Naltrexone is used to control cravings for opioid drugs. It does not address issues with withdrawal.
Naltrexone Vs. Naloxone
Naltrexone is an opioid antagonist medication. It is used to treat individuals struggling with opioid use disorder, alcohol use disorder, and other substance use disorders.
Brand names for naltrexone include ReVia and Vivitrol, among others.
Naltrexone should not be confused with another opioid antagonist, naloxone. Narcan is a common brand name for naloxone.
Naloxone is a medication used to treat overdose for an opioid drug. If it is administered quickly enough, it occupies the neuroreceptors in the brain and spinal cord that are normally occupied by opioid drugs, removing the drugs and reversing the effects of the overdose.
It is not directly used in the treatment of opioid addiction.
Naloxone is also included in some medications that are used to treat opioid abuse, such as Suboxone (buprenorphine and naloxone), but its presence in these medications is designed to protect the drug from abuse.
Naltrexone is used directly for the treatment of substance use disorders.
What Does Naltrexone Do?
Naltrexone is considered to be an opioid antagonist. This means it attaches to the neurons in the brain called endogenous opioid receptors and blocks the effects of substances that would normally attach to the receptor sites.
The effects of naltrexone are not completely understood. However, it has been suggested that it reduces many of the effects of opioids, including cravings for the drugs, because it occupies the same receptor sites that opioids occupy.
It may also reduce the effects associated with taking opioids, such as feelings of euphoria, respiratory suppression, and others.
Research has indicated that naltrexone is effective in reducing cravings for other drugs, particularly for alcohol. The FDA approved naltrexone as a treatment for alcohol use disorders and opioid addiction.
Other research suggests it may be useful in controlling urges of different types of addictions, including behavioral addictions like internet addiction.
Effects and Side Effects of Naltrexone
Naltrexone is most often used for individuals in recovery from a substance use disorder.
Using naltrexone does not produce any level of euphoria. In fact, it may reduce the sensations of euphoria that occur with the use of other drugs.
It may also reduce drug and alcohol use among individuals who relapse during their recovery by reducing the psychoactive effects of these drugs.
Naltrexone is typically designed to be taken once a day, most often in the morning. The injectable form of naltrexone (Vivitrol) is longer-lasting, with its effects lasting up to 30 days.
Like all medications, naltrexone could cause side effects. Some of the most common side effects that individuals may experience from naltrexone will include:
- Gastrointestinal issues, such as nausea, constipation or diarrhea, and sometimes vomiting
- Irritability, jitteriness, restlessness, or anxiety
- Lethargy, sleepiness, or even mild insomnia
- Dizziness and muscle aches
- A mild rash or pain at the site where the drug is injected
In rare cases, individuals may experience an allergic reaction, such as an extreme rash, hives, swelling of the lips or fingers, anxiety, or panic attacks. In these cases, the medication should be discontinued, and the individual should contact their physician immediately.
Naltrexone in the Treatment of Opioid Abuse
Medications that are used in the treatment of substance use disorders, such as naltrexone, are not designed to be first-line treatments for the substance use disorder. That’s because some of these medications can address withdrawal symptoms, but they do not address the syndrome of substance abuse.
There is evidence that naltrexone may be effective in reducing cravings for opioids, alcohol, and perhaps some other drugs of abuse. However, such medications should not be the only intervention used in the treatment of a substance abuse issue or behavioral addiction.
Limitations of Naltrexone
Research indicates that naltrexone is not effective if the individual is not involved in a substance use disorder recovery program that includes counseling, peer support such as 12-step group participation, and other interventions. While naltrexone is an adjunctive treatment, which means it is an addition to a holistic recovery program, it is not designed to be the only intervention.
Naltrexone is optimally effective when the person has already been abstinent from drug use for one to two weeks. Its effectiveness significantly decreases if the person is actively using drugs.
Although naltrexone may assist an individual in steadily decreasing their use of drugs, it will not assist them in totally discontinuing use. Because it has no effect on withdrawal symptoms other than reducing cravings, it should not be taken to deal with withdrawal symptoms.
Useful but Underused
The research investigating the use of naltrexone is generally positive. In fact, its use appears to be even more effective in treating cravings for alcohol than for opioids.
Cravings are subjective experiences, and long-term opioid users may experience different emotional issues when dealing with cravings during recovery. For instance, alcohol is typically used orally, whereas many opioid drugs are snorted, smoked, or injected, resulting in much more efficient delivery to the brain. This produces higher levels of tolerance and is associated with a quicker onset of withdrawal symptoms 
when these drugs are discontinued.
Nonetheless, naltrexone is a useful medication that can assist in the recovery of opioid use disorder. It may help to address cravings and reduce the use of opioids.
Still, research studies have indicated that the number of prescriptions written for medications designed to deal with addictive behaviors is far lower than the prescriptions for opioid drugs. It appears that the number of physicians who are approved to prescribe opioid pain medications is over 20 times greater than the number of physicians who are authorized to write prescriptions for anti-addiction medications.
Research studies also indicate that less than half of individuals who are diagnosed with opioid use disorders have access to medications like naltrexone that can assist them.
While the research indicates that naltrexone can be extremely effective in helping an individual in recovery, it is most likely highly underutilized.
Can Someone Use Naltrexone Without Medical Supervision?
Although naltrexone is not listed as a controlled substance and not believed to have a significant potential for abuse, it does require a prescription from a physician to be obtained legally. This is because the drug has the potential for serious side effects, including allergic reactions in some individuals.
For this reason, individuals should not obtain or use naltrexone without being under the supervision of a physician.
Naltrexone should always be used according to its prescribed instructions. If an individual begins to experience serious side effects, they should contact their physician immediately.
How Should Naltrexone Be Used For Opioid Abuse?
Naltrexone can be a useful part of a recovery program for individuals with opioid use disorders or other substance use disorders.
Whether or not a person should be placed on naltrexone is determined first by a team of addiction treatment professionals. These professionals conduct a thorough assessment of the individual’s needs and then work with the person to develop a treatment plan. During this time, the potential use of the medication is discussed with the individual, empowering them to make an informed decision regarding the use of the drug.
While medications like naltrexone can be effective, naltrexone should only be used under the supervision of a physician and in combination with other components of a successful recovery program.
For more information on steps to recovery, take a look at the National Institute on Drug Abuse’s guide to a successful treatment recovery program.
