DOXYLIN

What it is

DOXYLIN is a film coated tablet containing doxycycline hyclate equivalent to either 50 mg or 100 mg of doxycycline.

Approved indications

— Primary atypical pneumonia caused by Mycoplasma pneumoniae — Queensland tick typhus, epidemic typhus fever, Q fever, murine endemic typhus fever and Australo-Pacific endemic scrub typhus caused by Rickettsiae — Psittacosis caused by Chlamydia psittaci — Granuloma inguinale caused by Calymmatobacterium (Donovania) granulomatis — Lymphogranuloma venereum, trachoma and inclusion conjunctivitis caused by Chlamydia trachomatis — Cholera caused by Vibrio species — Brucellosis caused by Brucella species (in conjunction with streptomycin) — Plague caused by Yersinia pestis — Tularaemia caused by Francisella tularensis — Bartonellosis caused by Bartonella bacilliformis — Infections caused by Bacteroides species — Malaria chemoprophylaxis caused by Plasmodium falciparum in adults and children older than 10 years — Malaria caused by Plasmodium vivax in combination with other antimalarial agents in adults and children older than 10 years — Syphilis caused by Treponema pallidum when penicillin is contraindicated — Yaws caused by Treponema pertenue when penicillin is contraindicated — Gonorrhoea caused by Neisseria gonorrhoeae when penicillin is contraindicated — Acute intestinal amoebiasis as a useful adjunct to amoebicides — Severe acne as adjunctive therapy

Dosing overview

For adults and children over 8 years and above 50 kg in weight, the usual dose is 200 mg on the first day of treatment (100 mg every 12 hours) followed by a maintenance dose of 100 mg per day, which may be administered as a single dose or as 50 mg every 12 hours. In the management of more severe infections, particularly chronic infections of the urinary tract, 100 mg every 12 hours is recommended. For acute uncomplicated gonococcal infections, 100 mg twice daily for 5 to 7 days is recommended. For primary and secondary syphilis, 300 mg a day in divided doses for at least 10 days is recommended. For louse-borne typhus, a single oral dose of 100 mg or 200 mg according to severity has been used; for prevention of scrub typhus, 200 mg as a single dose. For severe acne, some efficacy has been demonstrated at a dose of 50 mg per day over a period of 12 weeks. For malaria chemoprophylaxis, 100 mg once daily is recommended, commencing two days prior to entering malarious areas, while in the malarious area and for four weeks after leaving the malarious area, with a maximum of 100 mg daily for 8 weeks. For children over 8 years of age and below 50 kg in weight without skeletal growth retardation, the adult dose of 100 mg should be recalculated on a weight basis of 2 mg per kilogram.

Key safety warnings

Photosensitivity manifested by an exaggerated sunburn reaction has been observed in some individuals taking tetracyclines. Patients should be advised against exposure to direct sunlight or ultra-violet light, and treatment should be discontinued at the first sign of skin erythema. Severe skin reactions, such as exfoliative dermatitis, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis and drug reaction with eosinophilia and systemic symptoms (DRESS), have been reported in patients receiving doxycycline. Fixed drug eruptions have occurred and have been associated with worsening severity upon subsequent administrations. If severe skin reactions occur, DOXYLIN should be discontinued immediately. Intracranial hypertension (IH) has been associated with the use of tetracyclines including doxycycline. Women of childbearing age who are overweight or have a history of IH are at greater risk for developing tetracycline associated IH. Clinical manifestations include headache, blurred vision, diplopia and vision loss. Although intracranial hypertension typically resolves after discontinuation of treatment, the possibility for permanent visual loss exists. If visual disturbance occurs during treatment, prompt ophthalmologic evaluation is warranted. Clostridium difficile associated diarrhoea (CDAD) and antibiotic associated pseudomembranous colitis have been reported with nearly all antibacterial agents including doxycycline and may range in severity from mild diarrhoea to fatal colitis. If doxycycline is ingested in an incorrect manner there is a risk of adhesion of the tablet to the oesophagus, which may cause oesophageal injury. In order to avoid oesophageal injury, doxycycline must be ingested with at least 100 mL of fluid and the patient must remain upright for at least 30 minutes.

Contraindications

DOXYLIN is contraindicated in patients with hypersensitivity to doxycycline, any of the excipients in DOXYLIN or to any of the tetracyclines. Use in pregnancy (16 weeks post conception) and use in lactation are contraindicated. Concomitant treatment with oral retinoids, such as isotretinoin or etretinate, and vitamin A is contraindicated due to rare cases of benign intracranial hypertension reported after tetracyclines and these agents. The concurrent use of tetracycline and methoxyflurane has been reported to result in fatal renal toxicity.

Regulatory history

DOXYLIN 50 (AUST R 63511) and DOXYLIN 100 (AUST R 63509) were first registered on 22 May 1998.