Is Erythromycin A Generic Alternative To Zithromax?

Is Erythromycin 250 MG tablets-1 a day for 10 days. the generic for Zithromax? Would be used for respiratory problems/sinus? When asked for a refill of Zithromax -6 tablets. 2 taken first day and then 1 each day for three days. This is what he wrote for me.