Rituxan and penicillin are not a class of drugs. The generic name of Rituxan is erythromycin, which is an antibacterial drug belonging to the macrolide class. Erythromycin can penetrate the cell membrane of bacteria and inhibit the synthesis of proteins in bacteria, and also inhibit the synthesis of bacterial ribosomes, thus playing a role in inhibiting the growth of bacteria. Therefore, erythromycin is a bacteriostatic agent and has bactericidal effect only at higher concentration for some specific bacterial species. Penicillin belongs to the β-lactam class of antibacterial drugs, penicillin into the bacteria can inhibit the synthesis of bacterial cell wall, the bacterial cell wall to produce holes or leakage caused by the leakage of important substances in the bacteria, so as to play a role in killing bacteria, so penicillin belongs to the bactericidal agent.