[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Laxatives](https://durgical.com/en/pharmacology/classes/laxatives/) › Naloxegol

# Naloxegol

## Laxatives?

Laxatives

A PEG-linked naloxone that stays out of the brain. It blocks gut opioid receptors to treat opioid-induced constipation in chronic non-cancer pain.

Updated Nov 1, 2026

## Quick facts

**Group**
[Laxatives](https://durgical.com/en/pharmacology/classes/laxatives/)

**Target**
Mu-opioid receptor in the gut (peripherally restricted antagonist)

**Used for**
Opioid-induced constipation

**Key effects**
Abdominal pain · Nausea · Headache

**Monitor**
Bowel movements and abdominal pain

**ATC**
A06AH03

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Naloxegol is naloxone joined to a polyethylene glycol (PEG) polymer. PEG makes it a substrate of the P-glycoprotein efflux pump, so very little crosses the blood-brain barrier. It blocks mu-opioid receptors in the gut, which reverses opioid-induced slowing of the bowel, while central pain relief is largely kept.

- PEG keeps naloxegol out of the brain (P-gp efflux)
- It blocks mu receptors in the gut wall
- Opioid constipation eases; analgesia stays

## Indications

- Opioid-induced constipation in adults with chronic non-cancer pain

## Adverse effects

### Common

- Abdominal pain, diarrhoea, flatulence
- Nausea, vomiting
- Headache
- Sweating, chills, anxiety, irritability, yawning

### Serious (rare, important)

- Severe or worsening abdominal pain with diarrhoea (possible bowel injury)
- Allergic reactions: rash, swelling of face, lips or throat

## Contraindications

- Known or suspected intestinal obstruction
- Caution with conditions that weaken the gut wall: ulcers, Crohn's disease, diverticulitis, bowel cancer, Ogilvie's syndrome

## Key interactions

**Grapefruit and other CYP3A inhibitors**
Higher naloxegol levels; grapefruit is avoided

**St John's wort and other CYP3A inducers**
Lower naloxegol levels and less effect

**Other laxatives**
Usually stopped when naloxegol is started

## What is monitored

- Bowel movements and abdominal pain
- Signs of opioid withdrawal or loss of pain control

## Administration and safety

- Oral tablet, taken once a day before or well after the first meal; it can be crushed in water or given by nasogastric tube as instructed.
- Other laxatives are usually stopped when it is started.
- Stopped if the opioid is stopped.

## Pregnancy and breastfeeding

Human data are limited; use in pregnancy is discussed with the prescriber and needs a clear benefit.

## Nursing care

- Ask about bowel obstruction, ulcers, Crohn's disease, diverticulitis or bowel cancer before starting.
- Review the medication list for CYP3A inhibitors and inducers, and advise against grapefruit.
- Teach to stop and call for severe or worsening abdominal pain.
- Ask about sweating, chills or yawning (withdrawal-like symptoms) and pain control.

## Pharmacokinetics

**Metabolism**
Mainly hepatic CYP3A

**Elimination**
Metabolites mostly in faeces, some in urine

## Memory aid

«PEG keeps it in the gut»: naloxegol = naloxone + PEG, so the bowel moves and the pain relief stays.

## Test yourself

Think of the answer, then tap the question to see it.

## Why does naloxegol not block opioid analgesia in the brain?

Its PEG chain makes it a P-glycoprotein substrate, so little crosses the blood-brain barrier.

## Which fruit is avoided and why?

Grapefruit, because it inhibits CYP3A and raises naloxegol levels.

## Which condition is a contraindication?

Known or suspected intestinal obstruction.

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## Connections

## Related drugs 3

- [Alvimopan](https://durgical.com/en/pharmacology/alvimopan/)
- [Methylnaltrexone](https://durgical.com/en/pharmacology/methylnaltrexone/)
- [Naloxone](https://durgical.com/en/pharmacology/naloxone/)

[← Back to the class: Laxatives](https://durgical.com/en/pharmacology/classes/laxatives/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Naloxegol: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a615016.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=A06AH03) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/naloxegol/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/naloxegol/