Alvimopan
Entereg
Peripherally-acting mu-opioid receptor antagonist (PAMORA)
Blocks GI mu-opioid receptors WITHOUT crossing the blood-brain barrier → reverses opioid-induced gut slowing while preserving central analgesia. Accelerates return of bowel function.
Indications
- •Accelerate GI recovery after bowel resection with primary anastomosis (postop ileus prevention — ERAS)
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Bowel surgery | 12 mg PO 30 min–5 h before surgery, then 12 mg BID ×7 days (max 15 doses, inpatient only) | — |
Pharmacokinetics
Poorly absorbed (acts locally in gut). Given short-term perioperatively.
Side effects
- !MI signal with long-term use (Black Box — restricted to short inpatient use, REMS)
- !Not for chronic opioid users >7 days (↑ GI adverse effects)
Contraindications
- ×Therapeutic opioids for >7 consecutive days immediately prior
- ×Severe hepatic/renal impairment
Clinical pearls
- ★ERAS staple for bowel resection — shortens ileus by antagonizing gut opioid receptors without touching analgesia.
- ★Short-term inpatient use only (REMS) due to a cardiovascular signal in long-term studies.
Other drugs in Others
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- Hydroxocobalamin
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- Octreotide
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- Phentolamine
Competitive, reversible α1 + α2 blockade → vasodilation. Short-acting.
- Inhaled Nitric Oxide
Inhaled NO diffuses to pulmonary vascular smooth muscle → ↑ cGMP → SELECTIVE pulmonary vasodilation only in VENTILATED lung units (improves V/Q matching). Inactivated by hemoglobin before reaching systemic circulation → no systemic hypotension.
- Digoxin Immune Fab
Ovine Fab fragments bind free digoxin → the complex is renally excreted → rapidly reverses digoxin/digitoxin toxicity.
- Aminophylline
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Browse all classes: /reference/drugs
Suggested reading
- •Miller's Anesthesia, 9e
- •FDA package insert
