What Is The Correct Dosage Of Cesestamine NS For Skin Rash?

What is the correct dosage of Cesestamine NS (I am taking it for a skin rash -- which occurs when I am out in the sun and use a sunscreen on my arms. (I have a cream also). I have taken it before (in Mexico) and it works, but can't remember the dosage and it is not on the package.

Thanks.