The M523 pill is a prescription opioid pain medication that contains oxycodone hydrochloride and acetaminophen. It is commonly identified as a white, capsule-shaped tablet with “M523” on one side and “10/325” on the other. The “10/325” marking means the tablet contains 10 mg of oxycodone hydrochloride and 325 mg of acetaminophen.
Oxycodone is an opioid analgesic, meaning it works on opioid receptors in the brain and body to reduce pain. Acetaminophen, also known as Tylenol, is a non-opioid pain reliever that can also reduce fever. Together, these medications may be prescribed for pain severe enough to require an opioid when other treatment options are not adequate.
Although the M523 pill may be legally prescribed, it carries serious risks. Oxycodone can cause dependence, addiction, slowed breathing, overdose, and withdrawal. Acetaminophen can also cause liver damage when taken in high doses or combined with other acetaminophen-containing products.
What Is the M523 Pill?
The M523 pill is a combination medication containing oxycodone and acetaminophen. According to DailyMed, each 10 mg/325 mg tablet contains oxycodone hydrochloride 10 mg and acetaminophen 325 mg. The same drug label describes it as a white to off-white caplet-shaped tablet debossed with “M523” on one side and “10/325” on the other.
Is the M523 Pill Percocet?
This medication is sometimes compared to Percocet because Percocet is also a brand-name combination of oxycodone and acetaminophen. However, a pill should never be assumed safe or legitimate based on appearance alone. Counterfeit pills can be made to look like real prescription medications.
M523 Pill at a Glance
| Category | Details |
|---|---|
| Pill imprint | M523 on one side and 10/325 on the other |
| Color and shape | White, capsule-shaped tablet |
| Medication type | Prescription opioid pain medication |
| Active ingredients | Oxycodone hydrochloride and acetaminophen |
| Strength | Oxycodone hydrochloride 10 mg / acetaminophen 325 mg |
| Drug class | Opioid analgesic combination |
| Common comparison | Often compared to Percocet because both contain oxycodone and acetaminophen |
| Main use | Pain severe enough to require an opioid medication when other options are not adequate |
| Addiction risk | Yes. Oxycodone can lead to misuse, dependence, addiction, withdrawal, and overdose |
| Major safety concern | Slowed breathing, overdose risk, and liver damage from too much acetaminophen |
| Counterfeit risk | Pills bought outside a licensed pharmacy may be fake and could contain fentanyl or other dangerous substances |
| Safe-use reminder | Only take this medication if it was prescribed to you and dispensed by a licensed pharmacy |
M523 Pill vs. Other 10/325 Oxcodone/Acetaminophen Pills
The M523 pill is one version of oxycodone/acetaminophen 10/325, but it is not the only pill with this same strength. Different manufacturers may produce oxycodone/acetaminophen tablets with different imprints, shapes, or appearances while still containing the same active ingredients: 10 mg of oxycodone hydrochloride and 325 mg of acetaminophen.
| Pill Type | What It Usually Means |
|---|---|
| M523 10/325 | A generic oxycodone/acetaminophen tablet containing 10 mg oxycodone and 325 mg acetaminophen |
| Percocet 10/325 | A brand-name version of oxycodone/acetaminophen 10/325 |
| Other generic 10/325 pills | May contain the same strength but have different imprints, colors, shapes, or manufacturers |
| Counterfeit 10/325 pills | May be made to look like real oxycodone/acetaminophen but could contain fentanyl or other dangerous substances |
The main difference between M523 and other legitimate 10/325 oxycodone/acetaminophen pills is usually the manufacturer and pill imprint, not the active ingredient strength. For example, one pharmacy may dispense a tablet marked M523, while another may dispense a different generic version with another imprint. Both may be legitimate if they come from a licensed pharmacy and match the prescription.
However, appearance alone cannot confirm that a pill is safe. Counterfeit pills can be pressed to look like real prescription opioids, including oxycodone and Percocet-style tablets. Any 10/325 pill that was not prescribed to you or dispensed by a licensed pharmacy should be treated as unsafe.
This is especially important because oxycodone/acetaminophen 10/325 is a high-strength opioid combination tablet. Taking multiple tablets, combining them with alcohol or sedatives, or using pills from an unknown source can increase the risk of overdose, respiratory depression, liver damage, and addiction.
What Is M523 Used For?
M523 may be prescribed to manage moderate to severe pain when an opioid medication is considered necessary. It may be used after surgery, injury, or for certain pain conditions under medical supervision.
This medication should only be taken exactly as prescribed. Taking extra doses, crushing or snorting the pill, mixing it with alcohol, or combining it with other sedatives can increase the risk of overdose.
Is M523 an Opioid?
Yes. M523 contains oxycodone, which is an opioid. Opioids can be effective for short-term pain control, but they also carry a risk of misuse, tolerance, physical dependence, addiction, and overdose.
Tolerance means a person may need more of the medication over time to feel the same effect. Dependence means the body has adapted to the drug and may experience withdrawal symptoms when use is reduced or stopped. Addiction, also called opioid use disorder, involves continued use despite harmful consequences.
Is the M523 Pill Addictive?
The M523 pill can be addictive because it contains oxycodone. Even when taken by prescription, oxycodone can lead to physical dependence. The risk may increase when the medication is taken for longer than prescribed, taken in higher doses, used for emotional relief, or combined with other substances.
Signs of a possible problem with M523 or other opioid medications may include:
- Taking more than prescribed
- Running out of medication early
- Craving the medication
- Feeling unable to function without it
- Visiting multiple doctors or pharmacies
- Using someone else’s prescription
- Crushing, snorting, or injecting pills
- Mixing opioids with alcohol, benzodiazepines, or other sedatives
- Withdrawal symptoms when trying to stop
If someone is worried about their opioid use, they should not try to quit suddenly without medical support. Opioid withdrawal can be extremely uncomfortable, and relapse after a period of reduced tolerance can increase overdose risk.
M523 Pill Side Effects
The M523 pill may cause side effects such as:
- Drowsiness
- Dizziness
- Nausea or vomiting
- Constipation
- Sweating
- Itching
- Headache
- Confusion
- Slowed reaction time
- Mood changes
More serious side effects can include slowed breathing, low blood pressure, fainting, severe sedation, liver injury, and overdose. Emergency help should be sought immediately if someone has trouble breathing, cannot stay awake, has blue or gray lips, makes gurgling sounds, or is unresponsive.
M523 and Acetaminophen Risks
Because M523 contains acetaminophen, taking too much can damage the liver. This risk is higher when a person takes multiple medications that contain acetaminophen, drinks alcohol, or takes more than prescribed.
Many cold, flu, pain, and sleep medications also contain acetaminophen. People taking M523 should check medication labels carefully and speak with a medical provider before combining it with other products.
Fake M523 Pills and Fentanyl Risk
One of the most serious risks today is counterfeit prescription pills. Fake pills may be pressed to look like real oxycodone, Percocet, Xanax, Adderall, or other medications. A pill bought online, from a friend, or from the street may contain fentanyl, nitazenes, methamphetamine, xylazine, or other dangerous substances.
The DEA’s One Pill Can Kill campaign warns that counterfeit pills are often made to look like legitimate prescription medications. The DEA reported seizing more than 47 million fentanyl-laced counterfeit pills in 2025, along with nearly 10,000 pounds of fentanyl powder.
Because counterfeit pills can look nearly identical to real medication, visual identification is not enough to confirm safety. The only safe source of prescription medication is a licensed pharmacy with a valid prescription.
M523 Withdrawal Symptoms
When someone becomes physically dependent on oxycodone, stopping suddenly may cause withdrawal symptoms. These may include:
- Anxiety
- Sweating
- Muscle aches
- Runny nose
- Watery eyes
- Nausea
- Vomiting
- Diarrhea
- Insomnia
- Restlessness
- Chills
- Strong cravings
Withdrawal is one reason many people continue taking opioids even after they want to stop. Medical detox and treatment can help reduce discomfort, manage cravings, and lower the risk of relapse.
When M523 Pill Use Becomes a Problem
Not everyone who takes M523 develops an addiction. However, opioid use can become dangerous when a person feels unable to control their use or continues taking the drug despite consequences.
It may be time to seek help if M523 use is affecting someone’s health, family, work, finances, mental health, or safety. It is also important to seek help if someone is using counterfeit pills, combining opioids with other substances, or has experienced an overdose.
Treatment for M523 and Opioid Addiction
Opioid addiction is treatable. At Brooks Healing Center, we help individuals address the physical, emotional, and behavioral aspects of substance use. Treatment may include medical support and medication-assisted treatment, therapy, relapse prevention planning, trauma-informed care, and ongoing recovery support.
For many people, opioid addiction is not simply about the pill itself. It may involve chronic pain, anxiety, depression, trauma, grief, stress, or long-term patterns of substance use. Effective treatment looks at the whole person, not just the substance.
Recovery from opioid addiction is possible with the right support. If you or someone you love is struggling with M523, oxycodone, Percocet, fentanyl, or other opioids, reaching out for help can be the first step toward safety and healing.
Frequently Asked Questions About the M523 Pill
What is the M523 pill?
The M523 pill is a prescription medication containing oxycodone hydrochloride 10 mg and acetaminophen 325 mg. It is typically a white, capsule-shaped tablet marked “M523” on one side and “10/325” on the other.
Is the M523 pill the same as Percocet?
M523 contains the same type of active ingredients found in Percocet: oxycodone and acetaminophen. However, Percocet is a brand name, while M523 is an imprint associated with a specific generic oxycodone/acetaminophen tablet.
Is M523 a narcotic?
Yes. M523 contains oxycodone, which is an opioid narcotic pain medication. It is a controlled substance due to its potential for misuse, dependence, addiction, and overdose.
Can M523 cause overdose?
Yes. M523 can cause overdose, especially when taken in high doses, mixed with alcohol or sedatives, or used with other opioids. Counterfeit versions may also contain fentanyl or other potent synthetic opioids, which can greatly increase overdose risk.
Can you quit M523 cold turkey?
Stopping M523 suddenly may cause opioid withdrawal if the body has become dependent on oxycodone. People who have been taking opioids regularly should speak with a medical professional about a safe taper or detox plan.
What should I do if I find an M523 pill?
Do not take any pill that was not prescribed to you. If the pill is not from a licensed pharmacy, there is no reliable way to confirm what it contains based on appearance alone.
Sources
- DailyMed. (n.d.). Oxycodone hydrochloride and acetaminophen tablet. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=77a4aae7-a0cc-4f86-b91f-ec4112c6d3be
- DailyMed. (n.d.). Label: Oxycodone and acetaminophen tablet. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=916ff456-a27e-49dc-a312-274126a8c30c
- Drugs.com. (n.d.). M523 10/325 pill: White, capsule/oblong, 16mm. https://www.drugs.com/imprints/m523-10-325-6767.html
- U.S. Drug Enforcement Administration. (n.d.). One Pill Can Kill. https://www.dea.gov/onepill
- U.S. Food and Drug Administration. (2011, January 14). Prescription drug products containing acetaminophen: Actions to reduce liver injury from unintentional overdose. Federal Register. https://www.federalregister.gov/documents/2011/01/14/2011-709/prescription-drug-products-containing-acetaminophen-actions-to-reduce-liver-injury-from
- Orandi, B. J., Emamian, S., Kaminski, M., Tavakoli, A., & Segev, D. L. (2023). Association of FDA mandate limiting acetaminophen in prescription combination opioid products and subsequent hospitalizations and acute liver failure. JAMA, 329(9), 735–743. https://pmc.ncbi.nlm.nih.gov/articles/PMC9993184/
- Centers for Disease Control and Prevention. (2025, June 11). Lifesaving naloxone. https://www.cdc.gov/stop-overdose/caring/naloxone.html
- Centers for Disease Control and Prevention. (2024, April 2). What to do if you think someone is overdosing. https://www.cdc.gov/stop-overdose/response/index.html
- Substance Abuse and Mental Health Services Administration. (2025, August 25). Treatment options for substance use disorder. https://www.samhsa.gov/substance-use/treatment/options
- Substance Abuse and Mental Health Services Administration. (2021). TIP 63: Medications for opioid use disorder. https://library.samhsa.gov/product/tip-63-medications-opioid-use-disorder/pep21-02-01-002
