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

Enternal Access Sites and Delivery Methods

Various enteral feeding tubes are available for delivering medications and nutrients to the patient. The tubes are typically classified by site of insertion (e.g., nasal, oral, percutaneous) and location of the distal tip of the feeding tube (e.g., stomach, duodenum, jejunum) (Figure 1). The choice of an enteral access route depends on several factors, including the patient's concurrent diseases or injuries, the presence or risk of impaired gastric motility or aspiration, and the anticipated duration of nutrition support. The stomach is traditionally used for delivery of EN because use of this site is generally more convenient, less costly, and less labor intensive than others. The stomach is also able to tolerate various medications and enteral formulas, including hypertonic preparations. However, small bowel access may be preferred in patients with pancreatitis, gastro-paresis, or severe gastroesophageal reflux disease, as well as in patients who have consistently high gastric residual volumes or who are at greater risk for aspiration. Jejunal feedings have not consistently been proven to reduce aspiration, and they may cause abdominal cramping and diarrhea.[6,7,8,9,10]

Figure 1.

Locations of various types of feeding tubes. Nasoduodenal, nasojejunal, and percutaneous endoscopic jejunostomy tubes extend (dotted line) to the small intestine instead of ending in the stomach. Adapted from reference 6. Illustration by Taina Litwak, CMI.

For patients who require short-term EN, nasoenteric feeding tubes are commonly used because they are easier to place and less costly than other enteral access routes. These feeding tubes may be inserted nasally, with the distal end of the tube in the stomach (nasogastric [NG]) or in the small intestine (nasoduodenal [ND] or nasojejunal [NJ]). A tube inserted through the mouth into the stomach (orogastric [OG]) is another option for short-term feeding, particularly when a tube cannot be placed nasally because of head injury or sinusitis. The OG route may also be reserved for premature or small infants who can only breathe through their nose.[6,7,8,10] For patients who require long-term EN (i.e., more than four to six weeks), percutaneous feeding tubes may be inserted in the stomach, duodenum, or jejunum via laparotomy, laparoscopy, endoscopy, or fluoroscopy. Percutaneous endoscopic gastrostomy (PEG) is the most popular technique used for obtaining long-term enteral access because it can be performed under conscious sedation in an endoscopy center or even at the bedside. Using this method can help reduce costs, avoid general anesthesia, and shorten the recovery period.[6,7,8]

Enteral feeding may be administered by various methods, including continuous, cyclic, bolus, and intermittent. The delivery method is determined by the tip location of the feeding tube (e.g., gastric, jejunal), the patient's clinical condition and tolerance to EN, and the overall convenience.[6] Continuous feedings are administered at a slow, continuous rate over a 24-hour period with sporadic interruptions for drug delivery or medical procedures. This is the preferred method when initiating EN in hospitalized patients, when infusing EN directly into the small bowel, and when patients are critically ill.[6] However, this method is also the most problematic for drug–nutrient interactions and frequently requires interrupting tube feedings when administering medications. Repeatedly interrupting continuous feedings for drug delivery is also challenging for health care workers because they have to stop and restart the feedings in a timely manner before and after medication administration. Additionally, the tube feeding rate may need to be increased to provide appropriate nutrition during the shortened infusion period.

Cyclic EN administration involves continuous feeding over a specified period (i.e., 8–20 hours per day). It is generally infused at night, thus allowing independence from the feeding equipment during the day and also encouraging oral intake in the daytime. Like continuous administration, this delivery method may be used when feeding into the stomach or small intestine.[6,11]

Bolus feedings closely mimic usual eating patterns and involve the infusion of EN over a short time period at specified intervals—usually four to six times per day. This rapid delivery method is commonly used when feeding into the stomach, and it is generally not well tolerated in patients with small bowel access; however, it offers the advantage of allowing medication administration to be separated from the feedings.[6,11]

Intermittent administration of EN uses a similar technique to that of bolus feeding, but it is used over a longer duration, which may help improve tolerance. This delivery method is also not recommended when feeding into the small bowel.[6,11]


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