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Table 3 Information about opioid antagonists

From: The effect of opioids on gastrointestinal function in the ICU

Opioids antagonists

Mechanism of action

Administration

Recommended dose

Approved indication

Side effects

Contraindications

Methylnaltrexone

PAMORA

Subcutaneous injection

Oral

8 mg (BW 38–62 kg)

12 mg (BW 63–114 kg)

0.15 mg/kg for patients with weights outside of these ranges

OIC patients, lower GI paralysis, insufficient response to laxatives

GI Perforation abdominal pain, nausea, diarrhea, flatulence

Known or suspected mechanical GI obstruction, perforation

Alvimopan

PAMORA

Oral

12 mg BID (limited to 15 doses)

Postoperative ileus, partial bowel resection, primary anastomosis

MI, anemia, dyspepsia, hypokalemia, back pain, urinary retention

Opiate use > 1 week

Naloxegol

Antagonist of DOR, KOR and MOR

Oral

12.5–25 mg OD

OIC in non-cancer and chronic pain patients, inadequate response to laxative therapy

Nausea, vomiting, diarrhea, abdominal pain, and bowel obstruction, flatulence, MI and QT prolongation less than Alvimopan

Patients with known or suspected GI obstruction are at increased risk of perforation

Naloxone

Opioid receptor antagonist mediated both peripheral and central

Oral

3–12 mg TID

Constipation, lower GI paralysis

Symptoms of opioid withdrawal, reversal of analgesic

Hypersensitivity to the drug

Naldemedine

Peripherally acting DOR, KOR and MOR antagonist

Oral

0.2 mg OD

OIC patients

Abdominal pain, diarrhea, nausea, gastroenteritis

Suspected or known GI perforation, obstruction and severe hepatic disease

  1. PAMORA peripherally acting mu opioid receptor, MOR mu opioid receptor, DOR delta opioid receptor, KOR kappa opioid receptor, BID twice per day, TID three times per day, BW body weight, OD once per day, MI myocardial infarction, OIC opioid-induced constipation