Doryx is a trade name for doxycycline, a member of the tetracycline antibiotic drug group. Doxycycline is active against a variety of bacteria. It is useful for treating a diverse array of infections from acne to the plague. Some bacteria have developed resistance to doxycycline, which has limited its use for some infections. Nonetheless, doxycycline remains a potent antibiotic with many important medical uses.
Rickettsial Infections
Rickettsiae are a group of bacteria most commonly contracted via the bite of an infected tick. The diseases caused by rickettsiae include epidemic typhus, murine typhus, rickettsialpox and Rocky Mountain spotted fever. The Centers for Disease Control and Prevention (CDC) recommends doxycycline as the antibiotic of choice for all tickborne rickettsial infections.
Walking Pneumonia
Walking pneumonia caused by the bacterium Mycoplasma pneumoniae is common in both adults and children. Doxycycline is active against this bacterium and can be used to treat the infection.
Chlamydia Infections
Three species of chlamydia bacteria cause human infections. The sexually transmitted disease (STD) chlamydia is caused by the bacterium Chlamydia trachomatis. CDC estimates approximately 2.3 million Americans have chlamydia. Chlamydia trachomatis also causes another STD, lymphogranuloma venereum. Other Chlamydia species cause psittacosis (a lung infection) and trachoma (an eye infection). Doxycycline is effective against all of these chlamydia infections.
Alternative Treatment of Syphilis
The antibiotic of choice for the treatment of syphilis is benzathine penicillin G. However, in people with severe penicillin allergy, doxycycline may be used as an alternative antibiotic treatment.
Plague
Once a killer of millions, plague is now an uncommon but still potentially lethal infection. The bacterium Yersinia pestis causes plague. Humans contract the disease from the bite of an infected flea. Wild rodents including rock squirrels, ground squirrels, chipmunks and prairie dogs may harbor the bacteria, which are passed to the fleas as they feed on the rodent's blood during a bite. When a person is bitten by an infected flea, plague bacteria travel through the blood stream eventually infecting the lungs and causing pneumonia. Once the plague bacteria are in the lungs, the disease can spread from person to person by coughing. Although doxycycline is not the drug of choice for the treatment of plague, it is effective against plague-causing bacteria and can be used for this infection.
Cholera
Cholera is a severe diarrheal illness caused by the bacterium Vibrio cholera. The illness is contracted by eating food or drinking water contaminated with cholera bacteria. Cholera is rare in the United States. Doxycycline is an effective antibiotic for the treatment of cholera.
Acne
Acne vulgaris--better known as acne--affects most people at different times of life. Acne ranges from mild to severe, with the severe form potentially causing permanent scarring and disfigurement. The bacterium Propionibacterium acnes is one of several contributing factors in the development of acne. In people with severe acne, doxycycline may to used to control the growth of Propionibacterium acnes on the skin. Antibiotic therapy combined with topical treatments can reduce the severity and frequency of acne outbreaks.
References
- Drugs.com: Doxycycline FDA Information
- Todar's Online Textbook of Bacteriology: Rickettsial Diseases
- Centers for Disease Control and Prevention, MMWR: Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever, Ehrlichioses, and Anaplasmosis --- United States
- Medline Plus: Mycoplamsa pneumonia
- University of South Carolina School of Medicine, Microbiology and Immunology Online: Chlamydia
