... back full force. While on the 10 mg, I experienced no side affects at all, except for nauseousness and dizziness the first day I took it. I was prescribed 20 mg and I began to start taking it yesterday. Today I am experiencing a slight pain in my head and I noticed blood after I went number 2 and I was constipated as well. Is this due to the increase in mg or could it possibly be something else?