Metronidazole
"I rated this a 5 because of the side effects, I am 22 years old , 5'4 and 160 pounds. I am taking 500mg twice a day and I'm only on my second day and I feel absolutely horrible. I'm incredibly fatigued , nauseous and moody , and the metallic taste in my mouth is driving me nuts all day. I can barely function at work, let alone move because I feel so weak. The odor and itch has cleared within two days which is great but this specific medication is very strong, I have taken several types of antibiotics before ( amoxicillin, penicillin, clindamycin, Bactrim) and I've never experienced side effects this bad. I can definitely say that it doesn't matter whether you're a skinny person or overweight, this medication is just very aggressive."