Hi Terry @windwalker, Yikes! Don't you hate those what to do questions? Sorry to hear that your persistent cough came back. Dumb question from me but does the mucous that comes up with the cough seem similar (color, etc.) to what it was before you went on your tobramycin? Are you able to ask you doctor for advice on whether to use the antibiotic or go back to your tobramycin? I inherited my neighbors kitten when they found out their son was allergic to cats but he would break out in a rash where he hugged the cat. Hope the cough goes away quick!