I have just started taking Factive and it is working wonders! I was diagnosed with chronic Lyme in June 2007 - have been on tons of meds and all different combos for past two years. The one co-infection we had not had much success in conquering was Bartonella - this was either due to my system not being able to tolerate the med or the med not being effective for me. So, my dr. has started to treat with Factive and prescribed it for me for the Bartonella.
As I am also on Bicillin injections, Plaquenil and Zithromax; he first suggested I go 5 days on Factive, 2 days off, 5 days on Zithro, 2 days off, etc. as you cannot take Factive and Zithro at same time.
However, my weeks on Factive are amazing and I'm hoping I can just stay on it. When I am on Factive I almost feel 100% again! Have had no herxs or side effects with Factive (but, this is me and everyone reacts differently to different meds - I've had reactions to other meds that were very rare.)
Hope this helps.