 [ Symptoms ] my 9 yr old daughter has been extremely fatigued for 3 days now she is usually very energetic even sick any causes  she has been not feeling well since tuesday june 4 2013 he stmach is queasy but she is really lethargic and this is way out of her normal behavior doctor diagnosed her fatigued with no reason and did not perform any tests [ Disease ] in general metronidazole is very harsh on the stomach and can cause nausea vomiting and upset stomach it is recommended to take with food and to avoid alcohol which has a drug drug interaction will cause vomiting if you daughter is pregnant i would not take this medication and would seek advice from your doctor as to why or if another medication can be prescribed have your daughter in law contact her ob gyn to see if heshe feels safe with her taking this medication also ask your ob gyn if they have a list of medications that they believe are safe to take during pregnancy