LDN is short for Low Dose Naltrexone.
Naltrexone is a drug that was approved by the FDA in 1985 to treat opiate dependence. It is marketed under the trade names, ‘Revia®’ and ‘Depade®’, and in some countries (including the United States), an extended-release formulation is available as ‘Vivitrol®’. Naltrexone is commonly used at a dose of 50mg–100mg daily for treating opiate dependence.
The term ‘LDN’ refers to the use of naltrexone at low doses; specifically between 3mg and 10mg per day. Naltrexone exhibits novel and paradox effects when administered as these low doses, as discovered by Dr. Ian S. Zagon and his team at Hershey Medical Center, Penn State University in 1980.
Since this discovery, numerous laboratory and animal studies have been carried out to investigate the novel effects of LDN in cancer and autoimmune disorders. In 2007, results of the first clinical trial using LDN were published (Smith JP et al. Am J Gastroenterol. 2007;102(4):820-8), followed by publication of a study on multiple sclerosis in 2008 (Gironi M et al. Multiple Sclerosis. 2008;14(8):1076-83) and fibromyalgia in 2009 (Younger J and Mackey S. Pain Med. 2009;10(4):663-72). Further studies are ongoing.
LDN is a member of a group of agents collectively known as ‘Modulators of Opioid and Receptor Activity’ (‘MORAs’). Another related ‘MORA’ drug discussed on this website is OGF.