I have been told my last sputum cultures shows a new strain of pseudomonas that is resistant to the tobi/tobramyacin that I have used over the years. I am now to start alternating my Tobi with Colistin. My doctor who is now on vacation called into the office social worker to have her check on me before I start it & to have me begin with 1/2 vial per dose for 1 weeks to see if I have any problems before dusing the prescriped 1 vial per dose. Besides it not being user friendly (having to mix it before use) & the frothiness of it......has anyone had any reactions to it? Even my pharmacy addressed the potential side affects. Mainly because my friend works there & keeps up to date on the new meds I go on. Now I am a little nervous about what to expect.