Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Revia (Naltrexone). If you are concerned about side effects, discuss the risks and benefits of Revia (Naltrexone) with your doctor.

The following side effects have been reported by at least 1% of people taking Revia (Naltrexone). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal pain or cramps
• anxiety
• chills
• Constipation
• decreased libido
• delayed ejaculation
• difficulty sleeping
• drowsiness
• Dry Mouth
• fatigue
• feeling down
• headache
• increased energy
• increased thirst
• indigestion
• irritability
• joint and muscle pain
• loss of appetite
• low energy
• nausea
• nervousness
• vomiting
• weight changes

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• dizziness
• increased blood pressure
• signs of liver problems (e.g., nausea, vomiting, Diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• increased blood pressure
• skin rash
• symptoms of a cold (e.g., nasal congestion, runny nose, sneezing, sore throat, excess phlegm, cough, hoarseness)
• symptoms of Depression (e.g., low energy, feelings of worthlessness, guilt, helplessness or hopelessness)
• symptoms of narcotic withdrawal (e.g., tearfulness, nausea, abdominal cramps, restlessness, bone or joint pain, muscle pain, nasal irritation)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• attempts at suicide or thoughts of suicide
• rapid or irregular heartbeat
• signs of an allergic reaction (such as difficulty breathing, Hives, skin rash, swelling of the face or throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Revia (Naltrexone).

Each pale yellow, film-coated, capsule-shaped tablet, engraved with "R11" on one side and with "50" and a bisect on the other side, contains 50 mg of Revia (Naltrexone) HCl. Nonmedicinal ingredients: colloidal silicon dioxide, crospovidone, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and Pale Yellow Opadry YS-1-6378-G.

Do not take Revia (Naltrexone) if you:

• are allergic to Revia (Naltrexone) or to any of the ingredients of the medication
• are dependent upon opiates, including if you are receiving opiate agonists (e.g., methadone)
• are experiencing opiate withdrawal
• are receiving opiate analgesics (e.g., narcotics medications such as Oxycodone and Codeine)
• have a urine test that is positive for opiates
• have acute hepatitis or liver failure
• have failed the NARCAN challenge (a test used to determine if you have used opiates)

There may be an interaction between Revia (Naltrexone) and any of the following:

• disulfiram
• Glyburide
• opiate-containing medications (e.g., codeine, Morphine, oxycodone)
• Nabilone
• Naloxegol

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Revia (Naltrexone). Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should take Revia (Naltrexone).

Accidental ingestion: If you are dependent on narcotics and you accidentally ingest Revia (Naltrexone), you could experience severe symptoms of withdrawal including confusion, nausea, shakiness, sweating, anxiety, visual hallucinations, vomiting, or diarrhea. Do not give Revia (Naltrexone) to anyone else, especially people who are dependent on opiate drugs.

Alcohol: You should not drink alcohol while taking Revia (Naltrexone) as this could damage your liver.

Interference with opiate-containing mediations: Because Revia (Naltrexone) works by blocking the effects of opiates, it may interfere with other medications that contain opiates such as certain cough and cold medications, antidiarrheal medications, and some analgesics (pain medications). Talk to your doctor or pharmacist about non-opiate containing alternatives.

Kidney function: If you have reduced kidney function your doctor may lower your dose of Revia (Naltrexone). Your doctor may also request that you have regular kidney function tests while you are taking Revia (Naltrexone).

Liver function: Revia (Naltrexone) can cause liver injury. If you have reduced liver function your doctor may lower your dose of Revia (Naltrexone). Your doctor may also request that you have regular liver function tests while you are taking Revia (Naltrexone). If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Overdose: If you accidentally overdose on Revia (Naltrexone), seek medical attention immediately.

Suicide: People with substance abuse problems are at a higher risk of suicide. The use of Revia (Naltrexone) does not lower this risk.

Taking opioid drugs: If you attempt to overcome the blocking effects of Revia (Naltrexone) by taking opiates, this may result in breathing difficulties and death. Do not take opiates while you are on Revia (Naltrexone). Furthermore, you may be more sensitive to lower doses of opiates after treatment with Revia (Naltrexone). A smaller dose than previously used may be required to achieve the same effect.

Treatment of alcohol dependence: The use of Revia (Naltrexone) for the treatment of alcohol dependence has only been studied for a dosage regimen of 50 mg once daily for up to 12 weeks. The efficacy of Revia (Naltrexone) beyond 12 weeks in this population is not known.

Pregnancy: Revia (Naltrexone) should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Revia (Naltrexone), contact your doctor immediately.

Breast-feeding: It is not known if Revia (Naltrexone) passes into breast milk. If you are a breast-feeding mother and are taking Revia (Naltrexone), it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using Revia (Naltrexone) have not been established for children less than 18 years of age.