Macrolide antibiotics, such as erythromycin, clarithromycin and roxithromycin, have proven to be an effective long-term treatment for DPB.^[1][2] The successful results of macrolides in DPB and similar lung diseases stems from controlling symptoms through immunomodulation (adjusting the immune response),^[2] with the added benefit of low-dose requirements.^[1]

With macrolide therapy in DPB, great reduction in bronchiolar inflammation and damage is achieved through suppression of not only neutrophil granulocyte proliferation, but also lymphocyte activity and obstructive mucus and sputum secretions in airways.^[1] The antimicrobial and antibiotic effects of macrolides, however, are not believed to be involved in their beneficial effects toward treating DPB.^[3] This is evident, as the treatment dosage is much too low to fight infection, and in DPB cases with the occurrence of macrolide-resistant pseudomonas aeruginosa, macrolide therapy still produces substantial anti-inflammatory results.^[1]

Advanced cases of DPB, where severely excessive sputum production resistant to macrolides persists, additional therapy with the inhalant tiotropium has been shown to ease these symptoms and the related shortness of breath.^[4]