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Low Dose Naltrexone (LDN) Choices booklet

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Naltrexone is a drug developed initially to treat addiction to opiate-based drugs, such as heroin or morphine. It belongs to a class of medications called opiate antagonists (1).

Naltrexone delivered in lower doses – Low Dose Naltrexone (LDN) – has been used in the USA to treat the symptoms of autoimmune conditions, such as multiple sclerosis (MS), since 1985, and more recently has been used in Europe and the UK (1).

The low dose method of taking naltrexone was devised and developed by the late Dr Bernard Bihari, from New York. Dr Bihari was qualified in Internal Medicine, Psychiatry and Neurology (1).

LDN is used ‘off label’ as a treatment for the symptoms of many conditions including Crohn’s disease, fibromyalgia, chronic fatigue syndrome and Ulcerative Colitis – conditions with an autoimmune origin, or potential autoimmune origin (2).


‘I wish that doctors were more proactive, as I felt I had to do a lot of my own research into LDN, then I had the battle of getting it’


How Naltrexone works

As an opiate antagonist, naltrexone is thought to inhibit endorphins – the body’s natural painkiller. It is believed that by inhibiting endorphins, the body reacts by producing more. This increase in endorphins reduces pain and increases a sense of wellbeing.

Once the LDN has been processed by the body, the elevated endorphins produced as a result can now act together with the receptors and assist in regulating cell growth and immunity (3).


‘I have definitely had massive benefits taking LDN, it has worked really well for me’


Research into LDN

There have been many studies into the safety and effectiveness of LDN as a treatment for MS, mostly small trials, with mixed results.


‘I have taken LDN in the past but I found that it didn’t make any difference to me’


A six-month phase II pilot trial of 40 people with primary progressive MS was conducted by Dr M Gironi, with the main purpose of looking at safety and tolerability. This study found Low Dose Naltrexone to be well-tolerated by the patients who also reported an improvement of their symptoms, particularly spasticity, pain, fatigue and depression. There were also reported improvements to quality of life outcomes (4).

Another 17-week randomised trial was conducted in 2010 titled ‘The effect of Low-Dose Naltrexone on quality of life of patients with multiple sclerosis: a randomised placebo-controlled trial’. In this trial some people were given LDN, and some a placebo and it looked into the effects of LDN in relation to quality of life. Ninety-six people were enrolled in the trial – some with relapsing remitting MS and some with secondary progressive MS. This trial demonstrated the safety of LDN. However, the results on LDN’s effect on quality of life (as measured by physical and mental health) was not clearly proven, with no statistically significant differences shown between the LDN-dosed group and the placebo group (5).


‘I have been taking LDN since 2004 and feel certain it has improved most symptoms, and I feel it has slowed down progression’


A small scale study titled ‘Pilot trial of low-dose naltrexone and quality of life in multiple sclerosis’ was published in August 2010 to evaluate the efficacy of 4.5mg of naltrexone, taken each evening over an eight week period, on the quality of life of people with MS. Eighty participants with an MS diagnosis were enrolled, and 60 subjects completed the trial. The high rate of subject dropout and data management errors reduced the trial’s statistical influence. The study found that LDN was well tolerated and serious adverse events did not occur during the trial. LDN was associated with significant improvement on a mental health quality of life measure. The trial concluded that LDN significantly improved mental health quality of life and suggested that further studies with LDN in MS were warranted (6).


Accessing LDN in the United Kingdom

Naltrexone is licenced and used in the UK to manage opiate dependency (7), but LDN has not been licensed for the treatment of MS symptoms by the National Institute of Health & Care Excellence (NICE) and is not widely recommended for use to treat people with MS within the NHS. The use of LDN to manage MS symptoms is sometimes described as ‘off-label’ (8).


‘I have to pay privately. My GP was told she wasn’t allowed to prescribe it’


Many GP’s and neurologists are cautious, given the guidelines within the NHS, about prescribing LDN for the treatment of MS symptoms (9).

GP’s are often unfamiliar with LDN and the LDN Research Trust have published a useful factsheet that may be helpful. If you are considering LDN, the pack contains useful information for your GP or prescribing clinician. If you are able to obtain a prescription for LDN from your GP, you will be able to get LDN dispensed at the standard prescription rate. As LDN is unlicensed, your GP may refuse to prescribe it and you may need to gain a prescription privately (10).


‘It took many years for my consultant to agree to prescribe it. It was the MS nurse who finally persuaded her that it was helping patients in the USA. My own GP had to present a case for prescribing it. I still had to get the prescription from Scotland. I now get it on my prescription and have delivered from my local chemist. It has been a long slog trying to get to this state of affairs’


If you are unable to obtain an NHS prescription from your GP, your GP may be willing to write you a private prescription but will make a charge. You could also get in touch with a private specialist practice or one of the online GP services. You will be likely to be asked to provide them with a letter from your GP or neurologist confirming that you have MS, a summary of your medical history, including any other conditions you live with, and any existing medication you take.


‘I have a repeat prescription for LDN from a brilliant NHS Doctor who had to fight to allow me to have it. She has taken full responsibility for prescribing it to me. I send the prescription to Dickson chemist in Scotland’


If you have a private prescription you can obtain LDN from a specialist pharmacy. Dickson Chemist, based in Glasgow, have been prescribing LDN for some time and their lead pharmacist is also an advisor to the LDN Research Trust. You can read more about how to gain LDN in the LDN Research Trust’s factsheet (10).


‘My LDN is sent directly from Dickson chemist in Scotland after my neurologist forwards a prescription, but it is a private one so has to be paid for’


It is important to note that LDN obtained from sources other than a prescribing chemist cannot be guaranteed to contain LDN, or be safe. This is particularly true of LDN obtained from unregulated sources on the internet (10).


How to take LDN

According to the LDN Research Trust, the majority of people using LDN will have a positive impact on symptoms quite quickly after starting treatment. They also say that in less than 10% of people with MS that are treated, increased symptoms may be more severe or more prolonged than usual, lasting sometimes for several weeks. Rarely, symptoms may persist for two or three months before the appropriate beneficial response is achieved.


‘I take 3mls of LDN, adjusting dosage when needed. It has stopped my heat intolerance and twitching legs but has not stopped progression’


Your prescribing doctor will usually start the treatment of LDN at a very low dose and increase this gradually, making sure any increase does not cause some of the more common adverse effects. If you do experience any unpleasant side effects after starting LDN, talk to your prescribing doctor about reducing the dose for a period, before increasing it again.

Some of the common initial side effects from taking LDN are increased fatigue, sleep disturbance (if taken at night time) and increased spasticity however many people starting on LDN do not experience any side effects.

LDN is most commonly administered in liquid form. It is taken with a syringe of the same type used to give medications to infants. LDN is also available as a capsule at 3mg and 4.5mg doses or as sublingual drops, which are a higher dose to liquid LDN and are used by people who have trouble swallowing. The drops are placed under the tongue with a dropper (10).


Special precautions

It is strongly suggested by the LDN Research Trust that you should talk with your GP, MS nurse or neurologist if you are taking herbal medicines, or multiple medications or if you have renal or liver failure. If you experience liver issues you may need to be regularly monitored with additional blood tests.

According to the LDN Research Trust, LDN is compatible with steroids and some of the disease modifying treatments (DMT) for MS. If you are taking a DMT and are planning to start LDN it is suggested that you talk to your MS nurse or neurologist before starting LDN.

Some medicines are not compatible with LDN – particularly opiate-based painkillers (such as morphine).

If you are considering taking LDN, you should provide the prescribing doctor with your full medical history.

If you choose to start treatment with LDN please report any untoward or adverse effects immediately to your prescribing doctor so the treatment process may be re-assessed and modified if necessary (10).


Further information

If you are considering using LDN and wanted to do some further reading, then you could start with ‘The LDN Book’ edited by Linda Elsegood. In 2016 the editor of New Pathways magazine reviewed the book and said that Elsegood had gathered together a host of experts on the subject, all of whom had written in a warm and engaging way. They felt that although MS had to share a chapter with lupus the information was exhaustive, covering many facets of MS without being patronising or boring and explained what LDN could do and how it might be doing it (11). The book is available to purchase online from a variety of retailers.

For more information on the information above please see the following links. If you would like to discuss anything mentioned in this booklet then please call our helpline free on 0800 783 0518. If you would like a plain text version of this booklet please email


Click here to download your free LDN Choices booklet




  1. What is LDN?, The LDN Research Trust. Accessed 16 October 2018.
  2. What is LDN Used for?, is a public information project of the MedInsight Research Institute. Accessed 10 October 2018.
  3. How Does LDN Work?, is a public information project of the MedInsight Research Institute. Accessed 10 October 2018.
  4. Multiple Sclerosis Journal, A pilot trial of low-dose naltrexone in primary progressive multiple sclerosis. Gironi et al. Published September 2008. Accessed 15 October 2018.
  5. Multiple Sclerosis Journal, The effect of low-dose naltrexone on quality of life of patients with multiple sclerosis: a randomized placebo-controlled trial. Sharafaddinzadeh et al. Published August 2010. Accessed 16 October 2018.
  6. Annals of neurology, Pilot trial of low-dose naltrexone and quality of life in multiple sclerosis, Cree BA et al. Published August 2010. Accessed 16 October 2018.
  7. Summary of Product Characteristics – Nalorex. Bristol-Myers Squibb Pharmaceutical Ltd. Page last reviewed February 2014. Accessed on 16 October 2018.
  8. Healthline, Can Low-dose Naltrexone Help with MS? Brown, M. Page reviewed 28 June 2018. Accessed 16 October 2018.
  9. Specialist Pharmacy Service, What is the evidence for low dose naltrexone for treatment of multiple sclerosis? Q&A 69.6. Published 16 February 2017, updated 12 March 2018. Accessed 16 October 2018.
  10. Low-dose Naltrexone (LDN) Fact Sheet 2015, LDN Research Trust. Accessed 16 October 2018.
  11. Johnson, Kahn. Read all about it: The LDN Book. New Pathways. Issue 96, March/April 2016. Page 37.