I wonder if anyone can help, after returning from holiday I have terrible catarrh. I have it every time I fly, I think the air conditioning gets me. In the past I have taken a decongestant to dry it up, but since taking Levothyroxine I see you are advised not to take certain cold/cough remedies. I am ok during the latter part of the day but for a few hours after waking I am coughing badly trying to clear the back of my nose/throat. I have put Oubas oil on a handkerchief by my pillow and bought an inhaler too, when I lie down i cough and feel as though I'm choking.