Naltrexone (Vivitrol)

Naltrexone is the generic form of the brand-name drug Vivitrol, which is used to prevent substance abuse in people who have been addicted to alcohol or opioid pain medications.

Examples of opioid painkillers include Norco (hydrocodone/acetaminophen), OxyContin (oxycodone), and codeine.

Some forms of this medicine may also help those who suffer from tobacco addiction, certain developmental disorders (such as autism), or other impulse control disorders (such as gambling).

Naltrexone is only one part of a complete treatment program for addiction that should also include lifestyle changes, counseling, and support.

Additionally, low doses of naltrexone have been shown to reduce symptom severity in fibromyalgia, Crohn’s disease, multiple sclerosis, complex regional pain syndrome, and other chronic pain disorders. At present, these are off-label uses.

The drug is in a class of medicines known as opiate antagonists. It works by blocking the effects of narcotic drugs. It's available as a tablet and an injection.

The Food and Drug Administration (FDA) approved naltrexone in 2010.

Low-Dose Naltrexone (LDN)

Low doses of naltrexone have been shown to reduce symptom severity in multiple sclerosis, fibromyalgia, Crohn’s disease, complex regional pain syndrome, and other chronic pain disorders.

At present, these are off-label uses.

Ask your doctor if low-dose naltrexone (LDN) is an option if you have been diagnosed with any of these conditions.

Naltrexone and Weight Loss

A sustained-release formulation of naltrexone has been combined with a sustained-release formulation of the bupropion (Contrave) for weight loss in people who have been diagnosed with obesity.

The FDA has not approved the combined form of naltrexone/burpropion for this use, due to concerns regarding cardiovascular-related side effects.

However, naltrexone alone has been prescribed off-label for weight loss. If you are obese or overweight, ask your doctor if naltrexone is an option for you.

Naltrexone Implants

Although primarily an oral drug taken in pill form, naltrexone implants, which are inserted into the lower abdominal wall under local anesthetic, have been used to treat opioid addiction and/or abuse/misuse.

Implants release a controlled amount of naltrexone into the body and are effective for three to six months.

Naltrexone implants block the effects of opiate drugs.

At present, naltrexone implants are not approved by FDA, and are only available in clinical settings offering 24-hour monitoring and supervision, such as drug and alcohol rehabilitation facilities.

Naltrexone Warnings

Naltrexone can cause liver damage when taken in doses larger than what is recommended.

Tell your doctor immediately if you experience any of the following symptoms:

• Pain in the upper right part of the stomach that lasts more than a few days
• Yellowing of the skin or eyes (jaundice)
• Excessive fatigue
• Unusual bleeding or bruising
• Loss of appetite
• Dark urine
• Light-colored bowel movements

Naltrexone shouldn't be used by people who are still using opioids or drinking large amounts of alcohol.

If you take naltrexone with high doses of opioid drugs, it may cause serious injury, coma, or death.

Your healthcare provider may order tests to determine if you've taken any opioid medicines or used any opioid street drugs in the past seven to 10 days before recommending naltrexone.

If you took opioids before naltrexone, you may be more sensitive to the effects of these painkillers when you finish treatment.

The medicine will help you avoid drugs and alcohol, but it won't prevent or relieve withdrawal symptoms. It may even worsen them.

You shouldn't take naltrexone if you have recently stopped using opioid drugs and are currently experiencing withdrawal symptoms.

Before taking naltrexone, you should tell your doctor if you have or have ever had:

• Hepatitis
• Liver disease
• Depression
• Kidney disease
• A bleeding disorder such as hemophilia

People who abuse drugs or alcohol often suffer from depression and may try to harm themselves. Naltrexone won't decrease this risk.

You should tell your doctor if you experience any of the following symptoms:

• Suicidal thoughts or actions
• Extreme sadness
• Anxiousness
• Hopelessness
• Guilt
• Worthlessness
• Helplessness
• Anhedonia (inability to find pleasure in anything)

Tell your physician you are taking naltrexone before having any type of surgery, including dental procedures.

If you're taking the injectable form of this drug, you may notice pain, swelling, redness, bruising, or a hard lump at the injection site. Call your doctor if you experience these symptoms.

Continue to take naltrexone even if you feel well. Don't stop taking this medication without first talking with your physician.

In case of a medical emergency, you may want to wear a medical alert tag or carry an ID card that states you are taking naltrexone, so your health care team is aware.

The medication is only effective if it's used as part of an addiction treatment program. You should attend all counseling sessions, support group meetings, or other treatment programs recommended by your doctor.

Pregnancy and Naltrexone

Naltrexone might harm an unborn baby. You should talk to your doctor about using this medicine if you are pregnant or planning to become pregnant.

It's also unknown whether naltrexone could harm a breastfeeding infant. Talk to your doctor before breastfeeding while taking this medication.

Common Side Effects of Naltrexone

You should tell your doctor if any of the following side effects become severe or don't go away:

• Nausea, vomiting, diarrhea, or constipation
• Stomach pain or cramping
• Loss of appetite
• Headache
• Dizziness
• Nervousness, irritability, or anxiety
• Tearfulness
• Increased or decreased energy
• Difficulty falling asleep or staying asleep
• Drowsiness
• Rash
• Muscle or joint pain
• Mild discomfort at injection site (injectable form)

Serious Side Effects of Naltrexone

You should call your doctor immediately if you experience any of the symptoms listed in the warning section or any of the following serious side effects:

• Signs of an allergic reaction (rash; hives; itching; breathing difficulties; chest tightness; or swelling of the mouth, face, lips, or tongue)
• Hallucinations
• Confusion
• Blurred vision or eye problems
• Cough, wheezing, or breathing troubles
• Severe vomiting or diarrhea

Naltrexone comes as a tablet or as an injection.

When taken for fibromyalgia and other off-label uses, a once-daily dose of 4.5 mg is typical.

Oral Naltrexone: If it's taken at home, the drug is usually taken once a day with or without food.

If it's taken at a treatment center, naltrexone can be administered once a day, once every other day, once every third day, or once every day.

The typical dose of naltrexone is 50 milligrams (mg) a day. If it's given in a clinic setting, your health care provider may put you on a higher dose (up to 150 mg) to be taken on different days.

You can take this medicine with or without food.

Take naltrexone exactly as prescribed. You shouldn't take more or less of the drug than is recommended.

Injectable Naltrexone: The injection of naltrexone is typically given once a month by a doctor or nurse in a clinic setting.

You should receive your injections regularly to get the most benefit.

Naltrexone Overdose

If you suspect an overdose, contact a poison control center or emergency room immediately.

You can get in touch with a poison control center at (800) 222-1222.

Missed Dose of Naltrexone

If you miss a dose of oral naltrexone, take it as soon as you remember.

However, if it's almost time for your next dose, skip the missed dose and continue on your regular dosing schedule.

If you miss an injection of naltrexone, contact your healthcare provider.