Medication Administration Through Feeding Tubes

If a patient receiving EN is alert and can swallow oral medications, then, medications should be given by mouth. However, many patients are not able to receive medications by this route, and the feeding tube may be considered as a route of delivery. Although used widely, the effects of medication administration through feeding tubes on the delivery of both the drug and the EN formula nutrients have been inadequately studied, and important questions remain unanswered.45

Compatibility of medication with an EN formula and, conversely, an EN formula with administered medication is of concern when administering medications through feeding tubes. An important technical complication of EN is tube occlusion, related most commonly to medication administration. Not only must compatibility of the medication and the EN formula be considered, but interactions between these components and the feeding tube itself must be considered. Since either medication or EN formula or some combination thereof can physically stick to the tube itself, strict protocols for flushing the tube before, between, and after administration of medications are important.5 The best fluid for flushing feeding tubes is warm water. Carbonated beverages and fruit juices are no longer recommended and should be avoided because sugar in these products may stick to the surface of the feeding tube. Between 10 and 30 mL of water should be used as a flush before and after any medication administration through a feeding tube. Medications should be administered one at a time sequentially rather than being mixed together for simultaneous administration down the tube; about 5 mL of water should be used as a flush between each medication. This should help prevent interactions between drugs within the feeding tube itself that could lead to tube occlusion.

Different dosage forms present unique challenges for administration through feeding tubes. Certain solid dosage forms should not be crushed because crushing would significantly alter release characteristics.46 For example, controlled-release, extended-release, and sustained-release preparations should not be crushed; crushing allows a quicker release of more drug initially than the original dosage form was designed to deliver. Sublingual dosage forms should not be crushed. Enteric-coated dosage forms generally are designed to protect acid-labile medications from stomach acid; when these dosage forms reach the small bowel with its higher pH, the drug then is released into an environment in which it is more stable. Alternatively, enteric-coated dosage forms protect the stomach from medications that could cause irritation. Thus, crushing of the enteric coating for delivery down a gastric feeding tube defeats the purpose of the dosage form and could lead to decreased efficacy or increased adverse events.

Medications available commercially as compressed tablets can be crushed for administration through feeding tubes. After such a tablet is crushed into a fine powder, it should be mixed with 10 to 30 mL of fluid (usually warm water) for administration. A powdered dosage form inside a hard-gelatin capsule similarly can be poured out and mixed with water for administration through feeding tubes. Soft-gelatin capsules can be dissolved in warm water for administration. Some enteric-coated and delayed-release microencapsulated products can be opened, and the individually-coated particles can be administered through the tube without crushing if the tube has a large enough diameter.

If a liquid dosage form of a medication exists, it would seem rational to use this dosage form for administration through a feeding tube. Although this may decrease the potential for tube clogging, it may in some instances decrease tolerability of medication administration. As mentioned above, sorbitol is an excipient found in many liquid medications in amounts sufficient to cause diarrhea. If diarrhea secondary to sorbitol in a liquid medication is suspected, contact with the manufacturer to ascertain sorbitol content may be necessary.

Another potential problem with administration of liquid medications through feeding tubes is high osmolality of some of these products. Dilution of hypertonic medications with 30 to 60 mL of water (depending on osmolality of the medication and dosage volume of the undiluted medication) or administration of smaller dosages more frequently may help prevent diarrhea. Although administration of IV medications through feeding tubes sometimes may be entertained, these dosage forms frequently are hypertonic and contain excipients that can be problematic when given via the GI tract.

It is generally not recommended to mix medications directly into the EN formula because of concerns that physical incompatibilities between the medications and the formula might lead to tube occlusion. There is some evidence that polymeric formulas are more likely to demonstrate physical incompatibility with medications compared with monomeric formulas, although most of the work in this area has used casein or caseinate-based formulas, and other proteins may act differently.45 Limited data currently available indicate that acidic syrups and elixirs may be most harmful, causing physical incompatibility when admixed with EN formulas. This incompatibility may be due to changes in the protein structure after exposure to acid or alcohol.45

It would seem logical that medications considered being absorbed to a greater extent in the fasted state either should be given between feedings on an intermittent feeding schedule or the feedings should be held before and after medication administration. However, results of one provocative study with the antihypertensive medication hydralazine indicated that continuous feeding into the stomach resulted in a situation mimicking fasting in terms of rate of gastric emptying and drug absorption.45 This issue deserves further study.

The location of the tip of the feeding tube is important when considering medication administration down a feeding tube. This is particularly true if the medication acts locally in the GI tract itself. For example, sucralfate and antacids act locally in the stomach. Therefore, administration of these medications through a duodenal or jejunal tube is not logical. Likewise, for medications such as itraconazole that require acid for best absorption, administration directly into the duodenum or jejunum would be expected to result in suboptimal absorption. Absorption of drugs when administered directly into the small bowel, especially the jejunum, is a topic where more research would be useful.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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