Naltrexone (Nalorex) is a drug used to treat people with addictions. Following anecdotal reports that low doses help the symptoms of people with a wide range of conditions, there have been a few pilot studies of low dose naltrexone (LDN) in multiple sclerosis.

Research into LDN and multiple sclerosis

A study in Milan involved 40 people with primary progressive MS taking 4mg/day LDN for six months. The results showed LDN was safe and well tolerated. There was a significant reduction in spasticity during the trial, but half the participants reported an increase in pain. There were no significant changes to measures of fatiguedepression or quality of life.

A study at the University of California looked at the effects of LDN on quality of life in 80 people with MS. Results showed LDN significantly improved quality of life (specifically mental health, pain, and self-reported cognitive function.) However, no impact was observed on symptoms such as fatiguebowel and bladder control, sexual satisfaction and visual function. Vivid dreaming was reported during the first week of treatment, but no other adverse effects were reported.

A second study of quality of life in 96 people with relapsing and secondary progressive MS found that there were no significant differences on a wide range of quality of life measures betwen those taking placebo and those taking LDN for 17 weeks.

A small study comparing people who took LDN only or Copaxone with or without LDN found that scores for timed walk tests, MRI data and liver enzyme levels were similar.  LDN was shown to be safe and well tolerated.  The study was primarily looking at LDN safety in the long-term rather than at efficacy.

How LDN works

It is thought that LDN works by encouraging the body to produce endorphins which alters the action of the immune system.

How LDN is given

LDN is taken orally, either as capsules or in a liquid form.

Side effects and contraindications

The low dose used in MS is less than a tenth of the dose used to treat addictions, and the trials that have taken place report that LDN is not associated with any significant side effects. The full strength drug should not be used in conjunction with an opioid-containing medication, or by people with hepatitis or liver problems.

Treatment with LDN

As naltrexone is a licensed drug in the UK, it can be prescribed for conditions other than that for which it is licensed if a doctor feels that it is an appropriate treatment. Drugs prescribed 'off licence' are the direct responsibility of the prescribing doctor, who will need to be convinced that the treatment is safe and potentially effective. Although LDN is relatively inexpensive, funding for off licence prescriptions may not be available via the NHS.


  • Gironi M, et al. A pilot trial of low-dose naltrexone in primary progressive multiple sclerosis. Multiple Sclerosis 2008;14(8):1076-1083. Summary
  • Cree BA, et al. Pilot trial of low-dose naltrexone and quality of life in multiple sclerosis. Annals of Neurology 2010;68(2):145-150. Summary
  • Sharafaddinzadeh N, et al. The effect of low-dose naltrexone on quality of life of patients with multiple sclerosis: a randomized placebo-controlled trial. Multiple Sclerosis 2010;16(8):964-969. Summary
  • Ludwig MD, et al Long-term treatment with low dose naltrexone maintains stable health in patients with multiple sclerosis. Multiple Sclerosis Journal - Experimental, Translational and Clinical 2016;2:1-11. Read the full article

Last updated: 14 October 2016
Last reviewed: 3 June 2013

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