mydia trachomatis , although the infectious agent is not always eliminated as judged by immunofluorescence. inclusion conjunctivitis caused by chlamydia trachomatis . uncomplicated urethral, endocervical or rectal infections in adults caused by chlamydia trachomatis . nongonococcal urethritis caused by ureaplasma urealyticum . relapsing fever due to borrelia recurrentis . doxycycline tablets, usp are also indicated for the treatment of infections caused by the following gram-negative microorganisms: chancroid caused by haemophilus ducreyi . plague due to yersinia pestis . tularemia due to francisella tularensis . cholera caused by vibrio cholerae . campylobacter fetus infections caused by campylobacter fetus . brucellosis due to brucella species (in conjunction with streptomycin). bartonellosis due to bartonella bacilliformis . granuloma inguinale caused by klebsiella granulomatis . because many strains of the following groups of microorganisms have been shown to be resistant to doxycycline, culture and susceptibility testing are recommended. doxycycline tablets, usp are indicated for treatment of infections caused by the following gram-negative microorganisms, when bacteriologic testing indicates appropriate susceptibility to the drug: escherichia coli enterobacter aerogenes shigella species acinetobacter species respiratory tract infections caused by haemophilus influenzae . respiratory tract and urinary tract infections caused by klebsiella species. doxycycline tablets, usp are indicated for treatment of infections caused by the following gram-positive microorganisms when bacteriologic testing indicates appropriate susceptibility to the drug: upper respiratory infections caused by streptococcus pneumoniae . anthrax due to bacillus anthracis , including inhalational anthrax (post-exposure): to reduce the incidence or progression of disease following exposure to aerosolized bacillus anthracis . when penicillin is contraindicated, doxycycline is an alternative drug in the treatment of the following infections: uncomplicated gonorrhea caused by neisseria gonorrhoeae . syphilis caused by treponema pallidum subspecies pertenue . 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. in acute intestinal amebiasis, doxycycline may be a useful adjunct to amebicides. in severe acne, doxycycline may be useful adjunctive therapy.

e . c. difficile produces toxins a and b which contribute to the development of cdad. hypertoxin producing strains of c. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. cdad must be considered in all patients who present with diarrhea following antibiotic use. careful medical history is necessary since cdad has been reported to occur over two months after the administration of antibacterial agents. if cdad is suspected or confirmed, ongoing antibiotic use not directed against c. difficile may need to be discontinued. appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of c. difficile, and surgical evaluation should be instituted as clinically indicated. intracranial hypertension (ih, pseudotumor cerebri) has been associated with the use of tetracyclines including doxycycline tablets. clinical manifestations of ih include headache, blurred vision, diplopia, and vision loss; papilledema can be found on fundoscopy. women of childbearing age who are overweight or have a history of ih are at greater risk for developing tetracycline associated ih. concomitant use of isotretinoin and doxycycline tablets should be avoided because isotretinoin is also known to cause pseudotumor cerebri. although ih typically resolves after discontinuation of treatment, the possibility for permanent visual loss exists. if visual disturbance occurs during treatment, prompt ophthalmologic evaluation is warranted. since intracranial pressure can remain elevated for weeks after drug cessation patients should be monitored until they stabilize. all tetracyclines form a stable calcium complex in any bone-forming tissue. a decrease in the fibula growth rate has been observed in prematures given oral tetracycline in doses of 25 mg/kg every six hours. this reaction was shown to be reversible when the drug was discontinued. results of animal studies indicate that tetracyclines cross the placenta, are found in fetal tissues, and can have toxic effects on the developing fetus (often related to retardation of skeletal development). evidence of embryo toxicity has been noted in animals treated early in pregnancy. if any tetracycline is used during pregnancy or if the patient becomes pregnant while taking these drugs, the patient should be apprised of the potential hazard to the fetus. the antianabolic action of the tetracyclines may cause an increase in bun. studies to date indicate that this does not occur with the use of doxycycline in patients with impaired renal function. photosensitivity manifested by an exaggerated sunburn reaction has been observed in some individuals taking tetracyclines. patients apt to be exposed to direct sunlight or ultraviolet light should be advised that this reaction can occur with tetracycline drugs, and treatment should be discontinued at the first evidence of skin erythema.

less severe disease (greater than 8 years of age and weighing less than 45 kg), the recommended dosage schedule is 4.4 mg/kg of body weight divided into two doses on the first day of treatment, followed by a maintenance dose of 2.2 mg/kg of body weight (given as a single daily dose or divided into twice daily doses). for pediatric patients weighing over 45 kg, the usual adult dose should be used. the therapeutic antibacterial serum activity will usually persist for 24 hours following recommended dosage. when used in streptococcal infections, therapy should be continued for 10 days. administration of adequate amounts of fluid along with capsule and tablet forms of drugs in the tetracycline class is recommended to wash down the drugs and reduce the risk of esophageal irritation and ulceration (see adverse reactions ). if gastric irritation occurs, it is recommended that doxycycline be given with food or milk. the absorption of doxycycline is not markedly influenced by simultaneous ingestion of food or milk. studies to date have indicated that administration of doxycycline at the usual recommended doses does not lead to excessive accumulation of doxycycline in patients with renal impairment. uncomplicated gonococcal infections in adults (except anorectal infections in men): 100 mg, by mouth, twice a day for 7 days. as an alternate single visit dose, administer 300 mg stat followed in one hour by a second 300 mg dose. acute epididymo-orchitis caused by n. gonorrhoeae: 100 mg, by mouth, twice a day for at least 10 days. primary and secondary syphilis: 300 mg a day in divided doses for at least 10 days. uncomplicated urethral, endocervical, or rectal infection in adults caused by chlamydia trachomatis: 100 mg, by mouth, twice a day for at least 7 days. nongonococcal urethritis caused by c. trachomatis and u. urealyticum: 100 mg, by mouth, twice a day for at least 7 days. acute epididymo-orchitis caused by c. trachomatis: 100 mg, by mouth, twice a day for at least 10 days. inhalational anthrax (post-exposure): adults: 100 mg of doxycycline, by mouth, twice a day for 60 days. children: weighing less than 45 kg; 2.2 mg/kg of body weight, by mouth, twice a day for 60 days. children weighing 45 kg or more should receive the adult dose. when used in streptococcal infections, therapy should be continued for 10 days. administration of adequate amounts of fluid along with capsule and tablet forms of drugs in the tetracycline class is recommended to wash down the drugs and reduce the risk of esophageal irritation and ulceration. (see adverse reactions . ) if gastric irritation occurs, doxycycline may be given with food. ingestion of a high fat meal has been shown to delay the time to peak plasma concentrations by an average of one hour and 20 minutes. however, in the same study, food enhanced the average peak concentration by 7.5% and the area under the curve by 5.7%.

een reported but is uncommon. photosensitivity is discussed above. (see warnings .) renal toxicity: rise in bun has been reported and is apparently dose related. (see warnings .) hypersensitivity reactions: urticaria, angioneurotic edema, anaphylaxis, anaphylactoid purpura, serum sickness, pericarditis, and exacerbation of systemic lupus erythematosus. blood: hemolytic anemia, thrombocytopenia, neutropenia, and eosinophilia have been reported with tetracyclines. other: intracranial hypertension (ih, pseudotumor cerebri) has been associated with the use of tetracyclines. (see precautions – general .) when given over prolonged periods, tetracyclines have been reported to produce brown-black microscopic discoloration of the thyroid gland. no abnormalities of thyroid function are known to occur.

(0.19%) of the controls and 56 (0.30%) of the cases were treated with doxycycline.) this association was not seen when the analysis was confined to maternal treatment during the period of organogenesis (i.e., in the second and third months of gestation) with the exception of a marginal relationship with neural tube defect based on only two exposed cases. 2 a small prospective study of 81 pregnancies describes 43 pregnant women treated for 10 days with doxycycline during early first trimester. all mothers reported their exposed infants were normal at 1 year of age. 3

iduals with severe renal insufficiency (creatinine clearance below 10 ml/min). studies have shown no significant difference in serum half-life of doxycycline (range 18 to 22 hours) in individuals with normal and severely impaired renal function. hemodialysis does not alter serum half-life. population pharmacokinetic analysis of sparse concentration-time data of doxycycline following standard of care intravenous and oral dosing in 44 pediatric patients (2-18 years of age) showed that allometrically-scaled clearance (cl) of doxycycline in pediatric patients ≥2 to ≤8 years of age (median [range] 3.58 [2.27-10.82] l/h/70 kg, n=11) did not differ significantly from pediatric patients >8 to 18 years of age (3.27 [1.11-8.12] l/h/70 kg, n=33). for pediatric patients weighing ≤45 kg, body weight normalized doxycycline cl in those ≥2 to ≤8 years of age (median [range] 0.071 [0.041-0.202] l/kg/h, n=10) did not differ significantly from those >8 to 18 years of age (0.081 [0.035-0.126] l/kg/h, n=8). in pediatric patients weighing >45 kg, no clinically significant differences in body weight normalized doxycycline cl were observed between those ≥2 to ≤8 years (0.050 l/kg/h, n=1) and those >8 to 18 years of age (0.044 [0.014-0.121] l/kg/h, n=25). no clinically significant difference in cl between oral and iv dosing was observed in the small cohort of pediatric patients who received the oral (n=19) or iv (n=21) formulation alone. microbiology: mechanism of action doxycycline inhibits bacterial protein synthesis by binding to the 30s ribosomal subunit. doxycycline has bacteriostatic activity against a broad range of gram-positive and gram-negative bacteria. cross resistance with other tetracyclines is common. resistance cross resistance with other tetracyclines is common. antimicrobial activity doxycycline has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections (see indications and usage ) . gram-negative bacteria: acinetobacter species bartonella bacilliformis brucella species campylobacter fetus enterobacter aerogenes escherichia coli francisella tularensis haemophilus ducreyi haemophilus influenzae klebsiella granulomatis klebsiella species neisseria gonorrhoeae shigella species vibrio cholerae yersinia pestis gram-positive bacteria: bacillus anthracis listeria monocytogenes streptococcus pneumoniae anaerobes: clostridium species fusobacterium fusiforme propionibacterium acnes other bacteria: nocardiae and other actinomyces species borrelia recurrentis chlamydophila psittaci chlamydia trachomatis mycoplasma pneumoniae rickettsiae treponema pallidum treponema pallidum subspecies pertenue ureaplasma urealyticum parasites: balantidium coli entamoeba species susceptibility testing methods for specific information regarding susceptibility test interpretive criteria and associated test methods and quality control standards recognized by fda for this drug, please see: https://www.fda.gov/stic .

when the antibiotic is discontinued. sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibiotic. if this occurs, patients should contact their physician as soon as possible. patients should be counseled that antibacterial drugs including doxycycline tablets should only be used to treat bacterial infections. they do not treat viral infections (e.g., the common cold). when doxycycline tablets are prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by doxycycline tablets or other antibacterial drugs in the future.