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[Pharmacology](https://durgical.com/en/pharmacology/) · [Opioids and antagonists](https://durgical.com/en/pharmacology/classes/opioids-and-antagonists/)

# Oxycodone

A semi-synthetic oral μ agonist for severe pain, alone or combined with paracetamol. Its CYP3A4 metabolism exposes it to dangerous interactions.

Updated 2026-11-01

- Class: [Opioids and antagonists](https://durgical.com/en/pharmacology/classes/opioids-and-antagonists/)
- Receptor: μ-opioid receptor
- ATC code: N02AA05

## ⚠ High-alert medication

An error with this medicine can cause serious harm: double checks and protocols are used.

◎**μ-opioid receptor**Oxycodone

ⓘ The figure shows morphine in the μ receptor; oxycodone, a thebaine derivative, occupies the same site. There is no structure of oxycodone in the receptor.

**Target in 3D:** μ-opioid receptor. PDB structure 8EF6 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/8EF6) · Drag to rotate · pinch to zoom

## Mechanism of action

Oxycodone is a full μ-receptor agonist derived from thebaine. It activates the Gi protein, inhibits neurotransmitter release in the pain pathway and changes the emotional perception of pain; in the brainstem it depresses breathing and suppresses cough. A small part is converted to oxymorphone, which is also active.

- Activates the μ receptor in the spinal cord and brain
- The Gi protein reduces release of pain neurotransmitters
- Relief of severe pain by mouth
- In the brainstem: less drive to breathe, above all with other depressants

## Pharmacokinetics

**Absorption**
Well absorbed by mouth; immediate- and extended-release forms exist.

**Metabolism**
Liver: much of it is N-dealkylated to noroxycodone by CYP3A4; a smaller fraction is O-demethylated to oxymorphone.

**Elimination**
Kidney, as metabolites.

## Indications

- Pain severe enough to need an opioid when other options are not enough

## Adverse effects

### Common

- Nausea and vomiting
- Trouble sleeping
- Headache
- Weakness and tiredness
- Lower sexual desire

### Serious (rare, important)

- Life-threatening respiratory depression, above all at the start or after a dose increase
- Addiction, abuse and misuse, with risk of overdose and death
- Neonatal opioid withdrawal syndrome with prolonged use in pregnancy
- Adrenal insufficiency with prolonged use
- Severe hypotension

## Contraindications

- Significant respiratory depression
- Acute or severe bronchial asthma without monitoring or resuscitation equipment
- Known or suspected gastrointestinal obstruction, including paralytic ileus
- Hypersensitivity to the drug

## Key interactions

**CYP3A4 inhibitors (macrolides, azoles, ritonavir), or stopping inducers (rifampicin, carbamazepine, phenytoin)**
Raise opioid levels and can cause a fatal overdose.

**Benzodiazepines, alcohol and other central nervous system depressants**
Add up to profound sedation, respiratory depression, coma and death.

**CYP3A4 inducers, or stopping an inhibitor**
Lower its levels: weaker pain relief or withdrawal.

## What is monitored

- Respiratory rate and sedation
- Bowel habits
- Signs of misuse

## Administration and safety

- Extended-release forms are swallowed whole; crushing or chewing them releases a potentially fatal dose.
- Switching from immediate to extended release is not a one-to-one conversion: there is a risk of excessive sedation.
- Check whether the product contains paracetamol so the total allowed is not exceeded.
- Controlled medicine: the order is verified, every dose recorded and leftovers kept secure.

## Nursing care

- Before each dose: respiratory rate, oxygen saturation and sedation level; hold the dose and report excessive sedation or slow breathing.
- Keep naloxone at hand and teach the family to recognise an overdose.
- Prevent constipation from the start and track bowel habits.
- Prevent falls: dizziness, drowsiness and orthostatic hypotension.
- Teach the patient to lock the medicine away and dispose of leftovers safely.

## Pregnancy and breastfeeding

Prolonged use in pregnancy can cause neonatal opioid withdrawal syndrome, which is expected and treatable; the newborn is watched after birth.

## Memory aid

OXYcodone: «O» for Oral, «X» for eXtra strong. Block CYP3A4 and the dose shoots up.

## Test yourself

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

## Which enzyme metabolises most oxycodone, and what risk does that carry?

CYP3A4; its inhibitors (macrolides, azoles, ritonavir), or stopping inducers, can cause a fatal overdose.

## Why are extended-release oxycodone tablets never crushed?

Because the whole dose is released at once, which can be fatal.

## Which active metabolite does a small part of oxycodone form?

Oxymorphone, by O-demethylation.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/oxycodone/)

## Related drugs

- [Morphine](https://durgical.com/en/pharmacology/morphine/)
- [Hydrocodone](https://durgical.com/en/pharmacology/hydrocodone/)
- [Naloxone](https://durgical.com/en/pharmacology/naloxone/)

[← Back to the class: Opioids and antagonists](https://durgical.com/en/pharmacology/classes/opioids-and-antagonists/)

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

Sources: [Oxycodone: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682132.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [OXYCODONE HYDROCHLORIDE tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=928227bf-89c5-4c64-9823-0e84cc669388) (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 23 (McGraw Hill, 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=N02AA05) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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