In addition to the general indications for all members of the tetracycline antibiotics group, doxycycline is frequently used to treat Lyme disease, chronic prostatitis, sinusitis, pelvic inflammatory disease, acne, rosacea, and rickettsial infections.
It is used in prophylaxis against malaria. It should not be used alone for initial treatment of malaria, even when the parasite is doxycycline-sensitive, because the antimalarial effect of doxycycline is delayed. This delay is related to its mechanism of action, which is to specifically impair the progeny of the apicoplast genes, resulting in their abnormal cell division.
Moraxella catarrhalis, Brucella melitensis, Chlamydia pneumoniae, and Mycoplasma pneumoniae are generally susceptible to doxycycline, while some Haemophilus spp., Mycoplasma hominis, and Pseudomonas aeruginosa have developed resistance to varying degrees.
It is used in the treatment and prophylaxis of anthrax (caused by Bacillus anthracis) and Leptospirosis. It is also effective against Yersinia pestis (the infectious agent of bubonic plague), and is prescribed for the treatment of Lyme disease, ehrlichiosis andRocky Mountain spotted fever. In fact, because doxycycline is one of the few medications shown to be effective in treating Rocky Mountain spotted fever (with the next-best alternative being chloramphenicol), doxycycline is indicated even for use in children for this illness. Otherwise, it is not indicated for use in children under the age of eight years.
- Rocky Mountain spotted fever, typhus fever and the typhus group, Q fever, rickettsialpox, and tick fevers caused by Rickettsia
- Respiratory tract infections caused by Mycoplasma pneumoniae
- Lymphogranuloma venereum, trachoma, inclusion conjunctivitis, and uncomplicated urethral, endocervical, or rectal infections in adults caused by Chlamydia trachomatis
- Psittacosis (ornithosis) caused by Chlamydia psittaci
- Nongonococcal urethritis caused by Ureaplasma urealyticum
- Relapsing fever due to Borrelia recurrentis
- Chancroid caused by Haemophilus ducreyi
- Plague due to Yersinia pestis
- Tularemia due to Francisella tularensis
- Cholera caused by Vibrio cholerae
- Campylobacter fetus infections
- Brucellosis caused by Brucella species (in conjunction with streptomycin)
- Bartonellosis caused by Bartonella bacilliformis
- Granuloma inguinale caused by Calymmatobacterium granulomatis
- Lyme disease caused by Borrelia burgdorferi
- Escherichia coli infections
- Enterobacter aerogenes (formerly Aerobacter aerogenes) infections
- Shigella species infections
- Acinetobacter species (formerly Mima species and Herellea species) infections
- Respiratory tract infections caused by Haemophilus influenzae
- Respiratory tract and urinary tract infections caused by Klebsiella species
Some Gram-positive bacteria have developed resistance to doxycycline. Up to 44% of Streptococcus pyogenes and up to 74% of S. faecalis specimens have developed resistance to the tetracycline group of antibiotics. When bacteriologic testing indicates appropriate susceptibility to the drug, doxycycline may be used to treat these infections caused by Gram-positive bacteria:
- Upper respiratory infections caused by Streptococcus pneumoniae (formerly Diplococcus pneumoniae)
- Skin and soft tissue infections caused by Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus infections
- Anthrax caused by Bacillus anthracis infection
- Syphilis caused by Treponema pallidum
- Yaws caused by Treponema pertenue
- Listeriosis due to Listeria monocytogenes
- Vincent’s infection caused by Fusobacterium fusiforme
- Actinomycosis caused by Actinomyces israelii
- Infections caused by Clostridium species.