Tetracyclines are used to treat many gram-positive and gram-negative bacteria. They are also effective on some protozoa. In other words they are used against a large variety of infections. (Todar K.T 2009). However due to the issue of bacterial resistance, these antibiotics have significantly decreased in value. (Speer et al.1992).
Tetracyclines are mainly used as a treatment for acne, eye infections, pneumonia, gonorrhea, Rocky Mountain spotted fever, urinary tract infections and Lyme disease. (Ogbru and Marks 2008). Other bacterial infections which usually result in the prescription of tetracyclines include Chlamydia, rickettsia, brucella and the spirochaeta. As well as the previously mentioned, there are many other infections in which tetracyclines are administered since it is such a broad spectrum antibiotic.
Tetracyclines, for example Tetracycline hydrochloride, Demeclocycline hydrochloride, Doxycycline, Lymecycline, Oxytetracycline, Tigecycline are essentially able to treat the same infections. Minocycline, another member of the tetracycline family, has a broader spectrum; it is active against Neisseria Meningitidis as well as the infections treated by the other tetracyclines.
Tetracyclines have similar side effects but each individual drug does come with some added ones. These include nausea, vomiting, diarrhoea, dysphagia (difficulty in swallowing), and oesophageal irritation. Other rare side effects have been noted such as acute renal failure and skin discolouration. (Joint Formulary Committee 2007, British Medical Association and Royal Pharmaceutical Society of Great Britain2008).
The dosages of tetracyclines i.e. when taken orally are usually 250mg, every 6 hours. This should be increased in severe infections to 500mg every 6-8hours. However this dosage does not apply to the different types of tetracyclines; each specific tetracycline has a specific dosage according to its strength. (Joint Formulary Committee 2007, British Medical Association and Royal Pharmaceutical Society of Great Britain 2008).
四环素类药物是用于治疗革兰氏阳性菌和革兰氏阴性菌。他们也有一些原生动物。换句话说，它们是用来对付各种各样的感染的。（Todar K. 2009）。然而，由于细菌耐药性的问题，这些抗生素有显着下降的价值。（Speer等人，1992）。