Low dose naltrexone

Naltrexone is a drug normally used to treat drug dependence. Dosage for standard use is around 50mg. Low-dose Naltrexone (LDN) involves usage around 4mg per day and is off-label. Some patients claim LDN helps reduce symptoms in some ME/CFS, MS, and autoimmune disease patients[ref].

Jared Younger did a study that concluded "... low-dose naltrexone may be an effective, highly tolerable, and inexpensive treatment for fibromyalgia."

A second study concluded "specific and clinically beneficial impact on fibromyalgia pain."

There is an online patient community where patients with various diseases discuss their experiences taking Low-dose Naltrexone.

Availability
Naltrexone is a prescription drug in many countries[ref].

In the UK Dickson Chemist in Glasgow dispenses low-dose Naltrexone in various forms, with a valid prescription. They will usually put patients in contact with private doctors who will consider writing a prescription.