Metronidazole
"I had an intestinal parasite after a trip to Central America. I had a very difficult time in this drug. I'm a healthy, 40 year old woman and the side effects put out for the 5 days I was only this pill. I was taking 750mg every 8 hours for 10 days. I called my doctor and had to stop after 5 days. Severe headaches, nausea, weak, fatigue. I couldn't work and had to rest all day. Metallic taste as well. I would not take this drug again- I would ask for another treatment. It's an aggressive drug that was difficult to tolerate."