Naltrexone might not be right for you if you have certain medical conditions or take certain medication, including:

• Current or recent use of opioids or opioid-containing medications.
• Severe liver or kidney disease.
• Pregnancy or breastfeeding.
• History of depression or suicidality.
• Known allergy to naltrexone or any of its components.

Nausea, Dizziness, Vomiting, Stomach cramps, Abdominal pain, Headaches, Trouble sleeping, Fatigue, Nervousness or anxiety, Joint and muscle pain

When starting Naltrexone, you may experience mild to moderate levels of the listed side effects during the first 3 to 5 days. These typically diminish on their own as your body adjusts to the medication, usually by the fifth day.

If you are on thyroid medication, you may need to monitor your thyroid levels more closely as you start Naltrexone. IF you develop symptoms of hyperthyroidism while taking Naltrexone, such as heart racing, increased anxiety, restlessness, or trouble sleeping, please stop Naltrexone and talk to the prescriber for your thyroid medication.

Note: You MUST stop taking Naltrexone at least 48 hours before any surgical or diagnostic procedure requiring sedation. If you’re scheduled for a procedure and not sure whether you should stop taking Naltrexone, please ask the doctor ordering the test or procedure. Additionally, you CANNOT resume Naltrexone until at least 48 hours after you have finished any prescribed medication for the procedure.