I have been a proponent and a prescriber of low dose naltrexone for a long time. The LDN Book by Linda Elsegood was written last year. It will allow more physicians to understand the uses of LDN. There is also a LDN web page on the Internet.
The range I use is from 1.0 mg to 4.5 mg although I have used 6.0 mg. Naltrexone was originally developed to block opiate receptors. It is used today as Narcan. It has been in the media since police officers can officially use it in the field.
I have used LDN for multiple sclerosis, lupus, Lyme disease, inflammatory bowel disease, Hashimoto's thyroiditis, and autism.
The only side effect is sleep disturbance in the way of dreams.