Can oral medications be given to patients with small bowel obstruction (SBO) and a nasogastric (NG) tube?

Medication Administration in Small Bowel Obstruction with NG Tube

In patients with small bowel obstruction (SBO), oral medications should generally be avoided, and medications should be administered through alternative routes when an NG tube is in place for decompression.

Understanding the Rationale

The administration of oral medications in SBO presents several significant concerns:

1. Mechanical obstruction: SBO prevents normal transit of intestinal contents, including medications, which can:

   • Accumulate proximal to the obstruction
   • Fail to reach their intended absorption sites
   • Potentially worsen the obstruction

2. NG tube function: When an NG tube is placed for decompression in SBO, its primary purpose is to:

   • Remove gastric contents
   • Reduce pressure proximal to the obstruction
   • Prevent vomiting and aspiration

Medication Administration Guidelines in SBO

When NG Tube is Present for Decompression

1. Preferred medication routes:

   • Intravenous (first choice)
   • Subcutaneous
   • Intramuscular
   • Transdermal

2. Medications through NG tube:

   • Generally contraindicated when the NG tube is for decompression in SBO 1
   • Any medication given through the NG tube would likely be immediately suctioned out

Special Considerations for Drug Formulations

If alternative routes are not available and medication must be given through an enteral tube:

• Avoid sustained/delayed-release medications as they require intact GI transit 1
• Liquid formulations are preferred over crushed tablets
• Each drug should be administered individually with 30 mL water flushes before, between, and after medications 1

Medication Administration After Resolution of SBO

Once bowel function returns and the NG tube is no longer used for decompression:

1. Transition to oral medications should occur only after:

   • Resolution of obstruction is confirmed
   • Return of bowel sounds
   • Passage of flatus or stool
   • Tolerance of oral intake

2. When using NG/NJ tubes for feeding (not decompression):

   • Medications may be administered through the tube following proper protocols
   • Flush with 30 mL water before and after medication administration 1

Potential Pitfalls and Caveats

• Drug absorption may be unpredictable in patients with altered GI anatomy or function 2
• Bioequivalence between oral and nasogastric administration cannot be assumed for all medications 2
• Tube obstruction risk increases with improper medication administration techniques
• Drug-enteral formula interactions may occur if medications are given with feeds 1

Evidence of Alternative Approaches

Some limited research suggests that specific oral medications might be beneficial in partial adhesive SBO:

• A study found that a combination of oral laxative, digestant, and defoaming agent decreased the need for surgical intervention in partial adhesive SBO 3
• However, this approach is not standard practice and requires further validation before widespread implementation

Conclusion

The management of medications in patients with SBO requires careful consideration of the pathophysiology of obstruction and the purpose of NG tube placement. When an NG tube is in place for decompression, parenteral routes of medication administration should be prioritized to ensure effective treatment and avoid complications.