Oxycodone
A semi-synthetic full mu-opioid agonist, similar to morphine, used for severe pain after surgery or injury and for cancer pain.
Drug card
- Class
- Opioid
- How it works
- Activating mu-opioid receptors in the brain and spinal cord to dull pain
- Used for
- Severe pain after surgery or injury
- Cancer pain
- Moderate to severe pain not eased by other painkillers
- Known for
- Constipation
- Slowed, shallow breathing (respiratory depression)
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does oxycodone work?
Oxycodone is a semi-synthetic, morphine-like full agonist, relatively selective for the mu receptor, with no ceiling to its pain relief. More of an oral dose survives first-pass metabolism than with most oral opioids. CYP3A4 turns it into noroxycodone and CYP2D6 into oxymorphone.
Like other opioid analgesics: Opioids activate mu-opioid receptors, the G protein-coupled receptors used by the body's own opioids in the brain, spinal cord and gut. In nerve cells this opens potassium channels and closes calcium channels, so neurons fire less and release less pain transmitter such as substance P. They also depress the brainstem breathing center, narrow the pupils and slow the gut; tolerance and dependence build with regular use.
Uses
What is oxycodone used for?
- Severe pain after surgery or injury
- Cancer pain
- Moderate to severe pain not eased by other painkillers
Side effects
Side effects of oxycodone
- ConstipationKnown for
- Slowed, shallow breathing (respiratory depression)Known forSerious
- Nausea and vomiting
- Drowsiness
- Dizziness
- Headache
- Itching
- Trouble sleeping
- Confusion
- Addiction, misuse and dependenceSerious
- Withdrawal symptoms if stopped suddenly
- Low blood pressureSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- CYP3A4 inhibitors, or stopping a CYP3A4 inducer, can raise levels to a fatal overdose.
- Benzodiazepines, alcohol and other CNS depressants add to sedation and breathing depression.
- Contraindicated in significant respiratory depression, acute severe asthma without monitoring, and bowel obstruction.
Good to know: Its oral bioavailability is high, 60 to 87%, compared with about 20 to 40% for oral morphine.
Remember it
A way to remember it
MORPHINE
- M
- Miosis (pinpoint pupils)
- O
- Opioid withdrawal if stopped suddenly
- R
- Respiratory depression
- P
- Pruritus (itching)
- H
- Hypotension
- I
- Intestinal slowing: constipation
- N
- Nausea and vomiting
- E
- Euphoria, then dependence and addiction
Written for biofideX
Its class
Opioid analgesics
Easily mixed up with opioid antagonists, benzodiazepines and antimotility drugs.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Oxycodone hydrochloride tablets: label (DailyMed)
- Oxycodone (NCI Thesaurus)
- Oxycodone (NHS)
- Morphine sulfate extended-release tablets: label (DailyMed)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Pain, fever and inflammation
Oxycodone is one of 15 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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