Description: Naltrexone acts as a competitive antagonist at opioid receptor sites which prevents the opiate effects and decreases desire to take opiates.


Absorption: Well absorbed from the GI tract. Peak plasma concentrations after about 1 hr.

Distribution: 20% bound to plasma proteins.

Metabolism: Extensively metabolised in the lvier. Undergoes considerable 1st-pass metabolism and may undergo enterohepatic recycling.

Excretion: Via urine (as <1% unchanged drug and as metabolites). Elimination half-life: Approx 4 hr.

  • Used for:
    • Prevention of opiate drug addicts to taking opiates again and serves as a part of a complete treatment program
    • Must not be used in those currently taking opiates as it may cause sudden withdrawal symptoms
    • Belongs to a class of drugs known as opiate antagonists


  • Also used to treat alcohol abuse by decreasing the desire to drink alcohol when used in conjuction with counseling, support, and lifestyle changes.


How to use naltrexone

  • Always refer to your doctors instructions before taking this medication. Duration and dosage will be determined by your medical condition and its response to the medication. Make sure to take this mediciation in the prescribed amount and time period even after symptoms disappear. Discontinuing the medication before completion of treatment may cause incomplete treatment of condition. If Symptoms persist, consult your doctor
  • Taken by mouth; With or without food, May be taken with antacids to prevent stomach upset; usually once a day
  • Do not use any opiates for at least 7 days before starting naltrexone

Inform your Physician if you start using drugs or alcohol again.

    • Minor side effects (if these symptoms persist or worsen, inform your doctor)
      • Nausea, headache, dizziness, anxiety, tiredness, and trouble sleeping may occur. In a small number of people, mild opiate withdrawal symptoms may occur, including abdominal cramps, restlessness, bone/joint pain, muscle aches, and runny nose


    • Serious widthrawal side effects (inform your doctor immediately)
      • abdominal cramps, nausea/vomiting, diarrhea, joint/bone/muscle aches, mental/mood changes (e.g., anxiety, confusion, extreme sleepiness, visual hallucinations), runny nose.
      • Rarely caused serious liver disease
        • persistent nausea/vomiting, severe stomach/abdominal pain, dark urine, yellowing eyes/skin.


    • Severe allergic reactions are rare. Get immediate medical help if you notice the following:

    Rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing

    • Precautions:
      • Inform your doctor
        • Allergy to the medication or any allergies
        • Medical History of current or recent use (in the last 7 to 14 days) of any type of opioid drug (such as morphine, methadone, buprenorphine), kidney disease, liver disease.


      • You should carry or wear medical identification stating that you are taking this drug so that appropriate treatment can be given in a medical emergency.


      • May cause dizziness



      • Should only be used when there is a clear need during pregnancy as it may harm an unborn baby. If you are planning to be pregnant or think you may be pregnant, discuss the risks and benefits of use with your doctor.


      • It is not known if this drug passes into breast milk. Before breast-feeding, consult your physician.




      Taking multiple drugs may affect how medications work and/or cause unwanted side effects. List down all the medications you are taking and inform your physician and pharmacist. Do not take, discontinue, or alter any dose of medications without prior approval of your physician.


      • Products that may interact with this medication include:
        • cough medication (e.g., dextromethorphan), disulfiram, diarrhea medication (e.g., diphenoxylate), narcotic medication (e.g., codeine, hydrocodone, propoxyphene), thioridazine


      • Labratory tests that may be affected:

      Drug tests

    • Overdose: If overdose is suspected, contact a poison control center or emergency room immediately



      Missed Dose

      If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and As soon as you remember, take a regular dose or if the time of the next dose is near, wait for it before taking another dose and resume your usual schedule. Do not increase the dose to compensate for the missed dose.



      • Room temperature
      • Do not expose to light and moisture
      • Do not store in the bathroom
      • Keep all medications away from pets and children





      Available Brands:


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