I remember long time ago, a friend told me she was worry because her cat was on antibiotics for a very long time. I didnâ€[emoji]8482[/emoji]t ask why she was worry about the antibiotic. We just got back from the vet and Andy was given Zenequin for 4 more days, for a Brown Recluse Spider bite. He was given Zenequin for 21 days for a urinary infection and before he was done with those, a spider bit him. So he has been on the antibiotic for 27 days today. Whatâ€[emoji]8482[/emoji]s so bad about taking antibiotics for a long time?