Naltrexone is an opioid antagonist drug and is generically known as Naltrexone hydrochloride. It is administered by injection under the name Vivitrol, or by mouth under the name Revia, to help prevent alcohol or drug abuse relapse. In terms of drug abuse, it has been shown to be effective in blocking the physical dependence of morphine, heroin and other opioids. It works by binding with other opioids at receptor sites in the brain. When Naltrexone binds with other opioids, it sets up a resistance against them. Because of this action, it is effective in completely blockading the euphoric effects of the other drugs. For this reason, this drug is also useful in helping former opioid addicts to stay off drugs and it is beneficial in precipitating withdrawal symptoms of opioids.

In terms of alcohol abuse, Naltrexone has been proven to prevent the physical craving for alcohol and is widely used in the treatment of recovering alcoholics. It has also been shown to reduce the frequency and severity of an alcohol relapse. This medication helps reduce heavy drinking by people who continue to drink and has been able to help people return to normal drinking levels. In 2008, the National Institutes for Health conducted a study with Naltrexone. The study revealed that some alcoholics have a specific variant opioid receptor gene that strongly reacts to Naltrexone. The people with this variant gene were able to achieve success in cutting back or discontinuing their alcohol intake. This variant gene is commonly found in 60-70% of people of Asian descent, 30% of those with European descent and it is rarely present in Africans. Furthermore, multiple studies showed the drug, administered in addition to a psychotherapy recovery program, improved success rates, percentage of long-term abstinence from alcohol and the percent of relapsed patients.

Naltrexone Use and Side Effects

Naltrexone is easily and rapidly absorbed by the gastrointestinal tract after being taken orally. It will reach its peak level in the body within one hour after it has been ingested. The standard dosage for treatment of drug or alcohol dependence is one 50 mg. tablet taken once per day with or without food. This dosage can be increased to 150 mg per day depending on individual circumstances. When prescribed for the treatment of alcohol dependence, the drug will be administered intravenously as a time-released formulation taken once per month. Naltrexone should not be used in people on methadone or other opiates, as this can cause sudden withdrawal symptoms, physical injury, coma or death. Overuse of the drug can cause liver damage.

Before beginning treatment with Naltrexone, the health care provider will order tests to see if any opioid medicines or opioid street drugs were used in the last 10 days. The patient should tell the physician if they have or ever had depression, kidney disease, hepatitis, liver disease, hemophilia or any other bleeding disorder.

Minor side effects from taking Naltrexone include:

  • Irritability,
  • Nervousness,
  • Nausea,
  • Vomiting,
  • Dizziness,
  • Change in energy level,
  • Diarrhea,
  • Rash,
  • Loss of appetite,
  • Constipation,
  • Headache,
  • Muscle or joint pain
  • Difficulty falling or staying asleep.

More severe symptoms of Naltrexone can occur, though not common in most patients. These include:

  • Excessive fatigue,
  • Jaundice of the eyes or skin,
  • Dark urine,
  • Light-colored stool,
  • Pupil constriction,
  • Unusual bruising,
  • Unusual bleeding,
  • Pain in the upper right side of the stomach that subsists for more than a few days,
  • Anxiety,
  • Breathing problems,
  • Depression,
  • Suicidal thoughts or acts,
  • Extreme sadness and feelings of hopelessness, guilt, worthlessness, helplessness,
  • Confusion,
  • Hallucinations

Most patients tolerate Naltrexone well, with the most common side effect being nausea. It should be noted that Naltrexone may impair an individual’s reasoning skills and actions and caution should be taken when driving or using machinery.

Naltrexone Use for Withdrawal and Detox

Naltrexone is quite successful in the treatment of people addicted to heroin, morphine, oxycodone, opioids and alcohol. It reduces the rewarding effects of opioid drugs and alcohol use and the craving for it. Treatment has been most successful among patients who are motivated, and are part of an inpatient recovery program or live in a stable social situation. Before beginning treatment, the physician must determine if the patient is totally withdrawn from all opioids before using Naltrexone or it will bring on withdrawal symptoms. Toxicology and liver function of the patient should also be assessed before the use of Naltrexone. The drug has no abuse potential and the patient will not build up a tolerance to it. The efficiency of Naltrexone can be decreased if the patient is taking cold or cough medication, anti-diarrhea medication, opioid analgesics, nonsteroidal anti-inflammatory drugs, Thioridazine or Yohimbine. Healthcare providers should determine the length of treatment for each patient on an individual basis. Patients who have achieved abstinence may take Naltrexone on occasion, when they are stressed and at risk of a relapse during holidays, vacations and times of personal tragedy.

Multiple studies have been performed on the efficacy of Naltrexone, all showing superior results when tested against placebo. In one study of 104 patients who were addicted to alcohol, the drug showed a 51% rate of abstinence, compared to 23 % in those taking placebo, and a 31% percent chance in relapse, compared to 60% with placebo. With multiple studies confirming similar data, it is advised that Naltrexone, in conjunction with a professional treatment program that also offers counseling, behavior modification and/or lifestyle changes, affords the patient the greatest chance of recovery from drug or alcohol abuse.