Naltrexone Treatment for Opioid Addiction

Naltrexone Treatment for Opioid Addiction

Naltrexone Treatment for Opioid Addiction

Naltrexone Treatment for Opioid AddictionNaltrexone is a medication that doctors can prescribe as part of a larger treatment regimen for people recovering from active addictions to opioid (narcotic) drugs. It belongs to a group of substances called opioid receptor antagonists, and effectively blocks the mind-altering activity of legal medications such as oxycodone and hydrocodone, as well as illegal substances such as heroin and opium. Because of the abrupt manner in which naltrexone stops the effects of opioid drugs, doctors only issue prescriptions of the medication to people in recovery programs who have already gone through opioid withdrawal.

Background Information

Significant numbers of nerve cells in the brain, spinal cord, stomach and small intestine have sites on their surfaces called opioid receptors. When naturally occurring opioid-like chemicals in the body-including substances called endorphins, edomorphins and enkephalins-attach themselves to these receptors, they lower pain sensitivity in the nerve cells and produce a general sense of ease and well-being. Opioid drugs have shapes and chemical signatures that mimic or strongly resemble the shapes and signatures of the body’s natural opioids. This similarity grants them access to the opioid receptors; once molecules of these drugs attach themselves to the opioid receptors, they trigger the intense euphoria classically associated with opioid use/abuse. The process of opioid addiction begins when users of any given narcotic drug repeatedly seek to recreate the level of euphoria they feel when they first started drug use.

Naltrexone’s Effects

As an opioid receptor antagonist, naltrexone also gains access to the opioid receptors located in the brain and body. However, unlike opioid drugs, which activate those receptors and trigger euphoria, naltrexone occupies the receptor sites without activating them. When opioid drugs try to access the opioid receptors, naltrexone essentially blocks them and prevents them from producing their normal euphoric effects. For reasons that doctors and researchers don’t fully understand, naltrexone’s actions in the body also reduce the intense cravings that alcoholics commonly feel when they enter recovery and stop drinking.

Timing of Use

When naltrexone enters the body, it quickly starts occupying the opioid receptors and denying access to opioid drugs. In people still using opioids, this rapid reduction in drug availability can produce unusually strong versions of common opioid withdrawal symptoms such as muscle pain, abdominal cramping, anxiety, nausea, vomiting, and mental agitation. In order to avoid triggering severe withdrawal in their patients, doctors only prescribe naltrexone to recovering addicts who have stopped all opioid use and are a week to 10 days past the withdrawal period, the Substance Abuse and Mental Health Services Administration explains.


Naltrexone is available by prescription in the US as a generic medication and under the brand names ReVia and Depade. It comes in forms that include tablets and an extended-release solution that’s injected directly into muscle tissue. Specific doses of the medication vary from person to person in accordance with a doctor’s assessment. However, common treatment doses for naltrexone tablets begin at 25 mg per day, and may eventually increase to 50 mg per day. People taking extended-release naltrexone typically receive a monthly injection of roughly 350 to 400 mg.

Side Effects

Naltrexone use can lead to the onset of a variety of relatively common and relatively rare side effects. Potential side effects that occur with some frequency include nausea, vomiting, headaches, muscle pain, joint pain, unusual fatigue, restlessness, insomnia, anxiety, and mild cramping in the stomach or general abdominal area. Side effects that occur less frequently include an accelerated heartbeat, dizziness, irritability, unusually intense thirst, diarrhea, constipation, loss of normal appetite, chills, male sexual dysfunction, and cold-like symptoms in the nose, throat, and/or sinuses.

Generally speaking, the side effects listed above are not serious enough to require medical attention. However, naltrexone use can also lead to more serious side effects that do require attention. These effects can include fever, chest pain, a confused mental state, severe stomach or abdominal pain, excessive urination, uncomfortable urination, generalized body itching, hallucinations, depression, large mood swings, shortness of breath, blurry vision, aching or swelling in the eye region, unexplained weight gain, ear ringing, and swelling that appears in the feet, calves or face. People who take large doses of naltrexone also sometimes develop liver damage, which can produce symptoms such as darkened urine, easy bruising or bleeding, jaundice, unusually pale stools, extreme fatigue and persistent pain in the area of the liver (upper-right abdomen).


People who take unusually large doses of opioids can potentially overcome naltrexone’s blocking effect on the opioid receptors and get “high.” However, this level of opioid use also typically triggers serious or severe allergic reactions within the body. In order to avoid the complications associated with this chain of events, doctors usually only prescribe naltrexone to recovering addicts who have well-established treatment plans and demonstrate an ability and willingness to stick to those plans.

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