All You Need to Know About the M366 Pill.


When patients have chronic pain or cough, doctors sometimes prescribe M366 pill to help them deal with the pain. However, it is important to note that this pill is a prescription drug and is only available to the public, legally, if they have a doctor’s prescription.

M366 acetaminophen/hydrocodone pill is a white, elliptical pill that contains 325 mg and 7.5 mg of acetaminophen and hydrocodone bitartrate, respectively. It is used to deal with back pain, cough, or general body pain that seems not to be affected by generic pain killers. It is a schedule 2 controlled substance and should not be transferred from one user to another.

In this article, we will discuss the identification of the M366 pill, how it works, its safety for the different classes of people – including pregnant women and older people. We will also consider how safe it is to use the M366 pill with other medications.

Understanding the M366 Pill

The M366 pill is a combination of a narcotic and an analgesic, hence its drug class being narcotic analgesic, or opioid analgesic. It contains the two types of drugs in different ratios and exerts its influence on the central nervous system to stop the feeling of pain. It contains 325 mg of acetaminophen (analgesic)and 7 mg of hydrocodone bitartrate (narcotic) in one pill.

M366 Pill (acetaminophen and hydrocodone)
M366 Pill (acetaminophen and hydrocodone)

The pill is white and comes in an oval or elliptical shape that is mostly smooth. On the face of the pill, the imprint, “M366” is prominent while its other side is blank. It has not indentation on its surface as can be seen in some other narcotic analgesic such as the yellow T259 pill.

The M366 pill is a prescription drug that used to be allowed for any type of pain. However, due to the drug misuse cases in the United States of America and the dependence of many users on the drug, it is now restricted to the treatment of severe and chronic back pain and cough. It is meant for a short-term use as can be experienced in association to a medical condition or intense pain after surgery, and due to its tendency to cause dependence and addiction.

The authentic M366 pill is supplied by Mallinckrodt Pharmaceuticals; although other suppliers such as Altura Pharmaceuticals Inc., and Nucare Pharmaceuticals Inc., used to be repackagers of a similar pill, their brands have been discontinued.

How the M366 Pills work

Like every analgesic, M366 pills aims to reduce the amount of pain an individual feel when they are used. However, unlike most analgesic, it does not target the site of pain, but the central nervous system, the brain and spinal cord to be precise. It works by using a dual mechanism action.

When a pill of M366 gets into the system, it binds to the opioid receptors – they are most abundant in the brain and spinal cord but also present in the lungs and stomach – that are responsible for sensing pain and controlling addiction. This attachment to the opioid receptors reduces the feeling of pain the individual receives from its brain and increases the feeling of pleasure at the same time. This action is carried out by the narcotic in the M366 pill. The acetaminophen in the pill acts by inhibiting the production of prostaglandins by stopping the stopping the action of the cyclo-oxygenase enzymes responsible for their production.

With the narcotic and analgesic combination, the inflammation of the pain site, fever that may be associated with the pain or condition, and the pain, become deadened. However, despite their effectiveness, they can cause dependence, which results in increased dosages for their users.

Side Effects of the M366 Pills

Like every medication known to man, there are side effects attached to the use of M366 pill. Some of these side effects are extremely rare and require immediate medical attention while others are relatively common. The common ones include:

  • Dizziness
  • Vomiting
  • Sore throat
  • Headache

More serious side effects include:

  • Fast heartbeat
  • Agitation
  • Bluish skin or lips
  • Bleeding gums
  • Choking
  • Dark and reduced urine volume
  • Blood in vomit, urine, or stools

If you feel any of these side effects or symptoms, contact your doctor immediately.

Drugs Interaction with M366 Pill

Being a drug that exerts its effect on the central nervous system, it is important that you know what drugs are unsafe to use with M366 pill. Some of these medications have a mild interaction with M366, while others can have serious interactions that may lead to medical emergencies.

Mild interaction drugs include:

  • Benadryl (diphenhydramine)
  • Cymbalta (dulotexine)
  • Metoprolol Succinate ER
  • Zyrtec (cetirizine)

Serious interaction drugs include:

  • Xanax (alprazolam)
  • Tylenol (acetaminophen)
  • Lyrica (pregabalin)
  • Flexeril (cyclobenzaprine)

These medications have influence on the central nervous system and lungs; therefore, using them in combination with M366 pills can prove to be fatal as their effect in more pronounced. Ensure that your doctor is informed about all your medications before you get a M366 pill prescription.

Who is M366 pill safe for?

M366 pill is made for people who suffer from chronic and severe back pain, due to its effect on the spinal cord, and people ho have cough, due to its effect on the lungs. However, not everyone with these conditions can use M366. Some of those that may not get a prescription of M366 include:

Asthmatic patients

It is highly dangerous for patients who struggle with asthma and other respiratory conditions to use M366 pill. It exerts some of its effects on the lungs, which may seem like an advantage to them, but can also cause deterioration in the condition of the lungs as the opioid receptors get dependent on the medication and need increased dosages as time goes by.

The lungs may begin to inflame, causing breathing problems, and with one of its side effects being breathing problems, they are better off without it.

Pregnant women

Although there is no concrete evidence against its safety for pregnant women, the presence of narcotic in the drug suggests that it is unsafe for the fetus. There are cases of fetuses that have become addicted to narcotics in the womb and experience severe withdrawal symptoms after they are born.

Individuals with Drug abuse issues

People who have an history of substance abuse are not permitted to use this medication largely due to the presence of narcotics in it. These individuals may relapse and become heavily dependent on the medication.


M366 pill is a narcotic analgesic that is available only on prescription due to its tendency to cause dependence and addiction. The white, oval pill is supplied by Mallinckrondt Inc and is considered unsafe when combined with certain drugs, such as Xanax.

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Ayomide is a fiction and non-fiction writer. A lover of science and everything mysterious that surrounds it, he seeks out new information to keep his interest alive.

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