Low Dose Naltrexone

Naltrexone was originally discovered in 1963 as an opioid receptor antagonist. This means that it blocks the actions of opioid medicines like morphine and has been used since 1984 for the treatment of opioid addiction in the dose range of 50-100mg per day. Low Dose Naltrexone (LDN) refers to using a dose 1/10th of the normal dose and is usually 1.5mg-4.5mg daily. This dosage is not commercially available and we make it in our compounding lab for each individual. A prescription is required and your GP and/or Specialist will determine if LDN is suitable for you.

When used in low doses, LDN appears to have paradoxical analgesia and anti-inflammatory effects that have been shown to reduce symptom severity in many different chronic pain disorders. LDN is thought to work independently from its action on opioid receptors by blocking glial cells which are a type of central immune cell. When activated the glial cells are thought to cause proinflammatory effects that result in pain sensitivity, fatigue, cognitive disruptions, and sleep disorders.

Blocking this action of glial cells is thought to provide neuroprotective and analgesic effects in many conditions like fibromyalgia, multiple sclerosis, crohn’s disease and some other chronic pain conditions. (1) Most research suggests that LDN takes about one month to start showing pain reductions and therefore it would be suggested to trial for 3-6 months. The most common starting dose is 1.5mg and increasing to 4.5mg. It is important to not keep escalating the dose higher as the higher doses can potentially lose the paradoxical effect mentioned above.

Most studies conclude that LDN is well tolerated and has not reported any serious side effects. (2) Our Pharmacist’s have taken a special interest in pain management, researching the efficacy of existing therapies and constantly looking for new innovations. If you would like any further information about LDN, please contact us on 3263 1133.

If you would like more information about our Chronic Pain Medication Reviews, click here or make an appointment here.


  1. Younger J et al, The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic pain, Clin Rheumatol. 2014; 33(4): 451–459, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3962576
  2. Bolton M et al, Serious adverse events reported in placebo randomised controlled trials of oral naltrexone: a systematic review and meta-analysis, BMC Medicine 2019; 17(10), https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-018-1242-0