Hello
Metronidazole or metrogyl is an antiamoebics drug. 
Dosage are: 400 -800 mg thrice in  a day , depending on the type of disease and symptoms .
Prescribed in 
amoebiasis , balantidiasis , blastocystitis hominis, 
giardiasis , parasites .
Side effects are nausea, vomiting, abdominal cramps , diarrhea, 
constipation, furred tongue , glossitis somatitis due to overgrowth of candida, 
dizziness , ataxia.
As these are common side effects but in comparison of benefit , you can take it . 
Since most common side  effects are nausea , dizziness , so you can take pnataprazole-d once or twice in day 2 hours before or after this drug.
Take this drug as advised your physician.
Hope this will help you.