我大致查了一下：

“Amoxicillin belongs to a group of antibiotics called Penicillins. If you are allergic to Penicillins then you are more likely to be allergic to a group of antibiotics called Cephalosporins of which Cephalexin is a member. Cephalexin should be avoided in a penicillin allergic patient. Antibiotics such as clarithromycin, doxycycline and erthyromycin may be safe alternatives for you.”

大家还是注意一下。特别是青霉素过敏的人。