Finally, a controlled before-after study grounded on the Norwegian Prescription Database (NorPD) compared prescriptions to RA patients one year prior to and one year after starting LDN and found a reduction in the use of NSAID, opioids, and DMARDs such as methotrexate and anti TNF-alpha drugs.19 Additionally to its analgesic and anti-inflammatory properties, LDN may work as an immunomodulating agent by directly binding on the opioid growth factor receptor (OGFr) within immune and tumour cells.26 This evidence concerns the gene OGFR and rheumatoid arthritis.