Metronidazole
"This is the 3rd course of metronidazole I've taken in the last year for BV and I will never take this medication again!  The first 2 times I had the normal side effects of headache, fatigue and metallic taste.  This 3rd time has been an absolute nightmare! Around day 4 was when I started to get heart palpitations, flu-like symptoms, muscle aches, tiredness and chills.  I literally thought I was going to die a couple times.  I had to go to the ER because I almost passed out.  They did a full work-up with labs and an EKG and found nothing wrong.  I've stopped the medication 5 days ago and my symptoms are getting worse.  I'm not sure how long it will take for this medication to get out of my system, but I hope it is soon!"