Hi, I'm a 17 y/o female with CF and I just finished up with a months course of amikacin and cefepime, intervenously. Then when my period showed up, it was extremely light and only lasted a few days. Do any of you girls out there know if this is normal or have had this same problem. I'm wondering if the antibiotics can throw your system out of wack like that.If anybody has any info, please reply. Thanks