Is adco-contromet tablet safe to use for an early stage of pregnancy for nausea and vomiting?

You need to talk this over with your doctor. It has been used but there are no studies to reveal its safety. It would only be given if the benefits outweigh any risks.
The active ingredient in Contromet is metoclopramide.
Here is a link for you.
https://www.drugs.com/pregnancy/metoclopramide.html