Dose - How safe is Fentanyl for a first time user with no opiod tolerance?

[TOXIN]

Hi all, this is my very first post on these forums.

I'll make this as brief as possible but please read through the whole thing as it is of extreme importance that you understand this as I dont want to risk my wellbeing.

I was given fentanyl patches by the doctors at my pain managment clinic for severe and painful detereorating joint and muscle condition, but im reluctant to start on the patches as ive heard some negative things about them. The reason for my hesitation is that I have a severe chemical sensitivity which developed after I overdosed on recreational drugs 8 years ago and it left me disabled with a neurological condition known as Autonomic Dysfunction (Dysautonomia) after suffering severe and life threatening hyperthermia. I now constantly overheat everyday and have a list of symptoms one of them being a severe chemical sensitivity.

I can no longer use use any sort of recreational drugs as even the smallest dose has the potential to be fatal for me due to my neurological condition. Ive had severe adverse reactions to morphine, oxycodone tramadol, darvocet and codene that were given to me by my Dr's to treat my pain. But after a surgery last year they discovered that they were able to use fentanyl with me without any problems so based on that and a follow up iv fentanyl test Ive now been given 12 micrograms an hour patches. So even thou my Dr thinks its fine im still kinda scared to start on them, what do you guys think for someone witha chemical sensitivity and no opiod tolerance are 12mcg patches usualy safe to start on?