Where can you get better Dirithromycin

Where can you get better Dirithromycin? For erythromycin, you may not know a lot of people, but here's the introduction to it:

Erythromycin, tonsillitis caused by clinical mainly used in streptococcus, scarlet fever, diphtheria and carrier, gonorrhea, listeria disease, streptococcus pneumoniae lower respiratory tract infection (above applies to patients is not resistant to penicillin for legionella pneumonia and mycoplasma pneumonia, this product can be used as the preferred drug application. Can be applied to the upper respiratory tract infection caused by influenza bacillus and staphylococcus aureus skin and soft tissue infection, syphilis, and intestinal amebiasis.