Medically reviewed on June 7, 2018
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
- Powder for Suspension, Extended Release
Therapeutic Class: Ethanol Dependency
Pharmacologic Class: Opioid Antagonist
Uses For This Medicine
Naltrexone injection is used to help narcotic dependents who have stopped taking narcotics to stay drug-free. It is also used to help alcoholics stay alcohol-free. The medicine is not a cure for addiction. It is used as part of an overall program that may include counseling, attending support group meetings, and other treatment recommended by your doctor.
Naltrexone is not a narcotic. It works by blocking the effects of narcotics, especially the "high'' feeling that makes you want to use them. It also may block the "high'' feeling that may make you want to use alcohol. It will not produce any narcotic-like effects or cause mental or physical dependence. It will not prevent you from becoming impaired while drinking alcohol.
Naltrexone will cause withdrawal symptoms in people who are physically dependent on narcotics. Therefore, naltrexone treatment is started after you are no longer dependent on narcotics. The length of time this takes may depend on which narcotic you took, the amount you took, and how long you took it. Before you start using naltrexone, be sure to tell your doctor if you think you are still having withdrawal symptoms.
Naltrexone is to be given only by or under the direct supervision of your doctor.
Before Using This Medicine
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For naltrexone, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to naltrexone or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of naltrexone injection in the pediatric population. Safety and efficacy have not been established.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of naltrexone injection in the elderly.
|All Trimesters||C||Animal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.|
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with Medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving naltrexone, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using naltrexone with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Morphine Sulfate Liposome
- Opium Alkaloids
Using naltrexone with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using naltrexone with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Interactions with Food/Tobacco/Alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of naltrexone. Make sure you tell your doctor if you have any other medical problems, especially:
- Bleeding problems (eg, hemophilia) or
- Kidney disease, moderate to severe or
- Liver disease, mild to moderate or
- Lung or breathing problems or
- Thrombocytopenia (low platelets in the blood)—Use with caution. May make these conditions worse.
- Drug dependence, especially narcotic abuse or dependence, history of or
- Failed the naloxone challenge test (medical test to check your dependence to opioid medicine) or
- Liver disease (including acute hepatitis), severe or
- Opioid withdrawal, acute or
- Positive urine test for opioids or
- Receiving opioid analgesics (eg, morphine)—Should not be used in patients with these conditions.
Proper Use of This Medicine
A nurse or other trained health professional will give you naltrexone. Naltrexone is given as a shot into the buttocks (gluteal) muscle. It is usually given every 4 weeks or once a month.
Naltrexone injection should only be given to alcohol-dependent patients who can abstain from drinking alcohol and does not need an overnight stay in the hospital.
If you miss your scheduled dose, call your doctor to make another appointment as soon as possible.
Naltrexone usually comes with a Medication Guide. Read the information carefully and make sure you understand it before receiving naltrexone. If you have any questions, ask your doctor.
Precautions While Using This Medicine
It is very important that your doctor check your progress at regular visits. Your doctor may want to do certain blood and urine tests to see if the medicine is causing unwanted effects.
Naltrexone may cause serious problems with your liver. Call your doctor right away if you start having dark urine, pain in the upper stomach, or yellowing of the eyes or skin while you are using naltrexone.
Naltrexone may increase your risk of having a lung disease called eosinophilic pneumonia. Tell your doctor right away if you have coughing or trouble breathing after receiving naltrexone.
Naltrexone may cause a serious type of allergic reaction called anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using naltrexone.
You will need to stop using opioids (narcotics) for at least 7 to 10 days before you can start receiving naltrexone injection. Your doctor may need to do the naloxone challenge test or a urine test for opioids to make sure you are opioid-free.
Naltrexone blocks the "high" feeling you get from narcotic (opioid) drugs, including heroin. Since naltrexone injection may make you more sensitive to lower doses of opioids than you have previously used, you should not use heroin or any other narcotic drugs to overcome what the medicine is doing. You could overdose and develop serious problems.
Naltrexone may increase thoughts of suicide. Tell your doctor right away if you start to feel more depressed. Also tell your doctor right away if you have thoughts about hurting yourself. Report any unusual thoughts or behaviors that trouble you, especially if they are new or get worse quickly. Make sure your caregiver knows if you feel tired all the time, sleep a lot more or a lot less than usual, feel hopeless or helpless, or if you have trouble sleeping, get upset easily, have a big increase in energy, or start to act reckless. Also tell your doctor if you have sudden or strong feelings, such as feeling nervous, angry, restless, violent, or scared.
Remember that use of naltrexone is only part of your treatment. Be sure that you follow all of your doctor's orders, including seeing your therapist and/or attending support group meetings on a regular basis.
Do not try to overcome the effects of naltrexone injection by taking narcotics. To do so may cause coma or death. You may be more sensitive to the effects of narcotics than you were before beginning naltrexone treatment.
Naltrexone injection also blocks the useful effects of narcotics. Always use a non-narcotic medicine to treat pain, diarrhea, or a cough. If you have any questions about the proper medicine to use, check with your doctor.
Naltrexone injection will not prevent you from becoming impaired when you drink alcohol. Do not take naltrexone in order to drive or perform other activities while under the influence of alcohol.
After naltrexone is injected into your body, it is impossible to remove it.
It is recommended that you carry an identification card stating that you are receiving naltrexone injection. You may also need to carry a letter to let others know you are receiving naltrexone in case you have a medical emergency.
You may experience a serious reaction at the site of the naltrexone injection that includes pain, swelling, tenderness, bruising, itching, and redness. Contact your doctor right away if this skin reaction does not improve or becomes worse within two weeks after receiving the injection. Your doctor should also refer you immediately to a surgeon.
You may experience nausea after the first injection of naltrexone that should be mild and subside a few days afterwards. You will be less likely to have nausea with your next injections.
Naltrexone may cause some people to become dizzy, drowsy, or less alert than they are normally. If any of these side effects occur, do not drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert while you are receiving naltrexone injection.
Before you have any medical tests, tell the medical doctor in charge that you are receiving naltrexone. The results of some tests may be affected by naltrexone.
This Medicine Side Effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor or nurse immediately if any of the following side effects occur:
- Bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
- body aches or pain
- difficulty with breathing
- dryness or soreness of the throat
- ear congestion
- feeling sad or empty
- lack of appetite
- loss of interest or pleasure
- loss of voice
- nasal congestion
- runny nose
- sore throat
- tender, swollen glands in the neck
- trouble concentrating
- trouble sleeping
- trouble swallowing
- unusual tiredness or weakness
- voice changes
Incidence not known
- Abdominal or stomach cramps or pain
- arm, back, or jaw pain
- black, tarry stools
- bladder pain
- bloody or cloudy urine
- bloody stools
- blurred vision
- chest pain or discomfort
- chest tightness or heaviness
- confusion as to time, place, or person
- cough producing mucus
- decreased urination
- difficult, burning, or painful urination
- dilated neck veins
- dizziness or lightheadedness
- dry mouth
- extreme fatigue
- false or unusual sense of well-being
- fast, irregular, pounding, or racing heartbeat or pulse
- frequent urge to urinate
- general feeling of discomfort or illness
- hallucinations or seeing, hearing, or feeling things that are not there
- headache, severe and throbbing
- holding false beliefs that cannot be changed by fact
- increase in heart rate
- increase in white blood cells
- irregular breathing
- itching, pain, redness, swelling, tenderness, or warmth on the skin
- joint or muscle pain
- lower back or side pain
- numbness or tingling of the face, hands, or feet
- pain or discomfort in the arms, jaw, back, or neck
- pain, redness, or swelling in the arm or leg
- pounding in the ears
- rapid breathing
- redness and soreness of the eyes
- severe nausea or vomiting
- skin rash
- slow or fast heartbeat
- sores in the mouth
- stomach cramps or pain
- sudden shortness of breath or troubled breathing
- sunken eyes
- swelling of the face, fingers, feet, or lower legs
- swollen, painful, or tender lymph glands in the neck, armpit, or groin
- tightness in the chest
- tooth or gum pain
- unusual excitement, nervousness, or restlessness
- vomiting of blood or material that looks like coffee grounds
- watery or bloody diarrhea
- weight gain
- wrinkled skin
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
- Sleepiness or unusual drowsiness
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- Difficulty with moving
- muscle stiffness
- swelling or redness in the joints
Incidence not known
- Bleeding after defecation
- bloated or full feeling
- change in taste
- decreased interest in sexual intercourse
- excess air or gas in the stomach or intestines
- feeling of warmth
- feeling unusually cold
- inability to have or keep an erection
- increased sweating
- loss in sexual ability, desire, drive, or performance
- loss of taste
- night sweats
- passing gas
- redness of the face, neck, arms, and occasionally, upper chest
- relaxed and calm
- sudden sweating
- uncomfortable swelling around anus
- unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
- weight loss
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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