What Are Opioid Blockers?

What are Opioid Blockers

Opioid Antagonists are types of medications that essentially block the effects of opioid agonist medications/drugs (heroin, heroin, oxycodone, methadone, hydrocodone, morphine, opium). Drugs like heroin and prescription painkillers attach to the opioid receptors in the brain and cause full release of dopamine. This makes the user feel “high.”

Opioid Agonists Vs. Opioid Antagonists

On the other side of the spectrum, opioid blockers (opioid antagonists) also bind to the opioid receptors in the brain, but they do not activate the receptor and do not cause the release of dopamine – there is no “high associated with it.” Once the antagonist is in-place on the receptor, it becomes a true opioid blocker by blocking any agonists from binding to the receptor. This means that heroin, oxycodone, methadone, hydrocodone, morphine, opium and other drugs won’t get you high, and will be blocked from the receptors by the opioid blocker.

Additionally, opioid antagonists can also “knock” opioid agonists off the receptors and then block them from reattaching to the receptors. This is the case with opioid reversal drugs like Narcan, that – in the event of an opioid overdose – knocks the opioid agonists causing the overdose off the receptors, essentially reversing the effects of the opioids and the overdose.

How Naltrexone and Naloxone Work:

Opioid Receptor Unblocked Free of Opioids

Unblocked Opioid Receptors & No Opioids Present

In a normal, unmedicated & sober individual, opioid receptors are open. 

Unblocked Opioid Receptors & Opioids Are Present

When an individual uses opioids, like prescription narcotic drugs or heroin, the opioids in the drugs bind to opioid receptors in the brain. This causes the side effects of heroin and other opioids.

Opioid Receptor Unblocked Heroin Present
Heroin Overdose

Heroin Overdose & Opioid Receptors

If an individual uses too much heroin or other opioid drugs, the receptors become flooded with opioids and the sedative effects of the drug are too strong. Risk of respiratory depression and death are high.

Heroin Overdose & Naloxone Administered

When an opioid antagonist like Naloxone is administered to someone suffering from an opioid or heroin overdose, the Naloxone “knocks” the heroin/opioid off the receptor, and takes its place.

Heroin Overdose Naloxone Administered
Opioid Receptor Fully Blocked Free of Opioids

Opioid Receptors Blocked

Now binding to the receptor, Naloxone becomes a temporary opioid blocker. It does not allow the heroin/opioids — which are still in a person’s system — to attach to the receptors. But remember, this is only temporary, and an individual should seek medical attention after being administered Naloxone or Narcan.

Using Opioid Blockers for Substance Abuse Treatment

Heroin overdose reversal drugs like Narcan can be used to save lives in the event of an overdose, but other forms of opioid antagonists, partial agonists and opioid blockers can be utilized in treatment of addiction and relapse prevention. Risks and benefits of such treatments should be weighed carefully.

Opioid Receptor Blocking Heroin
Opioid Receptor Unblocked Free of Opioids

Remember, The Long Term Goal is to Get Off Medications

Remember that the ultimate goal of getting sober is to get completely sober. Medications can help you to get there, but you ultimately want to be back to a normal balance in the brain again. 

What Is Narcan?

Narcan is a form of Naloxone nasal spray that can reverse the effects of opioids during an overdose. It is easy to use and considered a life-saving tool, that is given to first responders and kept in public spaces such as libraries, in hopes of preventing deaths from opioid overdoses. It is highly recommended that you should have Narcan if you live with an opioid user.

Is Narcan the Same as Naloxone?

Narcan’s active ingredient is Naloxone Hydrochloride. Naloxone is the opioid antagonist that can both reverse the effects of opioid overdose and block opioids from binding with the opioid receptors.

Do You Have To Go To The Hospital After Using Narcan or Naloxone?

Yes, you should seek medical attention after using Narcan or Naloxone to reverse the effects of opioids after an overdose. It is important to remember that you are not out of the woods just yet. Naloxone has a very short half-life, meaning it wears off after about 30 minutes to 1 hour. If you do not seek medical attention immediately, and you have taken a high dose of opioids, the risk of overdose occurring again is high.

Additionally, a person may go into immediate opioid withdrawals after being administered an opioid blocker. If the individual’s opioid dependency is strong enough, acute withdrawal symptoms can cause a medical emergency as well.

What is Evzio?

Evzio is an auto-injector device that is used to inject Naloxone into an opioid overdose victim. Giving an intramuscular injection into the thigh, Evzio can immediately reverse the effects of opioids. The device is easy to use and even gives the user instructions on the next steps to take after an opioid overdose.

Like Narcan, the active ingredient of Evzio is Naloxone. The method the naloxone is administered is differentl – intramuscular injection versus nasal spray – but the medicine works in the same way.

What is Naltrexone?

Naltrexone is an opioid blocker, similar to Evzio and Narcan, but with a much longer half-life. This means that it blocks opioids for a much longer than the 30-60 minutes that Naloxone remains active. Naltrexone is not to be used to reverse overdoses, rather Naltrexone is used to prevent overdoses.

Naltrexone comes in a pill form and can also be administered intravenously. The brand name for oral Naltrexone (Naltrexone Pills) in the United States is Revia.

How Long Does Naltrexone Block Opioids For?

Naltrexone can block the effects of opioids like heroin, oxycontin, and other prescription opioids for 24-48 hours, depending on the dosage and delivery method. Naltrexone can precipitate withdrawal symptoms (it can cause you to go into opioid withdrawal) if you have an opioid addiction and/or use Naltrexone in combination with heroin or other opioids.

What is Vivitrol?

Similar to Evzio and Narcan, Vivitrol is also an opioid blocker, but is used primarily to prevent relapse of opioid addiction. Vivitrol acts as a layer of accountability and encourages an addict to stay sober. If the addict does use opioids like heroin or painkillers, the vivitrol will block the effects and the addict will not get high.

Removing the “pleasure” from the use of the drugs is designed to dissuade the user from using drugs and further. Since Vivitrol is an opioid blocker, it also comes with the added benefit of offering protection against an overdose – should the user relapse and take too many opioids. This is especially helpful because addicts who relapse often misjudge their tolerance and take too much of the drug – whether it be heroin, opioid pills, or other forms of opioids.

How Medication Assisted Treatment is Being Used to Treat Serious Addictions

Medication Assisted Treatment for opioid addiction is an evidence-based treatment model for addiction that sees very good long-term success rates. Not only have studies shown MAT to help prevent heroin relapse in even the most severe addictions but utilizing opioid blocking medications has helped to save lives from overdoses in the wake of an opioid crisis in the United States.

Families who have struggled with opioid addiction should educate themselves further on Narcan, Evzio, Naltrexone, Naloxone, and Vivitrol and how these medications can help your loved one back on the road to recovery or save them when they stumble.

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Mike Loverde

As a Certified Intervention Professional (CIP), member of NAATP, NAADAC, and accredited by the Pennsylvania Certification Board, Mike Loverde knows first-hand what it’s like to live life with addiction. By overcoming it, he had a calling to work with others who struggle with drug and alcohol addictions—the people who use and the families who feel helpless watching them decay.

With thousands of interventions across the United States done and many more to come, Loverde continues to own the intervention space, since 2005, by working with medical doctors, psychiatrists, psychologists and others who need expert assistance for their patients who need intervention. To further his impact on behavioral health and maximize intervention effectiveness, Loverde is near completion of a Masters in Addiction Studies (MHS) accreditation, as well as a Licensed Independent Substance Abuse Counselor (LISAC), and is committed to attaining the designation of a Licensed Professional Counselor (LPC).

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