500 mg is the metformin
used for the treatment of diabetes/pre diabetes. Is she diabetic? You have not mentioned why she is taking metformin( Glycomet)
GIT side effects in the form of nausea, vomiting
are a very common side effect form the use of glycomet.
Most of the time they settle down with in a few days of staring the medication, if they do not settle down you may need to contact the doctor to look for some other cause of the problem or to change the medication.
Hope it helps.