This product is a peripheral antitussive drug, which exerts its antitussive effect by selectively inhibiting the peripheral C-fibers of the trachea and bronchus. Its site of action is at the site associated with sensory neuropeptides after the peripheral junction. It has a strong antitussive effect and lasts for a long time. Since it has no effect on β-adrenergic receptors, M-cholinergic receptors and opioid receptors, it has fewer adverse reactions of central inhibition and is an efficient and safe antitussive drug.

It has a good antibacterial effect on human tuberculosis bacteria, and its bactericidal effect is strongest at pH 5-5.5. It is currently the best bactericidal drug for tuberculosis bacteria that grow slowly in phagocytes in an acidic environment. The antibacterial concentration in vivo is 12.5 mu; g/ml, and 50 mu; g/ml can kill tuberculosis bacteria. The concentration that inhibits tuberculosis bacteria inside cells is 10 times lower than that outside cells, and it has almost no antibacterial effect in neutral and alkaline environments. The mechanism of action may be related to pyrazinoic acid. After pyrazinamide penetrates into phagocytes and enters the tuberculosis bacteria, the amidase in the bacteria removes the amide group and converts it into pyrazinoic acid to exert an antibacterial effect. In addition, because pyrazinamide is similar to nicotinamide in chemical structure, it interferes with dehydrogenase by replacing nicotinamide, prevents dehydrogenation, and hinders the use of oxygen by tuberculosis bacteria, which affects the normal metabolism of bacteria and causes death.

Dirithromycin is a macrolide antibiotic that inhibits protein synthesis by binding to the 50S ribosomal subunit of sensitive microorganisms. It is active against aerobic Gram-positive microorganisms (such as Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes), aerobic Gram-negative microorganisms (such as Haemophilus influenzae, Legionella pneumophila, Moraxella catarrhalis) and other microorganisms (such as Mycoplasma pneumoniae). In vitro tests also show that it is active against Listeria monocytogenes, Staphylococcus (C.F.G group), Bordetella pertussis, Propionibacterium acnes, etc., but the clinical significance is not yet fully understood. Bacteria resistant to other macrolide antibiotics are also resistant to this product.