My doctor advised me to take Zithromax 3 times a week, but I declined. I have a moderate case of CF and each time I'm on any antibiotic I get terrible thrush and yeast infections below which lasts for a month or two. On the same note, I had to also stop TOBI and Flovent for those reasons. Now, I don't take any antibiotic unless I have no other choice. I think all women with CF should be more careful with the usage of antibiotics. Not to mention, it's one more medication that your body can become resistant to. I'm now resistant to Cipro, Levaquin, and Bactrim. Zithromax is the last oral drug left. I wish I would have not "jumped the gun" to take antibiotics when I was in my teens. It messed me up.