Hello
As you stated that you got
PARASITIC infection in Mexico , so advised 800 mg metroniazole three times in day .
Most probabaly you are feeling nausea,
dizziness , vomiting , abdominal discomfort ,
metallic taste in mouth , as these are common side effect.
So when such situation arise I prescribe
pantoprazole -D two times in day with
metronidazole as this will subside these side effects of metronidazole .
Also antacid help in this case.
Take these dosage after meal .
In my opinion the optimum dosage is important . If you take reduced dosage at your own will then resistance may develop ( for parasitic infection).
So get full advised dosages or consult your treating doctor and get his opinion .
Hope this will help you.