I was prescribed Amitriptyline for nerve damage in the 90's near the end of a long hospital stay & just got out the diary I kept during and a little while after being in hospital (& am regretting typing out the Amitriptyline exerts now rather than just summarising it in a sentence, sorry)
TLDR!!
'On Monday, because I still have the burning nerve pain in my foot, they said they'd put me on a new pill and take me off the DF's as they were worried about me getting addicted to them, as I'd been having them for six weeks.
It was really busy that night so the pills didn't come round til midnight, by which time my foot was hurting really badly, so I was hoping this new pill, Amitriptyline would work, but I was just waking up all night in loads of pain, then saw the doctor the next morning about 10 & burst into tears cos my foot was still hurting & she said the Amitriptyline takes 2 weeks to start working (It's actually an anti-depressant, but apparently it's good for nerve damage as well. I wonder if it'll make me extra happy as I wasn't depressed to start off with - the side effects can be dry mouth and palpitations though, which sounds a bit dodgy)
I said I was in loads of pain so she put me back on the DFs again as it was a bit silly taking me off them when the new one won't work for 2 weeks.......................
..................The anti-depressants for my nerve pain should start working soon as it's exactly 2 weeks since I started them. Maybe I've got them to thank for the lightening of my mood today. I ended up taking 4 DFs last night cos I was so bored and devil-may-care (the 1st 2) then wide awake (the 2nd 2) It does seem that my foot doesn't hurt so much if I've taken 4 Dfs the night before. My 'coming off DFs' plan isn't going very successfully'
I lost the will to live just copying that bit out & don't seem to mention the Amitriptyline again in the few months I kept the diary after I left hospital & have no memory of whether it was effective or not, but I imagine the increased use of heroin probably confused matters. I do know I didn't experience any side-effects from it, whereas when an elderly relative was prescribed it (for nerve pain), he stopped taking it as it was making him hallucinate & 'feel weird' and a friend found it over-sedated him all the time
I hope your lady finds something effective to relieve the pain - that horrible twanging, burning sciatic pain is a shocker and glad she's got a supportive, helpful Fubar on the case