Patient mixed Diuril and alcoholic beverage, which resulted in syncope, described as an accident

This is one of my problems I have to code. I don't have any idea where to start. Can someone help me get on the right track?

I'm not asking anyone to do it for me.. just to help me get on the right way so I can figure it out. I don't know where to start coding it at.

Start with over-dose, accident and type of meds. Use syncope as a secondary dx.