Spiramycin has no effect on serum theophylline in asthmatic patients.

Fifteen asthmatic patients receiving a sustained-release theophylline preparation were also treated with spiramycin for at least 5 days. The macrolide antibiotic had no significant effect on the steady-state theophylline concentration, unlike erythromycin and troleandomycin, which belong to the same class of antibiotics. The latter two drugs have different chemical structures and decrease theophylline clearance. Accordingly, spiramycin comedication does not require special serum level drug monitoring or adjustment of the dose of theophylline.