Do not take this medicine if you are allergic to naltrexone, or if you have:

• an addiction to narcotics;

• a history of alcohol or narcotic drug use within the past 7-10 days; or

• drug or alcohol withdrawal symptoms.

Before taking naltrexone, tell your doctor if you are allergic to any drugs, or if you have:

• kidney disease;

• liver disease; or

• a bleeding disorder such as hemophilia (if you are using naltrexone oral injection).

If you have any of these conditions, you may need a dose adjustment or special tests to safely take this medication.

FDA pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Naltrexone oral can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.

Do not use narcotic drugs or alcohol while taking naltrexone oral. Never try to overcome the effects of the medication by taking large doses of narcotic drugs or alcohol. Doing so could result in dangerous effects, including coma and death.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using naltrexone oral and call your doctor at once if you have any of these serious side effects:

• blurred vision or eye problems;

• fast heartbeat;

• mood changes, hallucinations (seeing or hearing things), confusion, thoughts of hurting yourself;

• nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);

• ear pain, ringing in your ears;

• skin rash or itching; or

• wheezing, difficulty breathing.

Less serious side effects may include:

• feeling anxious, nervous, restless, or irritable;

• feeling light-headed, fainting;

• increased thirst;

• muscle or joint aches;

• weakness or tiredness;

• sleep problems (insomnia); or

• decreased sex drive, impotence, or difficulty having an orgasm.