<unk> , like other tetracyclines, is used to treat many infections, both common and rare (see Tetracycline antibiotics group). Its better absorption profile makes it preferable to tetracycline for moderately severe acne at a dosage of 250–500 mg four times a day for usually six to eight weeks at a time, but alternatives should be sought if no improvement occurs by three months. It is sometimes used to treat spirochaetal infections, clostridial wound infection and anthrax in patients sensitive to penicillin.<unk>  is used to treat infections of the respiratory and urinary tracts, skin, ear, eye and gonorrhoea, although its use for such purposes has declined in recent years due to large increases in bacterial resistance to this class of drugs. The drug is particularly useful when penicillins and/or macrolides cannot be used due to allergy. It may be used to treat Legionnaire's disease as a substitute for a macrolide or quinolone.<unk>  is especially valuable in treating nonspecific urethritis, Lyme disease, brucellosis, cholera, typhus, tularaemia. and infections caused by Chlamydia, Mycoplasma and Rickettsia. Doxycycline is now preferred to<unk>  for many of these indications because it has improved pharmacologic features. The standard dose is 250–500 mg six-hourly by mouth. In particularly severe infections, this dose may be increased accordingly. Occasionally,<unk>  is given by intramuscular injection or topically in the form of creams, ophthalmic ointments or eye drops.
Oxytetracycline
Chlortetracycline
Doxycycline
Eravacycline
Sarecycline
Tetracycline
Streptomycin
Minocycline