Hi Lizzie,
The non-convenia injectable ab’s that I know of are penicillin, clindamycin and I think baytril. It’s been quite awhile and I don’t remember which ones were once daily or if any of those were twice daily. I’m sure there must be other daily injectables out there. Idk which if any are the right fit for what Gizmo is on ab’s for or if there are potential interactions with Giz’s meds.
Not much help, I’m afraid, but I hope helps at least somewhat for when you talk to your vet.
As you know (and for readers unfamiliar with ab’s/probiotics) ab’s, whether injected, oral, daily or longer acting, are tough on the gut, so probiotics an essential during and after course of ab’s.