What is a White M366 Pill?

If you’ve found an oval pill that is white with the characters “M366” marked on one side, you’ve likely found a prescription medication that contains acetaminophen (a pain reliever and fever reducer) and hydrocodone (a prescription opioid). While effective in managing pain, this medication carries a high risk for misuse, dependence, and overdose, especially when people take it more frequently or in higher doses than prescribed.

In this article, we’ll break down what the M366 pill is, what it’s used for, potential side effects, and how to find treatment if you’re struggling with addiction. For immediate assistance with addiction or mental health issues, or to speak with an addiction specialist, please reach out to our team at Moving Mountains Recovery today.

What is a White Pill Marked M366?

A white oval pill that is marked “M366” on one side likely contains acetaminophen and hydrocodone. 

Acetaminophen is a commonly used pain reliever and fever reducer that many Americans keep in their medicine cabinets. When formulated by itself, acetaminophen is available over the counter. According to the Food and Drug Administration (FDA), acetaminophen is found in over 600 over-the-counter and prescription drugs in the U.S., both to treat pain and reduce fevers.

Hydrocodone, on the other hand, is a prescription opioid pain reliever. It works by binding to opioid receptors in the brain and spinal cord to block pain signals and reduce the sensation of pain. Because it can cause feelings of euphoria, it also has a high potential for misuse and addiction.

The combination of acetaminophen and hydrocodone is typically prescribed to manage moderate to severe pain. Hydrocodone typically provides stronger pain relief than acetaminophen, but the two active ingredients work together to provide more pain relief than they would if taken by themselves. However, it’s important to take this medication exactly as prescribed, as taking too much can lead to serious side effects, including liver damage from acetaminophen or overdose from hydrocodone.

There are many variations of pills that contain both hydrocodone and acetaminophen. A white oval pill with “M366” markings contains 325mg of acetaminophen and 7.5 mg of hydrocodone.

Common Uses for M366 Pills

The M366 pill is an opioid frequently prescribed to treat moderate to severe pain. It may be used in instances of chronic pain, but it’s most often used after surgery or to manage acute pain. It’s typically dosed every four to six hours, as needed, to alleviate pain. 

Potential uses include:

• Pain management following surgery
• To alleviate injury-related pain
• Manage severe dental pain, such as after a tooth extraction
• Chronic pain conditions like back pain or arthritis (when other treatments and pain management strategies fail to provide effective pain relief)
• For cancer-related pain management

Because M366 contains hydrocodone, it’s typically only prescribed when other non-opioid pain relievers aren’t strong enough. It’s important for patients to use this prescription medication under close supervision due to the risk of dependence, tolerance, and side effects. 

Be sure to tell your doctor if you have a medical history of opioid use disorder or other forms of substance abuse issues. In 2021, the National Institute on Drug Abuse (NIDA) estimated that about 5.0 million people aged 12 and older in the U.S. had a prescription opioid use disorder.

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Is the M366 Pill a Controlled Substance?

The M366 pill contains hydrocodone, which is a prescription opioid used for pain relief. Like most other prescription opioids, hydrocodone is a Schedule II Controlled Substance according to the U.S. Drug Enforcement Administration (DEA). This means it has a recognized medical use but also carries a high potential for abuse, which can lead to severe psychological or physical dependence.

Take caution while taking the M366 pill, and only take it as directed.

Side Effects of the White M366 Pill

Acetaminophen and hydrocodone can both cause side effects, especially when taken in high doses or for extended periods of time. Some side effects are mild and manageable, while others can be more serious and require medical attention.

Common side effects include:

• Drowsiness or dizziness
• Nausea or vomiting
• Constipation
• Lightheadedness
• Headache

More serious side effects may include:

• Shallow or slowed breathing
• Confusion or difficulty thinking clearly
• Low blood pressure
• Liver damage (especially if taken with other products containing acetaminophen or alcohol)
• Signs of allergic reaction, like rash, itching, or swelling
• Respiratory depression (in high doses or mixed with other CNS depressants)

Everyone reacts differently, and some people may not experience side effects at all. If something feels off or you experience difficulty breathing, severe respiratory depression, or the inability to stay awake, be sure to seek medical attention right away.

How Long Do the Effects of M366 Pills Last?

The effects of M366 pills typically last between 4 and 6 hours, depending on your body, dosage, and how often you take it. Most people start to feel relief within 30 to 60 minutes after taking the pill, with peak effects occurring around the 1-hour mark.

Keep in mind that hydrocodone’s pain-relieving effects may wear off before it’s fully out of your system. Just because the pain comes back doesn’t mean it’s safe to take more. Always stick to your prescribed schedule. Taking more than prescribed dosages too soon can lead to overdose and other adverse reactions.

Risks of Misuse

In 2023, the National Survey on Drug Use and Health found that 3.6 million people that year misused hydrocodone.

The white, oval M366 pill is an addictive opioid. It’s true that it’s effective in managing pain, but if it’s misused, it can be highly addictive and pose numerous health risks. 

Risks associated with misusing M366 pills include:

Opioid Dependence and Addiction

Hydrocodone is a powerful opioid, and taking it in ways other than prescribed, such as taking higher doses, using it more often, or crushing and snorting the pills, can quickly lead to physical dependence and addiction.

Misuse can also raise your tolerance, meaning you need more of the drug to feel the same effects, which increases the risk of overdose. You may also begin having withdrawal symptoms if you don’t take hydrocodone, such as muscle aches, anxiety, nausea, sweating, and trouble sleeping. These symptoms can be uncomfortable and make it harder to stop without help.

Liver Damage

Although acetaminophen is an over-the-counter medication, it does come with risks, particularly in higher doses. One of these risks is the potential for liver damage.

The maximum safe daily dosage of acetaminophen is 4,000mg. Exceeding this amount can damage your liver and other organs.

Early signs of liver damage may include nausea, fatigue, and yellowing of the skin or eyes.

Overdose Risk

Misusing M366 can depress your central nervous system to dangerous levels, leading to slow or stopped breathing, unconsciousness, or death. The risk is even higher when combined with alcohol, benzodiazepines, or other sedatives.

Unfortunately, NIDA reports that approximately 14,716 people died as a result of a prescription opioid overdose in 2022.

Impaired Mental and Physical Abilities

Misuse can cause significant impairment in judgment, coordination, and reaction time, increasing the risk of accidents and injuries. This can affect everyday activities like driving, operating machinery, or even walking safely.

Social Consequences

Using, possessing, or distributing prescription opioids like M366 pills without a valid prescription is illegal and can result in fines, arrest, or imprisonment. Misuse can also impact your employment, relationships, and reduce your overall quality of life.

Drug Interactions and Precautions to Consider When Taking The M366 Pill (Acetaminophen/Hydrocodone Bitartrate)

M366 pills can interact with several other medications and substances, which may increase the risk of serious side effects or reduce their effectiveness. It’s important to let your healthcare provider know about all the medications, supplements, or substances you’re using before starting this medication.

Harmful drug interactions can occur when using M366 pills with the following:

• Alcohol – Avoid drinking alcohol while taking hydrocodone and acetaminophen. Alcohol can amplify the effects of hydrocodone, potentially leading to an overdose, and it can increase the risk of liver damage due to the harsh effects of acetaminophen and alcohol on the liver.
• Other opioid analgesic medications – Combining multiple opioids can increase the risk of respiratory depression, sedation, overdose, and death. Do not take other prescription painkillers unless specifically approved by your doctor.
• Other central nervous system depressants – CNS depressants like benzodiazepines (e.g., Xanax, Valium), muscle relaxants, or sleep aids can dangerously enhance the sedative effects of hydrocodone. This combination may lead to extreme drowsiness, slowed breathing, coma, or death.
• Antidepressants and antipsychotic medications – Some medications that affect serotonin levels (like SSRIs, SNRIs, MAOIs) may increase the risk of serotonin syndrome, a rare but serious condition. Others can enhance sedation.
• Certain antibiotics or antifungals – Medications that inhibit liver enzymes (like erythromycin or ketoconazole) may affect how hydrocodone is processed in the body, potentially increasing its effects or side effects.

If you have been prescribed this medication, do not take more than the prescribed dose, especially due to the risk of liver damage from acetaminophen. You should also avoid driving or using heavy machinery until you know how the medication affects you.

Finally, be sure to store this medication in a secure place, out of reach of children or anyone who might misuse it.

Signs of Opioid Overdose

Taking M366 pills in higher doses than prescribed or combining them with other CNS depressants can result in a potentially life-threatening overdose.

Common signs of an opioid overdose include:

• Slow, shallow, or stopped breathing
• Extreme drowsiness or inability to wake up
• Limp body or unresponsiveness
• Blue or purple lips and fingernails
• Slow heartbeat or low blood pressure
• Gurgling or choking sounds

If you suspect someone is experiencing an opioid overdose, call 911 immediately and administer naloxone (Narcan) if available.

How Long Does the M366 Pill Stay in Your System?

Hydrocodone is a fast-acting opioid. The effects wear off within 4-6 hours, but it can be detected in your system for longer periods of time. 

Hydrocodone is the active opioid in M366 and is typically detectable in your system for:

• Blood tests: up to 24 hours after the last dose
• Urine tests: usually 2 to 4 days, depending on factors like your metabolism and how much you took
• Saliva tests: about 1 to 4 days
• Hair follicle tests: up to 90 days, though hair tests are less common for routine drug screening

The exact detection window for use of a M366 pill can vary based on your age, weight, liver and kidney health, hydration levels, and how frequently you take the medication. People who use hydrocodone regularly or in higher doses may find it stays in their system longer.

Hydrocodone Addiction Potential

Hydrocodone, the opioid in the M366 pill, carries a significant risk of addiction. While it’s effective for managing moderate to severe pain, hydrocodone works by binding to opioid receptors in the brain, which not only reduces pain but also produces feelings of euphoria or well-being. These effects can make it habit-forming.

Repeated use, especially in higher doses or for longer periods than prescribed, can lead to physical dependence and cravings. Over time, the brain adjusts to the presence of the drug, and you may need more of it to achieve the same effect (process called tolerance). This can quickly escalate into addiction, where using the drug becomes compulsive despite harmful consequences.

Common signs of hydrocodone addiction can include:

• Taking the M366 pill in larger amounts or for longer than prescribed
• Craving the drug or obsessing about its use
• Difficulty controlling or stopping use
• Neglecting responsibilities at work, school, or home
• Continuing use despite negative health or social effects

If you or a loved one is struggling with hydrocodone misuse or addiction, professional help is available. 

Do not wait to seek treatment if you have been abusing the M366 pill or another type of drug. Early intervention improves the chances of successful recovery and can help prevent serious health risks like overdose.

How Can The M366 Pill Help People Struggling With Chronic Pain?

For individuals living with chronic pain due to conditions like arthritis, back injuries, or nerve damage, this medication can offer a break from constant discomfort and improve quality of life.

When used as prescribed under the supervision of a healthcare provider, the M366 pill can help people regain mobility, participate in daily activities, and sleep better. These are things that often suffer when chronic pain goes unmanaged.

However, because it contains an opioid (hydrocodone bitartrate), this medication is usually recommended for short-term use or as part of a broader pain management plan.

Non-Opioid Options for Pain Relief

Patients suffering from chronic pain may be fearful to seek help for opioid addiction because they understandably do not want to be in pain. Thankfully, there are safer alternatives to the M366 pill that can provide similar, if not the same, pain relief as prescription opioids–and without serious risks.

Some safer alternatives include:

• Physical therapy – Targeted exercises and treatments can help strengthen muscles, improve flexibility, and reduce pain without medication. Over time, physical therapy can improve function and decrease reliance on painkillers.
• Buprenorphine or Suboxone – These medications are used both for opioid addiction treatment and pain management. They work differently from traditional opioids, providing pain relief with a lower risk of misuse and withdrawal symptoms.
• Alternative therapies – Techniques like acupuncture, massage, chiropractic care, and mindfulness meditation have helped many people manage chronic pain with fewer side effects.
• Non-opioid pain relievers – Over the counter drugs like acetaminophen (within safe limits) or NSAIDs such as ibuprofen can effectively manage mild to moderate pain.

Don’t be afraid to seek treatment if you need it. There are realistic options available.

Does Insurance Cover Opiate Rehab?

Yes, thanks to laws such as the Affordable Care Act (ACA) and the Mental Health Parity and Addiction Equity Act (MHPAEA), insurance must cover addiction treatment. These laws require most insurance providers to offer the same level of coverage for substance use and mental health disorders as they do for physical health conditions.

Coverage can vary depending on your insurance plan, but many plans include services such as detox, inpatient rehab, outpatient treatment, therapy, and medication-assisted treatment (MAT) for opioid use disorder. You may still be responsible for copays, deductibles, or prior authorizations, so it’s a good idea to contact your insurance provider or the rehab center directly to verify what’s covered under your plan.

To find out your insurance plan’s details and whether or not it will cover addiction treatment, reach out to Moving Mountains Recovery for a confidential, risk-free insurance verification with one of our admissions specialists.

Find Opiate Addiction Treatment Today

If you or a loved one is struggling with opioid addiction, know that you’re not alone and that there’s effective treatment available. At Moving Mountains Recovery, we offer multiple levels of care and personalized treatment plans, so we can meet you where you’re at and deliver the care you need to be successful in recovery.

An opioid addiction treatment program may include:

• A substance abuse and mental health evaluation
• Guided detox under medical supervision
• Behavioral therapies, such as dialectical behavior therapy (DBT) and motivational interviewing (MI)
• Holistic therapies such as art, yoga, and meditation
• Relapse prevention planning
• Drug tests to ensure compliance
• Medication-assisted treatment (MAT)

Our science based addiction treatment program is built on compassion, structure, and evidence-based support. Whether you’re starting your recovery journey for the first time or returning after a relapse, we’ll help you build the tools and confidence needed to move forward

To learn more about your opiate rehab options, the behavioral therapies we offer, or how to get started with addiction treatment, please reach out to Moving Mountains Recovery today. We’ll verify your insurance, assess your needs, and help you take the first steps toward recovery.

References:

1. National Institute of Health (NIH): Hydrocodone
2. NIH: Hydrocodone and Acetaminophen
3. U.S. Drug Enforcement Administration (DEA): Drug Scheduling
4. American Academy of Pediatrics: Hydrocodone and Acetaminophen
5. DEA: Hydrocodone
6. The Journal of Pharmacology and Experimental Therapeutics: Hydrocodone, Oxycodone, and Morphine Metabolism and Drug–Drug Interactions
7. U.S. Food and Drug Administration (FDA): Careful: Acetaminophen in pain relief medicines can cause liver damage
8. National Institute on Drug Abuse (NIDA): What is the scope of prescription drug misuse in the United States?
9. NIDA: Drug Overdose Deaths: Facts and Figures
10. Journal of Pain and Symptom Management: Buprenorphine: Considerations for Pain Management
11. American Psychiatric Association (APA): Opioid Use Disorder