Naltrexone

Generic name: Naltrexone, Naltrexone Hydrochloride
Brand names: Vivitrol
Dosage form: extended-release intramuscular injection (powder for suspension), oral tablet

Usage of Naltrexone

Naltrexone is a prescription medication used to treat alcohol use disorder and opioid use disorder. It helps you stop using these substances and remain off them.

Naltrexone belongs to a class of drugs known as opioid antagonists and works by blocking the mu opioid receptor. It blocks the effects of alcohol and opioid medications, preventing the intoxication these substances cause. Naltrexone also modifies how the hypothalamus, pituitary gland and adrenal gland (hypothalamic-pituitary-adrenal axis, HPA axis) interact to suppress the amount of alcohol consumed.

Naltrexone comes as an extended-release intramuscular injection (Vivitrol) and as oral tablets. The branded versions of naltrexone tablets (Revia, Depade) have been discontinued, but generic versions are available.

Naltrexone tablets were first approved by the US Food and Drug Administration (FDA) in 1984. In 2006, the FDA also approved Vivitrol, the extended-release intramuscular injection form of naltrexone.

Naltrexone side effects

Serious side effects of naltrexone include:

See 'Important information' above

Depressed mood. Sometimes this leads to suicide, or suicidal thoughts, and suicidal behavior. Tell your family members and people closest to you that you are taking this medication. You, a family member, or the people closest to you should call your healthcare provider right away if you become depressed or have any of the following symptoms of depression, especially if they are new, worse, or worry you:

You feel sad or have crying spells.

You are no longer interested in seeing your friends or doing things you used to enjoy.

You are sleeping a lot more or a lot less than usual.

You feel hopeless or helpless.

You are more irritable, angry, or aggressive than usual.

You are more or less hungry than usual or notice a big change in your body weight.

You have trouble paying attention.

You feel tired or sleepy all the time.

You have thoughts about hurting yourself or ending your life.

You have hallucinations.

Pneumonia. Some people receiving this treatment have had a certain type of pneumonia that is caused by an allergic Reaction. If this happens to you, you may need to be treated in the hospital. Tell your healthcare provider right away if you have any of these symptoms during treatment with naltrexone:

shortness of breath or wheezing

coughing that does not go away

Serious allergic reactions. Serious allergic reactions can happen during or soon after an injection of naltrexone. Tell your healthcare provider or get medical help right away if you have any of these symptoms of a serious allergic reaction.

skin rash

swelling of your face, eyes, mouth, or tongue

trouble breathing or wheezing

chest pain

feeling dizzy or faint

Common side effects of naltrexone include:

nausea. Nausea may happen when you first start this medication, but it can improve overtime.

vomiting

sleepiness

anxiety

headache

restlessness

nervousness

abdominal pain

painful joints

muscle pain and muscle cramps

weakness

decreased appetite

heart palpitations

increased heart rate

ECG changes

libido disorders

thirst

dizziness

increase tear secretion

chest pain

diarrhea

constipation

rash

delayed ejaculation and erectile dysfunction

increased energy

irritability

increased sweating

affective disorders

cold symptoms

trouble sleeping

toothache

Tell your healthcare provider if you have any side effect that bothers you or that does not go away.

These are not all the side effects of this medication. For more information, ask your healthcare provider or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Before taking Naltrexone

Tell your doctor if you are pregnant or plan to become pregnant. It is not known if naltrexone will harm your unborn baby. This medication should only be used during pregnancy if the potential benefits justifies the potential risk to the fetus.

Tell your doctor if you are breastfeeding. It is not known if naltrexone passes into your milk when it is administered by IM injection, and it is not known if it can harm your baby. Naltrexone from tablets passes into breast milk. Talk to your healthcare provider about whether you will breastfeed or take this medication. You should not do both.

How to use Naltrexone

Tablets:

Alcoholism: The recommended dose is 1 tablet (50 mg) once a day

Opioid Dependence: Start with half a tablet (25 mg) and if no withdrawal signs occur increase to the dose to 1 tablet (50 mg) a day from then on

Intramuscular injection:

The recommended dose is naltrexone 380 mg delivered intramuscularly (IM) as a gluteal injection, every 4 weeks or once a month, alternating buttocks for each subsequent.

See the full prescribing information for further details about naltrexone dosing.

Warnings

Naltrexone can cause serious side effects, including:

1. Risk of opioid overdose.

You can accidentally overdose in two ways.

Naltrexone blocks the effects of opioid drugs. Do not take large amounts of opioids, including opioid-containing medicines, such as heroin or prescription pain pills, to try to overcome the opioid-blocking effects of this medication. This can lead to serious injury, coma, or death.

After you receive a dose of the extended-release injection form of this medication, its blocking effect slowly decreases and completely goes away over time. If you have used opioid street drugs or opioid-containing medicines in the past, using opioids in amounts that you used before treatment can lead to overdose and death. You may also be more sensitive to the effects of lower amounts of opioids:

after you have gone through detoxification

when your next Naltrexone injection is due

if you miss a dose of this medication

after you stop naltrexone treatment It is important that you tell your family and the people closest to you of this increased sensitivity to opioids and the risk of overdose. You or someone close to you should call 911 or get emergency medical help right away if you:

have trouble breathing

become very drowsy with slowed breathing

have slow, shallow breathing (little chest movement with breathing)

feel faint, very dizzy, confused, or have unusual symptoms Talk to your healthcare provider about naloxone, a medicine that is available to patients for the emergency treatment of an opioid overdose. Call 911 or get emergency medical help right away in all cases of known or suspected opioid overdose, even if naloxone is administered.

2. Severe reactions at the site of the naltrexone injection (injection site reactions). Some people have had severe injection site reactions, including tissue death (necrosis), while receiving naltrexone injections. Some of these injection site reactions have required surgery. This medication must be injected by a healthcare provider. Call your healthcare provider right away if you notice any of the following at any of your injection sites:

intense pain

the area feels hard

large area of swelling

lumps

blisters

an open wound

a dark scab

Tell your healthcare provider about any reaction at an injection site that concerns you, gets worse over time, or does not get better by two weeks after the injection.

3. Sudden opioid withdrawal.

Anyone who receives naltrexone must not use any type of opioid (must be opioid-free) including street drugs, prescription pain medicines, cough, cold, or diarrhea medicines that contain opioids, or opioid dependence treatments, Buprenorphine or methadone, for at least 7 to 14 days before starting this medication. Using opioids in the 7 to 14 days before you start receiving treatment may cause you to suddenly have symptoms of opioid withdrawal when you receive treatment. Sudden opioid withdrawal can be severe, and you may need to go to the hospital.

You must be opioid-free before receiving naltrexone unless your healthcare provider decides that you don't need to go through detox first. Instead, your doctor may decide to give this medication in a medical facility that can treat you for sudden opioid withdrawal.

4. Liver damage or hepatitis. Naltrexone can cause liver damage or hepatitis.

Tell your healthcare provider if you have any of the following symptoms of liver problems during treatment with this medication:

stomach area pain lasting more than a few days

dark urine

yellowing of the whites of your eyes

tiredness

Your healthcare provider may need to stop treating you with this medication if you get signs or symptoms of a serious liver problem.

You must inform every doctor that treats you that you are taking Naltrexone. Non-opiate based anesthetics should be used if you require an anesthetic in an emergency situation. If you have to use opiate containing anesthetics, you may need higher doses than usual. You may also be more sensitive to the side-effects (breathing difficulties and circulatory problems).

What other drugs will affect Naltrexone

Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements.

Especially tell your healthcare provider if you take any opioid-containing medicines for pain, cough or colds, or diarrhea.

If you are being treated for alcohol dependence but also use or are addicted to opioid-containing medicines or opioid street drugs, it is important that you tell your healthcare provider before starting naltrexone to avoid having sudden opioid withdrawal symptoms when you start treatment.

Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist when you get a new medicine.

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