My question is regarding a medicine called xenical. This medication hinders the absorption of fats 30% found in food. These fats come with the stool or sometimes in form of fatty drops from the anus.
Are these drops considered Najasah and if they come to the underwear or on the body and not washed do they need to make Wudu or they are Taaher not Najasah?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

These drops that come out from the anus are impure whether they come with the stools or on their own. They are impure because they come out from where impurity comes out, and the ablution is invalidated when they come out.

Al-Bujayrimi one of the jurists of the Shaafi'ee school said: 'Any fluid [drops] that comes out from the private parts is impure.' Therefore, these drops are impure and it is an obligation to wash the body or the clothes that are stained by them. 

Allaah knows best.