How do you know when you need IV antibiotics?

I have posted here before about my two sons getting diagnosed in their teens a few years ago. Because we did not go through the normal learning curve with CF, there is some basic knowledge that we do not have. This is one of these instances. My older son, age 20 is having an exacerbation. He has never been hospitalized (for anything, let alone CF). He has been on cipro over 3 days with no positive effect yet. He is using his vest 3 hours a day, and is coughing too much to sleep at night. When we called the doctor, he said all we can do now is take him to the ER if we want to. My question is -- what is bad enough to go to the ER? The doctor really didn't give me a straight answer on this. Also if he does go there, will he be admitted for IV antibiotics, or do they do some tests to determine if he needs to stay? How long is a typical course of IV antibiotics? Final question -- he is not on TOBI and I found out tonight that he cultures pseudomonas. Is TOBI something that can be prescribed over the phone? Would it help in an exacerbation? Thanks in advance you folks are so very helpful.
Source: Cystic Fibrosis Adults Forum - Category: Respiratory Medicine Authors: Tags: Adults Source Type: forums