This medication is used to prevent people who have been addicted to certain drugs (opiates) from taking them again. It is used as part of a complete treatment program for drug abuse (such as compliance monitoring, counseling, behavioral contract, lifestyle changes). This medication must not be used in people currently taking opiates, including methadone. Doing so can cause sudden withdrawal symptoms.

Naltrexone belongs to a class of drugs known as opiate antagonists. It works in the brain to prevent opiate effects (such as feelings of well-being, pain relief). It also decreases the desire to take opiates.

Ask your doctor or pharmacist if you should have naloxone available to treat opioid overdose. Teach your family or household members about the signs of an opioid overdose and how to treat it.

This medication is also used to treat alcohol abuse. It can help people drink less alcohol or stop drinking altogether. It also decreases the desire to drink alcohol when used with a treatment program that includes counseling, support, and lifestyle changes.

Take this medication by mouth with or without food as directed by your doctor, usually once daily. This medication may be given as part of a program where a health care professional will watch you take the medication. In this case, this medication may be taken every 2 to 3 days to make it easier to schedule clinic visits. Naltrexone may be taken with food or antacids if stomach upset occurs.

A urine test should be done to check for recent opiate drug use. Your doctor may give you another medication (naloxone challenge test) to check for opiate use. Do not use any opiates for at least 7 days before starting naltrexone. You may need to stop certain opiate drugs (such as methadone) 10 to 14 days before starting naltrexone.

The dosage is based on your medical condition and response to treatment. Your doctor may start you at a lower dose and monitor you for any side effects or withdrawal symptoms before increasing your dose. Take this medication as directed. Do not increase your dose, take it more often, or stop taking it without your doctor's approval.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day.

Tell your doctor if you start using drugs (opiates) or alcohol again.

Nausea, headache, dizziness, anxiety, tiredness, and trouble sleeping may occur. In a small number of people, mild opiate withdrawal symptoms may occur, including abdominal cramps, restlessness, bone/joint pain, muscle aches, and runny nose. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Sudden opiate withdrawal symptoms can occur within minutes after taking naltrexone. Tell your doctor right away if any withdrawal symptoms occur, including:

• abdominal cramps
• nausea/vomiting
• diarrhea
• joint/bone/muscle aches
• mental/mood changes (such as anxiety, confusion, extreme sleepiness, visual hallucinations)
• runny nose

Naltrexone has rarely caused serious liver disease. The risk is increased when larger doses are used. Discuss the risks and benefits with your doctor. Tell your doctor right away if you develop symptoms of liver disease, including:

• nausea/vomiting that doesn't stop
• severe stomach/abdominal pain
• dark urine
• yellowing eyes/skin

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking naltrexone, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• current or recent use (in the last 7 to 14 days) of any type of opioid drug (such as morphine, methadone, buprenorphine)
• kidney disease
• liver disease

You should carry or wear medical identification stating that you are taking this drug so that appropriate treatment can be given in a medical emergency.

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Avoid alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

After stopping naltrexone treatment, you may be more sensitive to lower doses of opioids, increasing your risk of possibly life-threatening side effects from the opioid (such as decreased breathing, loss of consciousness).

This medication blocks the effects of opiate drugs (including heroin) and similar drugs (opioids). However, large doses of heroin or opioids can overcome this block. Trying to overcome this block is very dangerous and may cause serious injury, loss of consciousness, and death. Make sure you completely understand and accept the risks and benefits of using this medication. Follow your doctor's instructions closely.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This drug passes into breast milk. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include:

• dextromethorphan
• diarrhea medication (such as diphenoxylate)
• disulfiram
• opioid pain or cough relievers (such as codeine, hydrocodone)
• thioridazine

This medication may interfere with certain lab tests (such as drug tests), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

Lab and/or medical tests (such as liver function) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.