I echo what CA said.
You could try the Tinnidazole and see how you fare.
Also wanted to ask - was your reaction possibly a herx? In that case, starting low and increasing may work.
...or is it an allergy?
I don't know but after my second dose of the day which were both low doses I got what felt almost like chest pain for over 12 hours, it felt uncomfortable to even sit down and I waited out into the next day until I could finally be comfortable to go to sleep.