mixed with sodium bicarbonate and water may reduce tube occlusions with both intermittent and continuous enteral feedings.[65,66] The sodium bicarbonate is used to activate the pancreatic enzymes and to raise the pH of the solution.[63,67]

In order to prevent feeding tube occlusions and to declog occluded tubes, the following steps should be taken to prepare an alkalinized enzyme solution[63,66,67]:

  • Crush one pancrelipase tablet (lipase 8000 units, amylase 30,000 units, protease 30,000 units) to a fine powder, or measure one fourth of a teaspoon of pancrelipase powder,

  • Crush one nonenteric-coated sodium bicarbonate 324-mg tablet to a fine powder, or measure one eighth of a teaspoon of baking soda, and

  • Dissolve powder mixture in 5 mL of warm water. This results in an activated pancrelipase pH 7.9 solution.

Medications can also contribute to tube clogging when tablets are not adequately crushed, when bulk-forming agents are administered, when medications interact with enteral formulas, or when inadequate tube flushing occurs.[63] Clogging can be prevented by flushing feeding tubes with 15–30 mL of water before and after drug delivery in order to minimize drug–formula interactions. Multiple medications should be given separately, with water irrigation between each one. As previously discussed, liquid medications are preferred, especially elixirs or suspensions versus syrups, and medications should not be mixed with enteral formulas unless compatibility is verified.[27,63]

If the feeding tube becomes clogged, intervention should occur immediately. Warm water should be tried first. If unsuccessful, declogging agents like meat tenderizer, carbonated beverages, and cranberry juice have been used. However, these have not proven to be more effective than plain water in clearing the obstruction. In fact, acidic liquids, such as cranberry juice and colas, may even worsen the problem by precipitating protein in the enteral formulas.[1,11,13,67] On the other hand, the pancreatic enzyme–sodium bicarbonate solution has been successful in restoring tube patency.[62,67] The Clog Zapper (Corpak Medsystems, Wheeling, IL) is a commercial device that has also shown efficacy in clearing occlusions. The system includes a syringe filled with an enzyme powder that is reconstituted with water and then instilled into the clogged tube through a catheter and allowed to dwell for 30–60 minutes before flushing with water.[63,68]


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