How do you approach use of Doxy PEP in a patient taking isotretinoin, as both drugs are (rarely) associated with pseudotumor cerebri, which is very uncommon in clinical practice?

I do not use doxycycline in almost all circumstances if a patient is on isotretinoin. That would certainly include using it as post-exposure prophylaxis (PEP). An exception to this combination would be treating a life-threatening disease such as Rocky Mountain spotted fever. Of course, a health care...