Yes. Tetracyclines (e.g. Doxycycline), quinolones (e.g. Ciprofloxacin), macrolides (e.g. Clarithromycin), aminoglycosides (e.g. Gentamicin) and glycopeptides (e.g. Vancomycin) are all unrelated to penicillins and are safe to use in penicillin allergic subjects.
Yes. The bacteria must be sensitive to the drug.
Yes. If the infection is sensitive to the drug.
Was recently dx'd with lupus & am allergic to Keflex. Heard that lupus patients tend to have strong reactions to penicillin, should I avoid penicilin?
Avoid penicillin. I am not aware of the connection between allergy to PCN and lupus, You need to avoid PCN if you are allergic to keflex.