How does oxycodone work?

Oxycodone works by binding to mu, kappa and delta receptors in the central nervous system. More on how oxycodone works and how it affects the brain here.

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Experts do not know exactly how oxycodone works.

But, in general, oxycodone alters your perception and emotional response to pain by binding to opioid receptors in the central nervous system (this is how people get high on oxy).   More here on how quickly and how long oxycodone works, plus how you can possibly optimize oxycodone to make it work better. We invite you to ask your questions about oxycodone at the end.

How does oxycodone affect the brain and nervous system?

Although experts do not know exactly HOW oxycodone works, they do know that pain relief occurs through chemical processes in the central nervous system. And although the precise mechanism of analgesic action is unknown, opioid-induced pain relief occurs without loss of consciousness and is very useful as a pain management therapy. So what’s important to know about oxycodone and your brain? And what adverse side effects can occur in the nervous system as a result of taking oxycodone?

Oxycodone affects the brain and nervous system by acting in the same way as other opioids. Oxycodone binds to mu, kappa and delta receptors in the central nervous system, inhibits adenylyl-cyclase and hyperpolarisation of neurons, and decreases excitability. Opiate agonists like oxycodone do not alter the threshold or responsiveness of nerve endings to stimuli nor the conduction of impulses along peripheral nerve. Instead, oxycodone alter the perception of pain at the spinal cord and higher levels in the central nervous system (substantia gelatinosa, spinal trigeminal nucleus, periaqueductal gray, periventricular gray, medullary raphe nuclei, hypothalamus) as well as your emotional response to pain. The most common results are pain relief and euphoria, the main reason behind oxycodone addictive effect.

However, oxycodone also affects other parts of the brain and nervous system. In addition to pain relief, oxycodone stops the cough reflex, slows breathing and causes the pupils to dilate. Opioids like oxycodone also have the ability to lower body temperature and to suppress opiate withdrawal. The two other significant effects of oxycodone on the nervous system are:

Respiratory depression – Oxycodone also produces respiratory depression (slowed breathing) by direct action on brain stem respiratory centers. Slowed breathing involves a reduction in the responsiveness of the brain stem respiratory centers to both increases in carbon dioxide tension and to electrical stimulation and can cause death in cases of oxycodone overdose.

Suppressed cough – oxycodone is an antitussive, or cough suppressant. Oxycodone depresses the cough reflex by direct effect on the cough center in the medulla.

How does oxycodone work in the body?

Oxycodone is a powerful pain reliever, that works in the body by affecting the central nervous system (see below). Most people use oxycodone for pain relief, although it is also prescribed (less frequently) as a cough suppressant. Side effects for taking oxycodone are those common to opioids and include mainly:

  1. constipation
  2. drowsiness
  3. nausea

Vomiting, itchy skin and dizziness are less common. The intensity of these side effects tends to decrease over the course of time as tolerance to oxycodone builds.

How fast or quickly does oxycodone work?

How fast oxycodone works depends upon what version of oxycodone you take and how you take it.   For example, if you are take oxycodone orally as prescribed, controlled release versions of oxycodone start to work a little more slowly than immediate release versions.  If, however, you chew, crush, snort or inject either version of oxycodone, effect is near immediate. These modes of administration significantly increase the risk of oxycodone addiction, adverse side effects and overdose and are never medically recommended.  Still, keep in mind that how much oxycodone can you take at once depends upon your exposure to opiates.

Controlled release oxycodone onset of effects – Oxycodone CR effects usually begin one hour after oral administration.

Immediate release oxycodone onset of effects – Analgesic effect occurs within 10-15 minutes for immediate release oxycodone (following oral administration of conventional preparations of oxycodone).

How long does oxycodone work?

Controlled release oxycodone duration of action  – Extended-release tablets of oxycodone are formulated to provide controlled delivery of oxycodone and oxycodone CR effects last for about 12 hours. This is why doctors usually prescribe oxycodone extended release tablets only twice daily.

Immediate release  oxycodone duration of action – Immediate release oxycodone reaches its maximum therapeutic levels in 30-60 minutes, and persists for 3-6 hours. This is why doctor usually prescribe immediate release oxycodone every 4-6 hours, as needed.

Can oxycodone work better?

Yes, it’s possible to get more pain relief for longer while taking oxycodone.  But keep in mind that the minimum effective plasma concentration of oxycodone to achieve analgesia varies widely. Plus, the minimum effective concentration of oxycodone for any person may increase with repeated dosing due to an increase in pain and/or development of tolerance. So, to make oxycodone work better, be sure first that your doctor has prescribed you with appropriate oxycodone doses that account for your pain threshold and tolerance to opioids.

Second, if you are taking immediate release oxycodone, you can eat a high fat meal at the same time that you take oxycodone. Both oxycodone bioavailability and peak plasma oxycodone concentration are significantly altered by consumption of a high-fat meal. In other words, your body absorbs more oxycodone and will feel the effects of oxycodone longer when you take immediate release oxycodone with high fat.

Finally, special populations need to take care when considering oxycodone for therapeutic use. Children and those with liver/renal failure have a unique oxycodone pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.

Does oxycodone work for everyone?

No. Opioid pain killers like oxycodone are not for everyone. Although analgesic effect can occur, some adverse side effects may not be manageable. And there is always the risk of developing dependence on oxycodone, or addiction to oxycodone.

If you still have questions about how oxycodone works or how to use oxycodone, please leave them here. We do your best to answer all legitimate questions with a personal and prompt reply.

Reference Sources: Daily Med: Oxycodone hydrochloride
Daily Med: Oxycodone hydrochloride controlled release
TOXNET: Oxycodone
PubMed: Oxycodone: a pharmacological and clinical review
PubMed: The pharmacokinetics of oxycodone
PubMed: Differential effects of food on the bioavailability of controlled-release oxycodone tablets and immediate-release oxycodone solution
About the author
Lee Weber is a published author, medical writer, and woman in long-term recovery from addiction. Her latest book, The Definitive Guide to Addiction Interventions is set to reach university bookstores in early 2019.


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  1. My husband has been taking oxys for 8 years at the beginning it’s for his back pains and then he overdose it and tried everything to quit but not success. Then he went to hospital to get clean but after six months he is hood up again. It’s been on and off the past eight years. And now he is taking 40pills in the morning and 40pills in the afternoon and he is pretty convinced that he tried to be careful and there’s no problem with that.
    He said his brain had changed after he took the medicine at the first place and it’s pretty much part of his life. So my question is the way he is taking the oxys is it really safe? Is it very dangerous? Is there any article explaining more clearly how long you are using it related to how much affects on you? And will the way he takes the drugs affect his sperm if we want to have a baby?

  2. I have been taking Oxycodone 20mg 4 times a day and 40 mg oxycontin 2 times a day for 10yrs..My insurance wants to switch to the new drugs Embeda and Hysingla and Xtampzal I’m worried about changing drugs and what kinda of side effects we will find out about these new drugs 10 yrs from now.I have had no problems with what I’m use to taking.Can you tell me about these new drugs and if they will work for pain as good as the meds I’m taking now.

  3. I take oxy 4 times a day and am freezing all the time! I also have swelling in both legs from knee down to bottom of my feet!

  4. I take 10 mg oxycodone at 5 am noon and 6pm. How much will show up in a blood test after 14 hours without any ingested?)

    1. Hi Reina. I suggest that you speak with your doctor about the time and dosage of taking oxycodone.

  5. Jake….constant pain will wear on you. Wear on you to the point of “anti-socialism” not enjoying what you would consider to be normal. I too am suffering from this “fatigue syndrome” (I hate being labeled with a condition that is un-treatable), OX will hit you where you live, respiratory is how you live, shortness of breath will effect you in ways you wouldnt believe. IE; anti-social, cannot, do not feel, you can complete your task’s. The anti-social because , not that you don’t care, your not out there doing what you want, which is where your friends are? How is your temp? Check in the mornings and thru the day (and I mean as your eyes open check it and keep a log)…also diligently do your yearly blood work and compare looking for anomalies…WBC etc.

  6. I’m taking oxycodone for pain. Surgery is planned but I will have been on them for 2 months. I’m 71. Once I’m over the surgery & pain can I just stop taking them or do I have to taper off or will I be addicted & have withdrawal? I’ve never been on opiads or other serious drugs.

  7. I was prescribed oxy quick release for break through pain. This pain has, in the past, been controlled by Dilaidid injections in ER, yet NEVER from the oxy. I tried explaining to my pain mgmt team that it was not working, yet they continued to prescribe. As I DID notice an elevation in my ability to be active, to my normal self, nothing ballistic or crazy, I decided, as long as they were handing it out without question, I would fill them and, as I knew they would not receive the severe sudden onset of pain attacks, I would simply just take them once a day so as to be able to continue with daily activity in a normal manner. I was prescribed 20mg pills and take two a day, separately, not together. In all honesty, I have thrown out many hundred over the past 3 years, before I was really bothering to take them, but now, I do not toss them, but “set them back”. I was always aware of the addiction factor, but thought the addiction was purely physical. I’ve come to believe the addiction results are, infact, so very much more than physical. I’m not a creep or criminal. I’m not getting them from anywhere,I simply fill my script for 75 every month. I am quite certain that I AM addicted. While I have never been social, I HAVE always filled my days with things I loved to do and was very passionate about…yet in the last four months, I cannot seem to derive pleasure from anything. This did, infact, occur quite innocently…I had lost half my body weight (dropped to 60 pounds) and I simply wanted to have the energy to do the things I once did. And, as I was taking MUCH LESS than prescribed, I thought I was OK. I AM NOT OK, yet, I also am not many many of the signs that are called out here as addictive. I don’t jones for it. I’m not sweaty cold agitated etc. I simply just seem to have no passion for anything. No desire to do anything that used to bring me so much pleasure. I’ve been seeking to find if this is due to oxy use over the past three years and I do believe it is. Maybe I am just now beginning the addiction cycle and the other things will follow…but I don’t want that. I want my life back. Does what. Am going thru sound like oxy addiction (brain effects?) to you? I mean, I hesitate to say I am depressed because I do not feel sad…I just feel nothing. Any help would be greatly appreciated.

  8. I have been prescribed Percocet 10/325 for nerve pain in my right let due to lumbar fusion surgery. I am taking 4 per day. My question is do you take the meds to stop the pain, or to prevent it? Does it build in your system to keep the pain at bay, or should you only take the meds as needed for the pain? Thanks in advance for any help with this.

    1. Hi Diana. Use your medication only as prescribed by a doctor. Sometimes the meds are used to stop the pain, otherwise to prevented. All depends form the patient and the pain s/he got.

  9. why does oxycontin relieve pain from syringiomielia and not from pain in leg caused by arthritis in my spine. The pain radiates down my leg and into my ankle and is constant. i get complete relief from oxycontin from the pain in my neck caused by syrinyx

  10. Hello Linn. Thanks for your question. I’m not sure how to respond, though…are you looking for warning signs of a potential relapse? Or ways that people in recovery have similar personalities? Can you be a little more precise in what you’re looking for?

  11. Hi, I have a friend who has been clean since 2011 from Oxycotin. What are some of the recovering characteristics to expect of her personality? Thanks for this info.

  12. Hello, I have had many parts of my cerebellum removed and have a shurt inserted to manage my brain pressure. Can Oxycodone increase my brain pressure? And if so, how much brain pressure is the limit become complications?

  13. Hi Devon. Usually, if you take oxycodone and someone looked at your eyes they may see that your pupils were extremely small. Doctors call this “pinpoint pupils”, and this symptom is a side effect of taking the central nervous system depressant. But dilated pupils can also be a sign used to help identify an oxycodone overdose. So while it doesn’t ALWAYS occur, pupil dilation can occur when you’re taking oxycodone and can also be a sign that you’ve taken TOO MUCH oxycodone.

  14. I’m a bit confused on the wording used in describing some side effects of oxycodone. I’m not a medical professional, but in the paragraph right before respiratory depression it says that oxycodone causes pupil dilation. Is this a typo, because I’ve seen people using oxycodone recreationally before and this is never the case?

  15. I sldo noticed the last comment. So oxycodone can lower bpdy temperatures. Could this add to the problems of Reynaud cold toes>

  16. Does Oxycodone create carbon monioxide poisioning in the body? I noticed part of the article that mentioned carbon monoixide.

  17. Hello jackeller. If you have heart problems and are taking oxycodone for chronic pain, it does seem that the combination can affect your circulation. I’d suggest that you bring this symptom to your prescribing doctor. Perhaps there are exercises which can increase circulation throughout the body (qi gong, yoga, breath work) and help you manage the discomfort of being cold.

  18. will long term use of perocet (oxycodone) cause your body to be cold even with temp turned up. i have been taking perocet for years for a back injury and for spilal stonaus. i stay cold most of the time . if i sleep with lower temp. in house i cannot get awake in the morning and i am always tired ,but if temp. is hot 75*-76* i can wake up get right up feel fine lots of enegry. i don’t take more than perscribed. i usually have 50-70- left at the time for the next visit,i have been this way since i had my aorta reolaced in 2008. i have that problem and thyroid problem along with other bothersome ailments lass agervating.

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