Doxycycline has a very wide spectrum of activities and has been used in the treatment of a large number of infections caused by susceptible organisms. Respiratory tract infections: Pneumonia, influenza, pharyngitis, tonsillitis, bronchitis, sinusitis, otitis media and other streptococcal and staphylococcal infections where tetracycline resistance is not a problem. Genitourinary tract infections: Pyelonephritis, cystitis, urethritis, gonorrhea, epididymitis, syphilis, chancroid and granuloma inguinale. Chlamydia: Lymphogranuloma venereum, psittacosis, trachoma. Intestinal diseases: Whipples disease, tropical sprue, blind loop syndrome. In acute intestinal amoebiasis: Doxycycline may be a useful adjunct to amoebicides. Bacillary infections: Brucellosis, tularemia, cholera, travelers diarrhea Acne: Acne vulgaris, acne conglobata and other forms of acne. Other infections: Actinomycosis, yaws, relapsing fever, leptospirosis, typhus, rickettsial pox and Q fever, Cellulitis furunculosis, abscess and infections caused by Mycobacterium marinum, Bordetella pertussis and Bacillus anthracis.
Tetracycline Group of drugs
Doxycycline Hydrochloride is a semisynthetic tetracycline antibiotic with broad spectrum activity. It is primarily a bacteriostatic antibiotic. It has a similar spectrum of activity to other tetracyclines but in particular is more active against Staphylococcus aureus and Nocardia. The drug is often active against penicillin-resistant strains of Staphylococcus aureus and against strains of those organisms that are resistant to other Tetracyclines. Certain Gram-negative strains of E. coli, Proteus mirabilis and Klebsiella, which are often resistant to Tetracycline, may be sensitive to Doxycycline. In addition, 70-90% of the various anaerobes are sensitive to Doxycycline and Bacteroides fragilis is more likely to be sensitive to Doxycycline than to other tetracyclines.
Doxycycline is active against most strains of Haemophilus influenzaeand is particularly useful for infections with H. ducreyi, Actinomyces, Brucella and Vibrio cholerae. It is also active against Nocardia, Chlamydia, Mycoplasma and a wide range of Rickettsiae. Doxycycline is active against spirochetes such as Borellia recurrentis, Treponema pallidum and Treponema pertenue. It is also active against Plasmodium falciparum.
Oral- Susceptible infections: 200 mg on day 1 as a single or in divided doses, followed by 100 mg once daily. Severe infections: Maintain initial dose throughout the course of treatment. Relapsing fever and louse-borne typhus: 100 or 200 mg as a single dose. Prophylaxis of scrub typhus: 200 mg as a single dose. Uncomplicated gonorrhoea: 100 mg bid for 7 days or a single dose of 300 mg followed by a 2nd similar dose 1 hr later. Syphilis: 100-200 mg bid for at least 14 days. Acne: 50 mg daily for 6-12 wk. Chloroquine resistant falciparum malaria acute attack: 200 mg daily for at least 7 days, w/ or after treatment w/ quinine. Treatment and postexposure prophylaxis of inhalation anthrax: 100 mg bid, to complete a 60-day course after treatment w/ 1-2 other antibacterials. Prophylaxis of chloroquine-resistant malaria: 100 mg daily for up to 2 yr. Topical/Cutaneous- Periodontitis: As 10% controlled-release subgingival preparation: Inject the contents of the syringe into the periodontal pocket, may be repeated 4 mth after initial treatment. Intravenous- Susceptible infections: 200 mg on day 1 followed by 100-200 mg daily depending on the severity of infection.
Absorption of tetracyclines is impaired by antacid containing aluminium, calcium or magnesium, and iron containing preparation. Absorption of tetracyclines is also impaired by bismuth salicylate. Barbiturates, carbamazepine and phenytoin decrease half-life of doxycycline. Concurrent use of tetracyclines may render oral contraceptive less effective. Patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosages. It is advisable to avoid giving tetracyclines in conjunction with penicillin.
Hypersensitivity to doxycycline and any of the tetracyclines. Concurrent use with methoxyflurane. Lactation During development of teeth (last trimester of pregnency, upto 12 yrs of age) the use of tetracyclines may lead to discoloration of teeth. So tetracyclines should not be administered during these periods
Gastrointestinal disterbances,eg. anorexia, vomiting, dysentry etc. overgrowth of resistant organisms may cause Glossitis, Stomatitis, or Staphylococcal enterocolitis; Apart from these skin rashes, purpura may occur. Photosensitivity and dermatological reactions are rare.
Pregnancy: Doxycycline should be avoided in pregnant women, because of the risk of both staining and effect on bone growth in the fetus. Lactation: Doxycyclines enter breast milk, and mothers taking these drugs should not breastfeed their child.
Keep all medicines out of reach of children. Store in a cool and dry place, protected from light.
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