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 infectionWhen penicillin is contraindicated, doxycycline can be used to treat:
Syphilis caused by Treponema pallidum
Yaws caused by Treponema pertenue
Listeriosis due to Listeria monocytogenes
Vincents infection caused by Fusobacterium fusiforme
Actinomycosis caused by Actinomyces israelii
Infections caused by Clostridium speciesDoxycycline may also be used as adjunctive therapy for severe acne.The first-line treatment for brucellosis is a combination of doxycycline and streptomycin and the second-line is a combination of doxycycline and rifampicin (rifampin). Antimalarial
Doxycycline is active against the erythrocytic stages of Plasmodium falciparum but not against the gametocytes of P. falciparum. It is used to prevent malaria. It is not recommended alone for initial treatment of malaria, even when the parasite is doxycycline-sensitive, because the antimalarial effect of doxycycline is delayed.The World Health Organization (WHO) guidelines state that the combination of doxycycline with either artesunate or quinine may be used for the treatment of uncomplicated malaria due to P. falciparum or following intravenous treatment of severe malaria. Antihelminthic
Doxycycline kills the symbiotic Wolbachia bacteria in the reproductive tracts of parasitic filarial nematodes, making the nematodes sterile, and thus reducing transmission of diseases such as onchocerciasis and elephantiasis. Field trials in 2005 showed an eight-week course of doxycycline almost eliminates the release of microfilariae.
The best available evidence indicates that doxycycline has little or no effect on hypoplasia of dental enamel or on staining of teeth and the CDC recommends the use of doxycycline for treatment of Q fever and also for tick-borne rickettsial diseases in young children and others advocate for its use in malaria. Other
Other contraindications are severe liver disease and concomitant use of isotretinoin or other retinoids, as both tetracyclines and retinoids can cause intracranial hypertension (increased pressure around the brain) in rare cases. Adverse effects
Adverse effects are similar to those of other members of the tetracycline antibiotic group. Doxycycline can cause gastrointestinal upset. Oral doxycycline can cause pill esophagitis, particularly when it is swallowed without adequate fluid, or by persons with difficulty swallowing or impaired mobility. Doxycycline is less likely than other antibiotic drugs to cause Clostridium difficile colitis. An erythematous rash in sun-exposed parts of the body has been reported to occur in 7.3–21.2% of persons taking doxycycline for malaria prophylaxis. One study examined the tolerability of various malaria prophylactic regimens and found doxycycline did not cause a significantly higher percentage of all skin events (photosensitivity not specified) when compared with other antimalarials. The rash resolves upon discontinuation of the drug.Unlike some other members of the tetracycline group, it may be used in those with renal impairment.Doxycycline use has been associated with increased risk of inflammatory bowel disease. In one large retrospective study, patients who were prescribed doxycycline for their acne had a 2.25-fold greater risk of developing Crohns disease.