Doxycycline

To reduce the development of drug-resistant bacteria and maintain effectiveness of doxycycline for injection and other antibacterial drugs, doxycycline for injection should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

Doxycycline is indicated in infections caused by the following microorganisms:

• Rickettsiae (Rocky Mountain spotted fever, typhus fever, and the typhus group,
• Q fever, rickettsialpox and tick fevers).
• Mycoplasma pneumoniae
  (PPLO, Eaton Agent).
• Agents of psittacosis and ornithosis.
• Agents of lymphogranuloma venereum and granuloma inguinale.
• The spirochetal agent of relapsing fever (
  Borrelia recurrentis
  ).

The following gram-negative microorganisms:

• Haemophilus ducreyi (
  chancroid
  ),
• Yersinia pestis
• Francisella tularensis,
• Bartonella bacilliformis,
• Bacteroides
  species,
• Vibrio cholerae and
• Campylobacte fetus,
• Brucella species (
  in conjunction with
  streptomycin).

Because many strains of the following groups of microorganisms have been shown to be resistant to tetracyclines, culture and susceptibility testing are recommended.

Doxycycline is 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,
• Haemophilus influenzae
  (respiratory infections),
• Klebsiella
  species (respiratory and urinary infections).

Doxycycline is indicated for treatment of infections caused by the following gram-positive microorganisms when bacteriologic testing indicates appropriate susceptibility to the drug:

Up to 44 percent of strains of

For upper respiratory infections due to group A beta-hemolytic streptococci, penicillin is the usual drug of choice, including prophylaxis of rheumatic fever.

Anthrax due to

When penicillin is contraindicated, doxycycline is an alternative drug in the treatment of infections due to:

• Neisseria gonorrhoeae
  and
  N. meningitidis,
• Treponema pallidum
  and
  Treponema pallidum
  subspecie
  s pertenue (syphilis and yaws),
• Listeria monocytogenes,
• Clostridium
  species,
• Fusobacterium fusiforme
  (Vincent's infection),
• Actinomyces
  species
  .

In acute intestinal amebiasis, doxycycline may be a useful adjunct to amebicides.

Doxycycline is indicated in the treatment of trachoma, although the infectious agent is not always eliminated, as judged by immunofluorescence.

Note: Rapid administration is to be avoided. Parenteral therapy is indicated only when oral therapy is not indicated. Oral therapy should be instituted as soon as possible. If intravenous therapy is given over prolonged periods of time, thrombophlebitis may result.

The usual dosage and frequency of administration of doxycycline for injection (100 to 200 mg/day) differs from that of the other tetracyclines (1 to 2 g/day). Exceeding the recommended dosage may result in an increased incidence of side effects.

Studies to date have indicated that doxycycline at the usual recommended doses does not lead to excessive accumulation of doxycycline in patients with renal impairment.

The usual dosage of doxycycline for injection is 200 mg on the first day of treatment administered in one or two infusions. Subsequent daily dosage is 100 to 200 mg depending upon the severity of infection, with 200 mg administered in one or two infusions.

In the treatment of primary and secondary syphilis, the recommended dosage is 300 mg daily for at least 10 days.

In the treatment of inhalational anthrax (post-exposure) the recommended dose is 100 mg of doxycycline, twice a day. Parenteral therapy is only indicated when oral therapy is not indicated and should not be continued over a prolonged period of time. Oral therapy should be instituted as soon as possible. Therapy must continue for a total of 60 days.

For all pediatric patients weighing less than 45 kg with severe or life-threatening infections (e.g., anthrax, Rocky Mountain spotted fever), the recommended dosage is 2.2 mg/kg of body weight administered every 12 hours. Children weighing 45 kg or more should receive the adult dose (see WARNINGS and PRECAUTIONS).

For pediatric 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/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.

In the treatment of inhalational anthrax (post-exposure) the recommended dose is 2.2 mg/kg of body weight, twice a day in children weighing less than 45 kg. Parenteral therapy is only indicated when oral therapy is not indicated and should not be continued over a prolonged period of time. Oral therapy should be instituted as soon as possible. Therapy must continue for a total of 60 days.

The duration of infusion may vary with the dose (100 to 200 mg per day), but is usually one to four hours. A recommended minimum infusion time for 100 mg of a 0.5 mg/mL solution is one hour. Therapy should be continued for at least 24 to 48 hours after symptoms and fever have subsided. The therapeutic antibacterial serum activity will usually persist for 24 hours following recommended dosage.

Intravenous solutions should not be injected intramuscularly or subcutaneously. Caution should be taken to avoid the inadvertent introduction of the intravenous solution into the adjacent soft tissue.

Gastrointestinal: anorexia, nausea, vomiting, diarrhea, glossitis, dysphagia, enterocolitis, inflammatory lesions (with monilial overgrowth) in the anogenital region, and pancreatitis. Hepatotoxicity has been reported rarely. These reactions have been caused by both the oral and parenteral administration of tetracyclines. Superficial discoloration of the adult permanent dentition, reversible upon drug discontinuation and professional dental cleaning has been reported. Permanent tooth discoloration and enamel hypoplasia may occur with drugs of the tetracycline class when used during tooth development (see WARNINGS).

Skin: Maculopapular and erythematous rashes and fixed drug eruption have been reported. Exfoliative dermatitis 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).

Immune: Hypersensitivity reactions including urticaria, angioneurotic edema, anaphylaxis, anaphylactoid purpura, pericarditis, exacerbation of systemic lupus erythematosus, and drug reaction with eosinophilia and systemic symptoms (DRESS).

Other: Bulging fontanels in infants and intracranial hypertension in adults (see WARNINGS).

Blood: Hemolytic anemia, thrombocytopenia, neutropenia and eosinophilia have been reported.

Psychiatric: Depression, anxiety, suicidal ideation, insomnia, abnormal dreams, hallucination

When given over prolonged periods, tetracyclines have been reported to produce brown-black microscopic discoloration of thyroid glands. No abnormalities of thyroid function studies are known to occur.

Doxycycline for Injection, USP is a sterile, lyophilized powder prepared from a solution of doxycycline hyclate, ascorbic acid and mannitol in Water for Injection. Doxycycline hyclate is a broad spectrum antibiotic derived from oxytetracycline. It is meant for INTRAVENOUS use only after reconstitution. Doxycycline hyclate is a yellow to light yellow powder which is chemically designated 4-(Dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,5,10,12,12a-pentahydroxy-6-methyl-1,11- dioxo-2-naphthacenecarboxamide, monohydrochloride, compound with ethyl alcohol (2:1), monohydrate. It has the following structural formula:

Doxycycline hyclate is soluble in water and chars at 201°C without melting. The base doxycycline has a high degree of lipoid solubility and a low affinity for calcium binding. It is highly stable in normal human serum.

Each 100 mg vial contains: Doxycycline hyclate equivalent to 100 mg doxycycline; ascorbic acid 480 mg; mannitol 300 mg. pH of the reconstituted solution (10 mg/mL) is between 1.8 and 3.3.

Each 200 mg vial contains: Doxycycline hyclate equivalent to doxycycline 200 mg; ascorbic acid 960 mg; mannitol 600 mg. pH of the reconstituted solution (10 mg/mL) is between 1.8 and 3.3.

Tetracyclines are readily absorbed and are bound to plasma proteins in varying degree. They are concentrated by the liver in the bile, and excreted in the urine and feces at high concentrations and in a biologically active form.

Following a single 100 mg dose administered in a concentration of 0.4 mg/mL in a onehour infusion, normal adult volunteers average a peak of 2.5 mcg/mL, while 200 mg of a concentration of 0.4 mg/mL administered over two hours averaged a peak of 3.6 mcg/mL. Excretion of doxycycline by the kidney is about 40 %/72 hours in individuals with normal function (creatinine clearance about 75 mL/min). This percentage excretion may fall as low as 1 to 5 %/72 hours in individuals 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 this 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 to 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 to 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 to 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 to 0.202] L/kg/h, N=10) did not differ significantly from those >8 to 18 years of age (0.081 [0.035 to 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 to 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.

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.

Doxycycline has been shown to be active against most isolates of the following microorganisms, both

Rickettsiae

*Doxycycline has been found to be active against the asexual erythrocytic forms of

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.