For Contued Low Blood Pressure My Husband Is On Fludrocortosone

For contued low blood pressure my husband is on fludrocortosone as well as azrithromyacon and am wondering about a drug interaction pressure is now 60 over 40. He is a parkinsons patient andd takes leva dopa carb. dopa as well as mididrine. He has to have azithromycin for a lung , asperation caused constant cough otherwise. the fludrocortisone was introduced recently by a neuphrology physician (3rd stage kid failure) and wonder if this cortosone is interacting with his other drugs?? Bear with me,at 90 yrs I am trying hard at everything.