though 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 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 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 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 tablets are an alternative drug in the treatment of the following infections: uncomplicated gonorrhea caused by neisseria gonorrhoeae . syphilis caused by treponema pallidum. yaws caused by treponema pallidum subspecies 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 tablets may be a useful adjunct to amebicides. in severe acne, doxycycline tablets may be useful adjunctive therapy.

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. 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 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.

c patients with less severe disease (greater than 8 years of age and weighing less than 45 kg), the recommended dosage schedule is 4.4 mg per kg of body weight divided into two doses on the first day of treatment, followed by a maintenance dose of 2.2 mg per 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 tablets, by mouth, twice a day for 60 days. children: weighing less than 100 pounds (45 kg); 1 mg/lb (2.2 mg/kg) of body weight, by mouth, twice a day for 60 days. children weighing 100 pounds or more should receive the adult dose.

has been 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.

renal insufficiency (creatinine clearance below 10 ml/min). studies have shown no significant difference in serum half-life of doxycycline (range 18to22 hours) in individuals with normal and severely impaired renal function. hemodialysis does not alter serum half-life. 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. 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 ). gramnegative 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 grampositive bacteria bacillus anthracis listeria monocytogenes streptococcus pneumoniae anaerobic bacteria 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 when available, the clinical microbiology laboratory should provide cumulative reports of in vitro susceptibility test results for antimicrobial drugs used in local hospitals and practice areas as periodic reports that describe the susceptibility profile of nosocomial and community-acquired pathogens. these reports should aid the physician in selecting the most effective antimicrobial. dilution techniques quantitative methods are used to determine antimicrobial minimum inhibitory concentrations (mics). these mics provide estimates of the susceptibility of bacteria to antimicrobial compounds. the mics should be determined using a standardized test method (broth and/or agar). 1,2,4,6,7 the mic values should be interpreted according to criteria provided in table 1. diffusion techniques quantitative methods that require measurement of zone diameters can also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. the zone size should be determined using a standardized test method . 1,3,4 this procedure uses paper disks impregnated with 30 mcg doxycycline to test the susceptibility of microorganisms to doxycycline. the disk diffusion interpretive criteria are provided in table 1. anaerobic techniques for anaerobic bacteria, the susceptibility to doxycycline can be determined by a standardized test method. 1,5 the mic values obtained should be interpreted according to the criteria provided in table 1 table 1: susceptibility test interpretive criteria for doxycycline and tetracycline bacteria* minimal inhibitory concentration (mcg per ml) zone diameter (mm) agar dilution (mcg per ml) s i r s i r s i r acinetobacter spp. doxycycline ≤ 4 8 ≥ 16 ≥ 13 10 to 12 ≤ 9 - - - tetracycline ≤ 4 8 ≥ 16 ≥ 15 12 to 14 ≤ 11 - - - anaerobes tetracycline - - - - - - ≤ 4 8 ≥ 16 bacillus anthracis † doxycycline ≤ 1 - - - - - - - - tetracycline ≤ 1 - - - - - - - - brucella species† doxycycline ≤ 1 - - - - - - - - tetracycline ≤ 1 - - - - - - - - enterobacteriaceae doxycycline ≤ 4 8 ≥ 16 ≥ 14 11 to 13 ≤ 10 - - - tetracycline ≤ 4 8 ≥ 16 ≥ 15 12 to 14 ≤ 11 - - - franciscella tularensis † doxycycline ≤ 4 - - - - - - - - tetracycline ≤ 4 - - - - - - - - haemophilus influenzae - - - tetracycline ≤ 2 4 ≥ 8 ≥ 29 26 to 28 ≤ 25 - - - mycoplasma pneumoniae † tetracycline - - - - - - ≤ 2 - - neisseria gonorrhoeae ‡ tetracycline - - - ≥ 38 31 to 37 ≤ 30 ≤ 0.25 0.5 to 1 ≥ 2 norcardiae and other aerobic actinomyces species† doxycycline ≤ 1 2 to 4 ≥ 8 - - - - - - streptococcus pneumoniae doxycycline tetracycline < 0.25 ≤ 1 0.5 2 ≥ 1 ≥ 4 ≥ 28 ≥ 28 25 to 27 25 to 27 < 24 ≤ 24 - - - vibrio cholerae doxycycline ≤ 4 8 ≥ 16 - - - - - - tetracycline ≤ 4 8 ≥ 16 - - - - - - yersinia pestis doxycycline ≤ 4 8 ≥ 16 - - - - - - tetracycline ≤ 4 8 ≥ 16 - - - - - - ureaplasma urealyticum tetracycline - - - - - - ≤ 1 - ≥ 2 * organisms susceptible to tetracycline are also considered susceptible to doxycycline. however, some organisms that are intermediate or resistant to tetracycline may be susceptible to doxycycline. † the current absence of resistance isolates precludes defining any results other than "susceptible". if isolates yielding mic results other than susceptible, they should be submitted to a reference laboratory for further testing. ‡ gonococci with 30 mcg tetracycline disk zone diameters of less than 19 mm usually indicate a plasmid-mediated tetracycline resistant neisseria gonorrhoeae isolate. resistance in these strains should be confirmed by a dilution test (mic ≥ 16 mcg per ml). a report of susceptible (s) indicates that the antimicrobial is likely to inhibit growth of the microorganism if the antimicrobial drug reaches the concentration usually achievable at the site of infection. a report of intermediate (i) indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. this category implies possible clinical applicability in body sites where the drug product is physiologically concentrated or in situations where high dosage of drug can be used. this category also provides a buffer zone that prevents small uncontrolled technical factors from causing major discrepancies in interpretation. a report of resistant (r) indicates that the antimicrobial drug is not likely to inhibit growth of the microorganism if the antimicrobial drug reaches the concentrations usually achievable at the infection site; other therapy should be selected. quality control standardized susceptibility test procedures require the use of laboratory controls to monitor and ensure the accuracy and precision of the supplies and reagents used in the assay, and the techniques of the individuals performing the test. 1,2,3,4,5,6,7 standard doxycycline and tetracycline powders should provide the following range of mic values noted in table 2. for the diffusion technique using the 30 mcg doxycycline disk or 30 mcg tetracycline disk, the criteria noted in table 2 should be achieved. table 2: acceptable quality control ranges for susceptibility testing for doxycycline and tetracycline qc strain minimal inhibitory concentration (mcg per ml) zone diameter (mm) agar dilution (mcg per ml) enterococcus faecalis atcc 29212 doxycycline 2 to 8 - - tetracycline 8 to 32 - - escherichia coli atcc 25922 doxycycline 0.5 to 2 18 to 24 - tetracycline 0.5 to 2 18 to 25 - eggerthella lenta atcc 43055 doxycycline 2 to 16 haemophilus influenzae atcc 49247 tetracycline 4 to 32 14 to 22 - neisseria gonorrhoeae atcc 49226 tetracycline - 30 to 42 0.25 to 1 staphylococcus aureus atcc 25923 doxycycline - 23 to 29 - tetracycline - 24 to 30 - staphylococcus aureus atcc 29213 doxycycline 0.12 to 0.5 - - tetracycline 0.12 to 1 - - streptococcus pneumoniae atcc 49619 doxycycline 0.015 to 0.12 25 to 34 - tetracycline 0.06 to 0.5 27 to 31 - bacteroides fragilis atcc 25285 tetracycline - - 0.125 to 0.5 bacteroides thetaiotaomicron atcc 29741 doxycycline tetracycline 2 to 8 - - 8 to 32 mycoplasma pneumoniae atcc 29342 tetracycline 0.06 to 0.5 - 0.06 to 0.5 ureaplasma urealyticum atcc 33175 tetracycline - - ≥ 8 * atcc is the american type culture collection

3304-132-10 bottles of 1000 doxycycline tablets 150 mg are white colored, convex faced, film-coated, debossed with “ rx ” above the bisect and “ 173 ” below the bisect on one side and plain on the other side. each tablet contains doxycycline monohydrate, usp equivalent to 150 mg of doxycycline. they are supplied as follows: ndc 63304-173-03 bottles of 10 ndc 63304-173-30 bottles of 30 ndc 63304-173-10 bottles of 1000 ndc 63304-173-69 blister pack of 10 store at 20° - 25° c (68° - 77° f) [see usp controlled room temperature]. protect from light. dispense in a tight light resistant container as defined in the usp/nf. storage of blister pack protect from light. retain in carton until time of use. you may report side effects to fda at 1-800-fda-1088.