when do you know when to stop flaygl

My 98 year old Mom was dx 6 weeks ago with c.diff after urinery infection  in Miami  put on 1000 mg vancom daily  and after 6 days had rash over whole body...doctor stopped med and then 3 days later got c.diff again...now on flagyl for 17 days  and tapering off for 1 wk 2 pills and now last week 1 pill.....but she continues to have 3 to 5 bms a day no diarreah (diarrhea) but loose stools....I am worried that the loose stools says she still has the infection and in a few days will be off flagyl....is this normal to have these loose stools for so long or does it mean that she still has the infection?
Mom is very weak and has a round stomach like a basketball....just started align   Thanks

[Ratnakar Kini, MD]

Hi,
Tapering of metronidazole (Flagyl) is usually not done. It is given for 14 days and stopped.
Improvement may be seen as early 2-4 days after starting the treatment.
If there is no response it may indicate resistnace to metronidazole.
Discuss with her doctor about taking probiotics along with Flagyl.