Hi Numb,
It is correct that 50mg is the lowest dose commercially manufactured. However, Low Dose Naltrexone is given in extremely small doses not available commercially and must be compounded. There is good information on it from CRPS pioneer and researcher Dr. Pradeep Chopra here.
Low Dose Naltrexone and chronic pain - Pradeep Chopra, MD | LDN Research Trust - Low Dose Naltrexone
It discusses compounding and dosage at the end of the article. Dr. Chopra does mention potential for liver problems at doses of 50mg and higher so not sure that would be best for you long term. LDN takes a while to work its magic so it is not something you'd take for just a brief time.
Hope this helps.