A tetracycline antibiotic, it is used (mainly as the hydrochloride) for the treatment of Lyme disease, acne and bronchitis, as well as for hyponatraemia (low blood sodium concentration) due to the syndrome of inappropriate antidiuretic hormone (SIADH) where fluid restriction alone has been ineffective. It has a role as an antibacterial drug and an aquaretic. It contains a demeclocycline.