@maryb,
About 6 mths. ago, I could only take ~100 mgs. of metronidazole (flagyl), for 2 days.
Then, about 4mths. ago, I tried again, and was able to take about 250 mgs. for 4-5 days.
In between, I took short courses, low dose, of some other abx. ( I believe they may have lowered some of the pathogens, especially in the gut.) All had strong side effects, but with some improvements, including neurological.
This last time, I was able to tolerate the metro. for 6 days at 500 mgs. in divided doses. (2)
I did have mild neuritis, nausea, insomnia, and moods. Headaches too.(herx)
( I take hydrocortisone, and increasing it helped some of the side effects, or herx?)
All of the antibiotics I've tried seem to lower hormones, sex hormones included.
The metro. has been more effective to my head than the others; including sinuses , mouth, ears, throat, and meninges (?). Migraines are gone for now. Haven't had Vertigo in 2 mths.
...still take extra B12 and choline...may lower doses in the future.
It's mighty strong, but, my energy is so much better...I'll take it again if the need arises.