What Happens If You Take Naltrexone With Opioids Still In Your System?

Naltrexone, also known as Vivitrol, is a medication for opioid addiction that can be taken after a person has fully detoxed from opioids, or at least seven to 10 days after last opioid use.

Taking naltrexone with opioids still in your system could precipitate, or unexpectedly cause, opioid withdrawal symptoms due to its blockade effect on opioid receptors in the body.

Learn more about how Naltrexone interacts with other drugs

Effects Of Taking Naltrexone After Recent Opioid Use

Naltrexone is an opioid antagonist, which means it can block the sedative and euphoric effects of opioids such as heroin, oxycodone, morphine, and fentanyl.

Unlike medications such as methadone or buprenorphine (Suboxone), which are also used to treat opioid addiction, naltrexone is not given until a person has fully detoxed.

Taking naltrexone with opioids in your system could cause symptoms of acute opioid withdrawal.

Opioid withdrawal symptoms may include:

• anxiety
• agitation
• nausea and vomiting
• stomach pain
• muscle and bone pain
• headache
• diarrhea
• chills

Symptoms of opioid withdrawal can be mild to severe in nature. This can be most effectively treated within an inpatient setting, such as a detox center or drug rehab center.

How Long After Detoxing From Opioids Can You Take Naltrexone?

Naltrexone may be taken seven to 10 days after one’s last use of a short-acting opioid (e.g. heroin), or up to 20 days after last use of a long-acting opioid such as methadone.

Adhering to this waiting period allows for your body to fully eliminate opioids from your system, through a process commonly known as detoxification or detox.

What Happens If You Take Opioids While On Naltrexone?

Using opioids while on naltrexone is not advised. While naltrexone can block the effects of opioids, it can’t prevent an overdose. In fact, it could make it more likely.

Because naltrexone blocks the effects of opioids, an individual who takes a high dose may not be aware that they’ve taken a dose high enough to overdose, due to naltrexone’s blockade effect.

This is particularly dangerous for people who have recently detoxed. After detox, your tolerance for opioids goes down, which reduces your body’s ability to handle high doses of opioids.

How To Start Naltrexone Treatment For Opioid Dependence

Naltrexone is a medication that’s FDA-approved to treat opioid use disorder, in conjunction with behavioral therapy and other support services.

Naltrexone can be administered in the form of a monthly injection (Vivitrol), or be taken orally in pill form.

Any healthcare provider who is licensed to prescribe medications can prescribe naltrexone for opioid addiction. By calling our helpline, we can help you find a treatment provider near you.

Find Naltrexone Treatment For Opioid Addiction

Opioid use disorder affects over two million adults in the United States. With substance use treatment and a strong support system, recovering from addiction is possible.

Browse our directory or reach out to the Substance Abuse and Mental Health Services Administration (SAMHSA) for more information about addiction recovery.

Written by the Addiction Resource Editorial Staff