Naltrexone

(Nalorex / ReVia)

 

Naltrexone is a medication that also blocks the effects of morphine, heroin, and other opiates. Naltrexone has long-lasting effects, ranging from 2-3 days when taking the oral form or up to 12 months if an implant is used. It blocks the pleasurable effects of heroin by blocking the opiate receptors in the brain. This means that even when heroin is taken, the patient cannot feel the pleasure effects of it. Care must be taken though as an overdose can still occur, especially as the user might take more and more of the drug trying to get an effect, not realising how much they have taken. In the UK it is often referred to as ‘blockers’. In the USA it may be referred to as ReVia.  You have to be free from all opiates for at least 4 days before taking this, or else you will suffer very badly. Its like going into an immediate, severe turkey. 

 

Naltrexone implants and naltrexone tablets taken regularly seem able to block even large amounts of heroin or other opiates. Many patients test out the blockade in the first few days and are reassured to find it works. However, it can be dangerous to try to overcome the blockade by using enormous amount especially when the implant may be starting to wear off, i.e. any time after about five weeks, because you could be at serious risk of a potentially lethal overdose. When you have been clean for a few weeks, you lose your tolerance of opiates. That means that even quite a small amount of heroin could kill you if you were not protected by naltrexone. Abstinence from opiates has risks as well as benefits. There is a sad and steady trickle of overdose deaths in patients who had been clean for weeks or months and thought they deserved a little treat. DON'T LET THIS HAPPEN TO YOU.

Being on naltrexone means that opiates will be ineffective for pain relief if you have an accident or need surgery. Fortunately, there are pain-killing drugs which are not blocked by naltrexone. These include nitrous oxide (laughing gas) which most ambulances carry and the anaesthetic drug ketamine. Make sure that you always wear your naltrexone warning card and/or wear your warning tag.

Some possible unwanted effects of naltrexone

Naltrexone causes few side effects in patients who are not taking opiate drugs. Some of the side effects listed below can occur only if you are still taking opiate drugs. Side effects that you should report to your prescriber or health care professional as soon as possible:

  • blurred vision or other eye problems

  • confusion

  • difficult or frequent passing of urine

  • difficulty in awaking from sleep

  • earache, ringing in the ears

  • fast or pounding heartbeat (palpitations)

  • fever

  • hallucinations (seeing and hearing things that are not really there)

  • mood changes

  • nose bleeds

  • pain, tenderness, or color changes in the legs or feet

  • shortness of breath

  • skin rash, itching

  • slowed breathing

  • swelling of the face, feet, or lower legs

  • swollen glands

  • weight gain

  • yellow color of your eyes or skin

Liver function tests

Every patient should have a liver function test before treatment and every 3 months during treatment. This is because naltrexone is removed from the body by the liver and in rare cases can cause liver problems. For this reason the following symptoms should be reported to your doctor immediately:

  • Abdominal pain lasting more than a few days 

  • White or light bowel movement 

  • Dark urine 

  • Yellow eyes or skin (jaundice)

 

Other Medications containing Opiates

Below are some examples of medications that may contain opiates and may be blocked by naltrexone. As with heroin it can be fatal to try and overcome the blockade of these drugs:

  • Dihydrocodeine, codeine, co-codamol, co-dydramol, co-proxamol

  • Any painkiller except paracetamol or anti-inflammatory such as Ibuprofen

  • Cough medicines and anti-diarrhea medication

 

 

 

Oral Naltrexone

After being clean of opiates for a minimum of 4 days and passing a drugs test, you will normally be given a test injection of Naloxone (approx 10mg). This is to make sure that you don't have a bad reaction to the drug. The injection only lasts for approximately 2-3 hours and isn't as strong, whereas the tablets will be effective for 2 - 3 days. You will be asked to stay on site for an hour after having the injection so that they can monitor you. If all is well, they will then ask you to take half a tablet and will give you your prescription. If you are asked to go into a unit to get Naltrexone and you have used in the past few days, please let them know and DON'T take the injection or tablets, as you will suffer badly. You are much better to admit to them that you have used, as they will find out after an hour anyway and you will suffer badly. People have had to be hospitalized as a result of taking Naltrexone with opiates still in their system.

 

You will be given 50mg tablets to take each day.  Each tablet is effective for about two - three days, meaning that if you wanted to start using opiates again you would need to stop taking them three days beforehand otherwise you would get no effect.  This is why Naltrexone is so good, as if you are feeling weak you know that you wont be able to feel the heroin so what is the point in using.  You might consider not taking your tablet so that you can use but before the three days is up, you will probably have realised that you are being stupid and have started taking your tablets again.

 

 

Naltrexone Implant

Read more about the implant and see some pictures of it, including me and my husbands shortly after insertion.

 

 

NALTREXONE INJECTABLE (Vivitrol)

Naltrexone is now available in the US as an FDA-approved injectable depot preparation that lasts for a month. Although this dosage form is not approved for opioid treatment (neither is the implant) the results are very good. The brand name for the depot preparation is VIVITROL.

 

Click here to read the handbook 'Treatment Choices: Naltrexone' by HIT.

 

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Last updated: 12 November 2007