This chapter will review the pharmacotherapy for management of gastrointestinal (GI) fistulas, postoperative ileus, nausea, and vomiting and upper GI bleeding according to expert opinion.

GI fistulas


An abnormal connection between the GI track and the skin, another internal organ, or an internal cavity.


  • Postoperative fistulas (most common; 80%)

  • Spontaneous fistulas (Crohn disease and inflammatory bowel disease are the leading cause)

  • Trauma-induced fistulas


  • Fluid resuscitation and electrolyte management (see Chapter 21 )

  • Drainage

  • Nutrition (enteral vs. parenteral)

  • Octreotide

    • Mimics natural somatostatin found in the GI by inhibiting hormone secretion, exocrine secretory response, GI motor activity, and nutrient absorption and stimulation of water and electrolyte absorption.

    • Dose: 100 mcg subcutaneously three times daily

    • Discontinue if no response within 48 h

Postoperative ileus (POI)


A transient GI dysmotility following a surgery.


  • Increased sympathetic stimulation postoperatively

  • Damage to the vagal nerve during abdominal surgery

  • Inflammation of the GI tract after surgery

  • Drugs: anesthetics, opioids, anticholinergics

Pharmacologic management ( table 8.1 )

Table 8.1

Pharmacologic Management of POI

Data from Schwenk ES, Grant AE, Torjman MC, et al. The efficacy of peripheral opioid antagonists in opioid-induced constipation and postoperative ileus: a systematic review of the literature. Reg Anesth Pain Med . 2017;42:767–777.

Opioid-Sparing Analgesic Agents: NSAIDs
Ketorolac (Toradol)
15 mg, 30 mg injection
15–30 mg IV q6h PRN
Max: 5 days
Opioid sparing via analgesic and anti-inflammatory effects. Need to ensure adequate hydration prior to NSAID use. CrCl <30: avoid use
Ibuprofen (Caldolor)
800 mg injection
400–800 mg IV q6h PRN
Diclofenac (Dyloject)
37.5 mg injection
37.5 mg IV q6h PRN
Bisacodyl (Dulcolax)
10 mg suppository
10 mg rectally daily Stimulant laxative
Peripherally Acting Mu-Opioid Receptor Antagonists
Alvimopan (Entereg)
12 mg capsule
12 mg PO 0.5–5 h prior to surgery, followed by 12 mg BID beginning the day after surgery up to 7 days FDA approved for POI
200-fold selectivity for the peripheral opioid receptors
Poor GI/systemic absorption
REMS drug
Methylnaltrexone (Relistor)
8 mg, 12 mg injection
0.15 mg/kg SubQ daily or every other day FDA approved for chronic opioid-induced constipation, not POI. Does not affect opioid analgesic effects. Does not cross the blood-brain barrier. Discontinue all laxatives prior to use; restart laxatives PRN if suboptimal response to methylnaltrexone or naloxegol after 3 days
Naloxegol (Movantik)
12.5 mg, 25 mg tablet
25 mg PO daily
12.5 mg if 25 mg not tolerated
Prokinetic Agents
Erythromycin (Erythrocin)
250 mg, 500 mg tablet
500 mg injection
200–400 mg/5 mL oral suspension
IV: 3 mg/kg over 45 min q8h
PO: 250–500 mg (base) TID
Macrolide antibiotic with prokinetic activity
Off-label use; inconsistent data
Erythromycin ethylsuccinate 400 mg = erythromycin base or stearate 250 mg
Metoclopramide (Reglan)
10 mg injection
5 mg, 10 mg tablet
1 mg/mL oral solution
PO, IM, IV, SubQ: 5–10 mg BID–TID AC
PO route preferred
Prokinetic and antiemetic activity
Off-label use; inconsistent data
Decrease dose by 50% in CrCl <40 (IV) and CrCl ≤60 (PO)
Prucalopride (Motegrity)
1 mg, 2 mg tablet
2 mg PO daily
CrCl <30: 1 mg PO daily
ESRD on HD: avoid
Serotonin 5-HT4 receptor agonist
Off-label use
Start before surgery
ADR: headache, abdominal pain, nausea, diarrhea
Tegaserod (Zelnorm)
2 mg, 6 mg tablet
Females <65 years: 6 mg PO BID AC (dosing for IBSC or CIC) Serotonin 5-HT4 receptor agonist
FDA approved for emergency treatment of IBSC and CIC in women <55 years without alternative therapy option

AC, Before meals; ADR , Adverse drug reaction; BID , Twice daily; CIC , Chronic idiopathic constipation; CrCl , Creatinine clearance; ESRD , End stage renal disease; 5-HT4 , 5-Hydroxytryptamine receptor 4; FDA , Food and Drug Administration; GI , Gastrointestinal; HD , Hemodialysis; IBSC , Irritable bowel syndrome with constipation; IM , Intramuscular; IV , Intravenous; NSAID , Nonsteroidal anti-inflammatory drug; PO , Orally; POI , Postoperative ileus; PRN , As needed; REMS , Risk evaluation and mitigation strategies; SubQ , Subcutaneously; TID , Three times daily

Postoperative nausea and vomiting (PONV)


Nausea, vomiting, or retching in the immediate 24 postoperative hours.

Risk of PONV ( table 8.2 )

Table 8.2

Risk of PONV

Data from Apfel CC, Koivuranta EM, Greim CA, et al. A simplified risk score for predicting postoperative nausea and vomiting: conclusions from cross-validations between two centers. Anesthesiology . 1999;91(3):693–700.

Risk factors Female gender
History of motion sickness or previous PONV
Expected administration of postoperative opioids
No risk factor (low risk)
One risk factor (low risk)
Two risk factors (medium risk)
Three risk factors (medium risk)
Four risk factors (high risk)
10% of PONV
20% of PONV
40% of PONV
60% of PONV
80% of PONV

PONV , Postoperative nausea and vomiting

Management of PONV

Feb 28, 2021 | Posted by in EMERGENCY MEDICINE | Comments Off on Gastroenterology
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