This leads to an accumulation of the skins natural oils and bacteria (Propionibacterium acnes) in the skin (which feed on the oils and keratin) which further inflame the gland causing acne.
It is recommended that you tell your physicians to avoid drugs that end in mycin ( Azithromycin, Erythromycin ) because of possible reactions which could lead to setbacks.
Scientists at Chugai discovered an erythromycin-derived motilin agonist called Mitemcinal (aka GM-611 or 3'-N-dimethyl-11-deoxy-3'-N-isopropyl-12-O-methyl-11-oxo-8,9-didehydroerythromycin.) Mitemcinal was believed to have strong prokinetic properties, similar to its parent molecule, but lack antibiotic properties.