Medication Administration via Enteral Feeding Tubes

PARENTERAL NUTRITION (PN) - ADULT

CENTRAL 3-in-1 Dextrose _____ g

III. Medication Administration via Enteral Feeding Tubes

A. Medication dosage forms that can be administered via enteral tubes.

Medications that can be given via enteral tubes include immediate- release oral tablets, hard gelatin capsules, soft gelatin capsules, and liquid formulations. All medications should be mixed with appropriate diluents and administered separately; the feeding tube should be flushed with water before and after each medication is administered to minimize incompatibilities and prevent occlusion.

1. Immediate-release oral medications. Most simple, compressed tablets, including film- and sugar-coated and hard gelatin cap-

S E C T I O N I Fundamentals of Nutrition Support Practice and Management

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Drug HN Plus HN 1 cal HN Vivonex Comments

Acetaminophen/Codeine Elixir C C C

Acetaminophen Elixir C C C C C C

Actifed Syrup C C C C C

Amoxicillin Suspension C C C C

Amphogel I C C Thickens on contact

Bactrim Suspension C C C C C C

Benadryl Elixir C C C C C C

Bentyl Liquid I C Thickens on contact

Benylin DM C C C C C

Cephalexin Suspension C C C C C C

Cephulac C C C C C

Cibalith-S I I I I C Clumping

Compazine Elixir C C

Dexamethasone Elixir C C C C C C

Dimetane Elixir I I I I I C Gelatinous formation

Dimetapp Elixir I I I I I C Enteral product breaks down

Docusate Liquid C C C C C C

Donnatal Elixir C C C C C C

Doxepin Concentrate C C C C C C

EES Granules C C C C C

Feosol Elixir I I I I I C Complete gel formation

Fleet Phospho-Soda I I I C Instant clumping

Gantrisin Suspension C C C C C C

Gevrabon Liquid I C

Griseofulvin Suspension C C

Guaifenesin Liquid I I I I I C Flocculate precipitate

Haldol Drops C C C C C C

Imodium Liquid C C C

KCl Oral Liquid I I I I I Interphase incompatibility

Klorvess Granules C C C C

Lanoxin Elixir C C C C C C

Lasix Liquid C C C C C

Mandelamine Granules C C C C C

Mandelamine Suspension I I I I Gelatinous tacky formation

MCT Oil I I Adhesive gelatinous mass formation

Mellaril Concentrate C C

Mellaril Solution I I I I C Granular formation

Mestinon Suspension C C C C C

Milk of Magnesia C

Morphine Liquid C C C

Mylanta C C C

Mylanta II I I Thickening on contact

Navane Concentrate C C C C C C

Neo-Calglucon Syrup I I I I I C Adhesive gelatinous mass

Nitrofurantoin Suspension C C C C C C

Organidin Elixir C C C C C

Paregoric Elixir I I I C Instant clumping

Periactin C C C

Phenergan Syrup C C C C C

TABLE 9-1. Physical Compatibilities With Enteral Feeding Products

(Continued)

S E C T I O N I Fundamentals of Nutrition Support Practice and Management

sules filled with a fine powder, are amenable to administration via a feeding tube.

a) Tablets must be crushed to a fine powder (eg, with a mortar and pestle) and mixed with water before administration. The finer the powder the better, both to enhance absorption and reduce the risk of tube occlusion.

b) Hard gelatin capsules filled with a fine powder should be opened and mixed thoroughly with water before administration. Soft gelatin capsules can be emptied by creating a pin- hole in one end of the capsule and squeezing out the contents.

The contents can then be mixed with water. Precise dosing may not be possible, as it is difficult to remove all the capsule’s contents.

2. Liquid medications^20–22are the preferred alternative for administration via an enteral feeding tube because of better absorption and decreased potential for enteral tube occlusions. However, liquid medications are not without potential for producing adverse effects.

a) Liquid medications may cause physiologic incompatibilities (eg, diarrhea, elevated gastric residuals, distended abdomen, cramping).

b) These responses may not be attributed initially to the enteral feeding formulation and may be misdiagnosed as a tube- feeding intolerance.

c) The “intolerance” may in fact be attributable to the liquid medication preparation, as these medications often have a high osmolality or contain large amounts of sorbitol.^23–26

d) Hyperosmolar liquid medications may cause diarrhea, cramping, and increased gastric residuals. The osmolality of GI tract secretions is approximately 300 mOsm/kg. Liquid medica-

tions exceeding 300 mOsm/kg require GI dilution to approach the isotonic state to aid absorption; if the amount of fluid that moves into the GI tract exceeds the absorptive capacity of the intestinal tract, diarrhea will result.

e) The stomach may be more tolerant of hyperosmolar medications than the small intestine because of the stomach’s inherent ability to dilute hypertonic solutions with gastric juice before emptying the gastric contents into the duodenum.

f) Administration of undiluted hyperosmolar liquid medications directly into the duodenum or jejunum should be approached cautiously, as it causes a significant influx of water and elec- trolytes into the GI tract, which could contribute to bloating, nausea, cramping, diarrhea, and electrolyte imbalances.

g) Complications can be avoided by diluting hypertonic liquid medications with an appropriate amount of water. The site of medication delivery and the tonicity of the medication influ- ence the amount of water required. More diluent may be needed to dilute medications administered into the small intestine than into the stomach.

h) Coordinate the patient’s need for additional water with amounts of water needed to dilute hypertonic medications.

i) Osmolalities of liquid medications can reach as high as 9000 mOsm/kg of water. Check with the manufacturer or read the package insert for more information.^23,24

j) Medications that contain sorbitol often cause a physiologic incompatibility (eg, diarrhea, bloating, cramping). Doses as low as 10 g have been known to cause mild GI distress, with 20 g or more causing more severe symptoms.²⁶Children may be more susceptible to the effects of sorbitol than adults.

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Drug HN Plus HN 1 cal HN Vivonex Comments

C, compatible; I, incompatible References

Lutomski DM, Gora ML, Wright SM, Martin JE. Sorbitol content of selected oral liquids. Ann Pharmacother.1993;27:269–274.

Miller SJ, Oliver AD. Sorbitol content of selected sugar-free liquid medications. Hosp Pharm.1993;28:741–744, 755.

Niemiec PW, Vanderveen TW, Morrison JI, Hohenwarter MW. Gastrointestinal disorders caused by medications and electrolyte solution osmolality during enteral nutrition. J Par- enter Enteral Nutr.1983;7:387–389.

TABLE 9-1. Physical Compatibilities With Enteral Feeding Products (Continued)

Phenobarbital Elixir C C C C C C

Reglan Syrup C C

Riopan I C Thickening on contact

Simethicone Drops C C C C C C

Slo-Phyllin Syrup C C C C C

SSKI Liquid C C C C C

Sudafed Syrup C I I I I C Viscous gelatinous formation

Sumycin Syrup C C C C

Tagamet Elixir C I I C Thickening on contact

Terpin Hydrate Elixir C C C C C

Theolair Liquid C C C C

Theragran Liquid C C C C

Thorazine Concentrate I I I I C Granulation and particle formation

Triaminic Syrup I C C C C C

Zinc Sulfate I

S E C T I O N I Fundamentals of Nutrition Support Practice and Management

(1) Sorbitol is considered an inert ingredient that is added to enhance palatability and improve stability. Sorbitol may be present in all liquid medications except tinctures and emulsions. None of the reconstituted antibiotic preparations are known to contain sorbitol.²⁷

(2) The sorbitol content of a liquid medication may vary among manufacturers. Manufacturers do not list the sorbitol content on the label. The best source for determin- ing whether sorbitol is present is the package insert, but the manufacturer must be contacted to obtain the actual sorbitol content.

(3) The total daily dose of sorbitol provided by all liquid medication preparations administered must be considered.

(4) Common offending agents are acetaminophen elixir, theophylline solutions, valproate, and guaifenesin syrup.

These medications contain large quantities of sorbitol, and numerous doses may be given in a 24-hour period.

Any product may have a high concentration of sorbitol, but if the product dose in milliliters is small, the actual dose of sorbitol may also be quite small.

(5) Options for avoiding problems with sorbitol include changing to another manufacturer’s product, using therapeutically equivalent products that have less or no sorbitol, changing the route of administration, and using tablets or capsules that do not exhibit pharmaceutical incompatibility.

3. Suspensions

a) Suspensions present few incompatibility concerns.

b) Suspensions do not contain sorbitol.

c) Suspensions may be hyperosmolar; adding water to the dose will reduce tonicity.

d) Antibiotics are often available as suspensions. The diarrhea that may occur is a direct side effect of the antibiotic and is not related to the suspension form. Recolonization of the GI tract may be useful in these cases.

4. Granular-type medications

a) Psyllium hydrophilic mucilloid and cholestyramine resin may be added to a patient’s regimen to control diarrhea. Cholestyra- mine resin may also be added as a hypercholesterolemia agent.

b) These medications require dilution with water before administration. The granules rapidly absorb water and expand to form a gelatinous mixture that may occlude the enteral tube;

small-bore feeding tubes are more problematic than larger gastric tubes.

c) Metamucil may be administered by mixing 4 g with 80 mL of water and completing the dose administration within 5 minutes or less.²⁸The quick administration minimizes expansion of the granules and decreases the risk of tube occlusion.

d) A therapeutically equivalent medication should be considered if the patient has a small-bore feeding tube.

B. Medication dosage forms notrecommended for administration via tube

1. Enteric coated medications^20,21

a) Crushing these medications may induce a pharmaceutical incompatibility. A therapeutic equivalent or alternative administration route should be considered.

b) It is important to understand the purpose of the enteric coating and the location of the tip of the feeding tube.

(1) Enteric coating may protect the stomach lining. Certain formulations of aspirin are coated to decrease the gastric irritation often associated with its use. Administering a

crushed enteric-coated aspirin may produce some GI upset or irritation associated with aspirin, but the overall efficacy of the medication will most likely be unaltered.

(2) Enteric coating protects a number of medications (eg, erythromycin base, erythromycin stearate, pancrelipase) from destruction in the acidic environment of the stomach prior to absorption in the small intestine. Upon entering the alkaline environment of the duodenum, the enteric coating will dissolve and release the medication for absorption.

These medications require an intact enteric coating to pre- serve the integrity of the active drug during its passage through the stomach to ensure bioavailability.²⁹

(3) If a medication has an enteric coating solely for the purpose of preventing destruction from acidic acid, administration via a feeding tube beyond the pylorus is acceptable.

Check with a pharmacist to verify the purpose of the enteric coating.

2. Sublingual or buccal medications²⁰

a) These medications are placed under the tongue or in the cheek pouch and absorbed into the systemic circulation.

b) Administration via feeding tube is not recommended.

3. Sustained-release (SR) tablets or SR capsules.^20,21Crushing these medications is not recommended, as significant pharmaceutical incompatibilities or toxicities could occur.

a) Administering crushed SR tablets or capsules delivers a bolus of drug that was intended to be delivered over 6 to 24 hours.

The bolus causes high peaks with a potential for toxicity followed by low troughs and inadequate coverage.

b) Emptying capsules with extended-release beads into feeding tubes is not recommended because it increases the potential for tube occlusions.

c) Dissolving the beads in water or NaCl 0.9% solution is not recommended because it will adversely affect the integrity of the beads’ outer coating. This can affect the integrity of the medication and compromise the time-release properties.

d) Alternative therapeutic equivalents must be considered.

(1) Use a liquid therapeutic equivalent or a crushable immediate-release medication, or choose an alternative delivery route (eg, parenteral, rectal).

(2) If a therapeutically equivalent immediate-release medication is available as a tablet or liquid, it will require more frequent administration, usually at the same total daily dose as the SR form.

(3) Monitor for appropriate clinical response and, whenever warranted, adequate blood concentrations.

4. A comprehensive list of oral solid dosage products that should not be crushed is available.²⁰

5. Syrups^29–31

a) A physical incompatibility may occur when syrups are mixed with enteral formulations. Syrups with a pH of ≤4 can denature the protein in the enteral formulation, leading to an increase in viscosity that may contribute to feeding tube occlusions.

b) It is important to be aware of the protein source of the enteral formula. Syrup preparations administered with whole-protein formulations have been shown to cause physical incompatibilities; those with free amino acids or hydrolyzed formulations are not as affected by concurrent administration of syrup.

c) Physical incompatibilities (clumping, etc) cannot be avoided by diluting the syrup or the enteral formulation. Not all syrup products have an acidic pH ≤4. If there is suspicion that the product has a low pH, the pH may be tested with pH paper or

S E C T I O N I Fundamentals of Nutrition Support Practice and Management

a small amount of the syrup may be mixed with a sample amount of the enteral formulation to observe any affect on the formulation stability.

d) Alternatively, a compatible therapeutically equivalent medication (ie, a tablet or capsule form that could be sufficiently pulverized and diluted in water) can be selected or an alternative route of administration can be used. If the incompatible syrup must be administered via the feeding tube, the steps below should be followed:

(1) Stop the tube feeding.

(2) Flush the feeding tube with 30 mL of water to clear the tube of all formulation.

(3) Administer the syrup via the tube.

(4) Flush the tube with 30 to 60 mL of water to clear the tube of residual syrup and ensure tube patency.

(5) Resume the tube feeding.

C. Drug-nutrient interactions. Drug-nutrient interactions are situations in which the ultimate effect of a drug is altered by a nutrient or the ultimate effect of a nutrient is altered by a drug. Interactions could involve any of the previously mentioned types of incompatibilities.

1. Proton pump inhibitors available as capsules or tablets³² a) Capsules containing enteric-coated beads

(1) Enteric coating preserves the integrity of the medication until it reaches the alkaline pH of the duodenum, where the coating dissolves and absorption begins.

(2) Dissolving the beads in water removes the protective enteric coating, exposing the medication inside to a basic environment. In this basic environment, the active medication begins to degrade, thereby decreasing its overall effectiveness. Mixing with water also causes the beads to clump as the enteric coating dissolves. Clumping con- tributes to occlusion of enteral feeding tubes.

(3) Two alternative methods of delivery have published support.

(a) The contents of the capsule (omeprazole, lansoprazole, esomeprazole) may be mixed in an acidic fruit juice such as orange juice or apple juice. The enteric coating will remain intact until the beads reach the basic environment of the duodenum. One concern with this approach is that the intact beads may occlude small- bore feeding tubes. Not all of the dose is administered to the patient, as the beads can collect and remain lodged in the syringe hub.^32,33

(b) The beads can be dissolved in sodium bicarbonate 8.4% solution, creating a simplified suspension. Sta- bility is maintained at this high pH.³⁴

(c) Extemporaneous simplified suspensions of omeprazole and lansoprazole can be prepared. These formulations have proven to be effective in maintaining adequate buffering of stomach contents in the critically ill popu- lation.^35,36One study involving healthy individuals administered esomeprazole via a feeding tube immedi- ately after the drug was mixed with water demonstrated good results.³⁷

(d) The commercially available lansoprazole packets should not be administered via a feeding tube. The product contains particles or gums that will occlude a feeding tube.³⁸

(e) Simplified suspensions of proton pump inhibitor should be administered via feeding tubes to avoid tube occlusion.

(f ) An orally disintegrating form of lansoprazole is available. This dosage form circumvents the feeding tube route, as the pellets dissolve in the patient’s mouth and do not require swallowing.

(g) A powder formulation of omeprazole is commercially available and can be reconstituted for administration via enteral feeding tubes.

b) Enteric-coated tablets

(1) Crushing enteric-coated tablets has the same effect as crushing the enteric-coated beads in capsules.

(2) A pantoprazole extemporaneous solution can be prepared using sodium bicarbonate 4.2% solution.^39,40

c) Alternative options. Use an H2antagonist when possible.

(1) H2antagonists are available in liquid form and in easily dissolved tablets and capsules.

(2) Use parenteral proton pump inhibitor or H2antagonists only when the GI tract cannot be used.

2. Phenytoin. Impaired absorption of phenytoin is a pharmacoki- netic incompatibility^41–44that is well documented in the literature.

a) There appears to be impairment in absorption, but there is debate about where and how the interaction occurs. Possible reasons for impaired absorption include the following:

(1) The protein source of the enteral formulation may contribute to the interaction. Calcium caseinate protein sources may impair absorption more than sodium caseinates.

(2) The phenytoin suspension may bind to the enteral feeding tube.

(3) The phenytoin suspension has poor solubility and may contribute to poor absorption.

(4) There may be decreased gastric emptying, with subsequent destruction of phenytoin by gastric acid.

(5) Drug administration via a tube placed in the distal jejunum reduces transit time and time for drug absorption.

(6) Patients have decreased GI transit time (ie, the drug spends less time in the GI tract).

b) Patients receiving enteral formulations may need much higher phenytoin doses than usual to maintain therapeutic blood levels.

c) Seizures are a potential consequence of inadequate phenytoin blood levels.

d) Strategies to maintain therapeutic phenytoin levels and pro- vide adequate protection from seizures include the following:

(1) Hold the tube feeding 2 hours before and 2 hours after administering the phenytoin dose. Adjust the tube-feeding schedule to accommodate the total 24-hour requirement.

(2) Dilute the phenytoin with water (30 –60 mL) before administration. The water may enhance dissolution and improve absorption.

(3) Monitor blood levels more frequently when changing from an established therapeutic parenteral dose via vein to the suspension form administered via the feeding tube.

(4) Consider administering the parenteral form of phenytoin via enteral tube if problems persist in maintaining therapeutic levels. Supporting evidence at this time is limited to a single-dose trial in healthy subjects, which is not adequate to establish this route as a reliable alternative. The parenteral form is hyperosmolar and must be diluted before administration.⁴⁵

(5) Phenytoin toxicity can occur as the patient transitions from tube feeding to oral feedings, because of the removal of the

S E C T I O N I Fundamentals of Nutrition Support Practice and Management

offending interaction. Monitor the phenytoin levels closely until stable.

(6) Consider the use of IV phenytoin or fosphenytoin in difficult situations.

3. Warfarin. A decreased therapeutic response to warfarin has been noted in patients receiving enteral tube feeding.^46–48

a) The altered response was initially thought to be related to the high vitamin K content of enteral formulations.

(1) The vitamin K content could antagonize warfarin activity.

(2) Subsequently, the vitamin K content was reduced in most enteral products.

(3) Warfarin resistance continues to be reported in the literature.

b) Warfarin is a highly protein-bound drug.

(1) It has a protein-binding level in serum of 97.4% to 99.9%.

(2) It may bind to the protein in the enteral formulation.

c) One letter to the editor indicated success in one patient when the warfarin was administered during the 6-hour break in the patient’s daily 18-hour cycle.⁴⁹

d) Warfarin drug-nutrient interactions are less consistent than phenytoin drug-nutrient interactions.

e) Monitor anticoagulant activity closely while the patient is on enteral tube feeding.

f) Evaluate warfarin dose, anticoagulant goals, and monitoring parameters closely as the patient transitions to an oral diet or begins a bolus, intermittent gravity tube-feeding regimen.

4. Quinolones

a) Significant controversy surrounds the use of quinolones administered simultaneously with enteral feedings. Efficacy is best measured by evaluating the area under the curve (AUC) data and comparing these data to the minimum inhibitory concentration (MIC) of the bacterial strain being treated.

b) The AUC measures the total amount of quinolone that is absorbed over time. The AUC/MIC ratio is the most important predictor of efficacy.⁵⁰

c) Concurrent administration of quinolones with medications that are high in aluminum, magnesium, iron, and calcium can impair absorption, resulting in a clinically significant decrease in absorption.⁵¹

d) High concentrations of the following cations in enteral feeding formulations may also impair quinolone absorption.

(1) Ofloxacin

(a) A single-dose trial with a crushed tablet administered with a bolus of Ensure (Ross Products) produced a 10% reduction in the AUC.⁵²

(b) This was not a significant reduction compared to taking on an empty stomach with water.

(2) Ciprofloxacin

(a) There have been mixed results depending on what patient groups were studied and how the medication was administered.

i) Single-dose trials in which the tablet was crushed and administered simultaneously with a bolus of enteral feedings demonstrated reduced absorption.^53–55

ii) Nonsurgical, critically ill patients receiving continuous enteral tube feeding and receiving multiple doses of ciprofloxacin have demonstrated adequate absorption.^56,57

(b) Adequate GI tract function must be established prior to changing ciprofloxacin from the parenteral route to

the enteral route.⁵⁸

i) It may not be advisable to change ciprofloxacin to the feeding tube route if pseudomonal respiratory tract infection is being treated. The feeding tube route should be acceptable for patients with urinary tract infections.

ii) For a more detailed discussion on this topic, refer to a review article by Nyffeler.⁵⁹

(3) Levofloxacin. No information is presently available.

(4) Gatifloxacin. A single-dose prospective two-way crossover trial in critically ill patients comparing AUC for the parenteral product to a single dose administered via a feeding tube with concurrent enteral feeding did not demonstrate a difference in overall bioavailability.⁶⁰

5. Atovaquone. A single-dose trial of atovaquone suspension administered to healthy patients within 1 hour of an enteral supplement produced levels of absorption similar to those taking it with a normal breakfast.⁶¹

6. Carbamazepine

a) Administration with concurrent tube feedings should not be a problem if an appropriate dilution-and-flush routine is used.

b) One trial demonstrated that administration of undiluted carbamazepine suspension via a polyvinyl feeding tube resulted in decreased absorption. Diluting the suspension prior to administration produced more normal delivery.⁶²

c) An insignificant reduction in overall absorption was demonstrated in a small trial of healthy patients. This was a crossover trial that demonstrated 90% bioavailability of carbamazepine suspension when taken after fasting or with continuous enteral feedings.⁶³

d) Serum concentrations should be monitored closely after patients are started on carbamazepine and enteral feedings. A consistent method of administration should be used.

e) A report describes the use of an extended-release version of carbamazepine (Carbatrol) via feeding tubes in pediatric patients.⁶⁴This trial administered the contents of the capsule via feeding tubes. No mention was made of carbamazepine levels or side effects, but the patient’s family noted frequent occlusion of the feeding tube. Administering capsule contents via feeding tubes always presents the potential for occluding the feeding tube and is probably best avoided.

7. Carbidopa/levodopa

a) No trials have evaluated absorption of carbidopa/levodopa with concurrent enteral feedings.

b) Extrapolations have been made from the data showing a decreased effect when the medication was taken with a high-protein meal. The amino acids in the high-protein meal inhibited transport across the blood-brain barrier via a com- petitive uptake mechanism.

c) If patients are receiving intermittent feedings, doses should be administered during off-time. Another option is to explore alternative medications for Parkinson’s that do not exhibit this interaction.

8. Clarithromycin. Administration of suspension, which contains granules, may result in occluded feeding tubes.

9. Hydralazine. Absorption in continuous enteral feedings is compa- rable to that of fasted patients.⁶⁵

10. Fluconazole

a) A number of trials in patients in intensive care unit support the administration of fluconazole via a feeding tube in conjunction with continuous enteral feedings.^66,67

Dalam dokumen The A.S.P.E.N. Nutrition Support Practice Manual, 2nd Edition (Halaman 140-146)