Hi Prekshit Mehta,
Thanks for writing your query.
It is good that you are following strict diet control for your diabetes
Your symptoms of giddiness can be due to hypoglycemia
that is low blood sugar
. You should discuss with your treating doctor for adjusting the dose of the medicine or change in medicine. Istamet contains two compounds Sitagliptin
50 mg and Metformin
If you are having frequent hypoglycemia, you can be given only Metformin, (if your doctor thinks it will be good for you). Follow your treating doctor's advice as he has examined you medically and knows more about your condition. So he can be a better judge.
Whenever you feel giddiness, you should eat or drink some sweet preparation as low blood sugar level is more dangerous.
I hope this is helpful to you.