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Demeclocycline (Monograph)

Brand name: Declomycin
Drug class: Tetracyclines
VA class: AM250
CAS number: 64-73-3

Medically reviewed by on Jun 21, 2022. Written by ASHP.


Antibacterial; tetracycline antibiotic derived from Streptomyces aureofaciens.

Uses for Demeclocycline

Respiratory Tract Infections

Treatment of respiratory tract infections caused by Mycoplasma pneumoniae.

Treatment of respiratory tract infections caused by Haemophilus influenzae, Streptococcus pneumoniae, or Klebsiella. Should only be used for treatment of infections caused by these bacteria when in vitro susceptibility tests indicate the organism is susceptible.

Acinetobacter Infections

Treatment of infections caused by Acinetobacter; minocycline may be the preferred tetracycline for use as an alternative to imipenem or meropenem.


Adjunctive treatment of moderate to severe inflammatory acne. Not indicated for treatment of noninflammatory acne.


Treatment of actinomycosis caused by Actinomyces israelii; oral tetracyclines used as follow-up after initial parenteral treatment with penicillin G.


Adjunct to amebicides for treatment of acute intestinal amebiasis. Tetracyclines generally not recommended for treatment of amebiasis caused by Entamoeba.


Alternative to doxycycline for treatment of inhalational anthrax when a parenteral regimen is not available (e.g., when there are supply or logistic problems because large numbers of individuals require treatment in a mass casualty setting). A multiple-drug parenteral regimen (ciprofloxacin or doxycycline and 1 or 2 other anti-infectives predicted to be effective) is preferred for treatment of inhalational anthrax that occurs as the result of exposure to anthrax spores in the context of biologic warfare or bioterrorism.

Bartonella Infections

Treatment of infections caused by Bartonella bacilliformis.


Treatment of brucellosis; tetracyclines considered drugs of choice. Used in conjunction with other anti-infectives (e.g., streptomycin or gentamicin and/or rifampin), especially for severe infections or when there are complications (e.g., endocarditis, meningitis, osteomyelitis).

Campylobacter Infections

Treatment of infections caused by Campylobacter. Tetracyclines are alternatives, not drugs of choice.


Treatment of chancroid caused by Haemophilus ducreyi. Not included in CDC recommendations for treatment of chancroid.

Chlamydial Infections

Treatment of uncomplicated urethral, endocervical, or rectal infections caused by Chlamydia trachomatis. Doxycycline is the preferred tetracycline for treatment of these infections, including presumptive treatment of chlamydial infections in patients with gonorrhea.

Treatment of trachoma and inclusion conjunctivitis caused by C. trachomatis. Consider that anti-infectives may not eliminate C. trachomatis in all cases of chronic trachoma.

Treatment of lymphogranuloma venereum (genital, inguinal, or anorectal infections) caused by C. trachomatis. Doxycycline is the preferred tetracycline for these infections.

Treatment of psittacosis (ornithosis) caused by C. psittaci. Doxycycline and tetracycline are drugs of choice. For initial treatment of severely ill patients, use IV doxycycline.

Clostridium Infections

Alternative for treatment of infections caused by Clostridium. Tetracyclines are alternatives to metronidazole or penicillin G for adjunctive treatment of C. tetani infections.

Enterobacteriaceae Infections

Treatment of infections caused by susceptible Escherichia coli, Enterobacter aerogenes, Klebsiella, or Shigella. Should only be used for treatment of infections caused by these common gram-negative bacteria when other appropriate anti-infectives are contraindicated or ineffective and when in vitro susceptibility tests indicate the organism is susceptible.

Fusobacterium Infections

Alternative to penicillin G for the treatment of infections caused by Fusobacterium fusiforme (Vincent’s infection).

Gonorrhea and Associated Infections

Alternative for treatment of uncomplicated gonorrhea (including urethritis) caused by susceptible Neisseria gonorrhoeae. However, tetracyclines are considered inadequate therapy and are not recommended by CDC for treatment of gonorrhea.

Granuloma Inguinale (Donovanosis)

Treatment of granuloma inguinale (donovanosis) caused by Calymmatobacterium granulomatis. Doxycycline is the tetracycline recommended as drug of choice by CDC.

Listeria Infections

Alternative for treatment of listeriosis caused by Listeria monocytogenes. Not usually considered a drug of choice or alternative for these infections.

Nongonococcal Urethritis

Treatment of nongonococcal urethritis (NGU) caused by Ureaplasma urealyticum, C. trachomatis, or Mycoplasma. Doxycycline usually is the tetracycline of choice for NGU.

Consider that some cases of recurrent urethritis following treatment may be caused by tetracycline-resistant U. urealyticum.


Treatment of plague caused by Yersinia pestis. Regimen of choice is streptomycin or gentamicin (with or without doxycycline).

Relapsing Fever

Treatment of relapsing fever caused by Borrelia recurrentis. Tetracyclines are drugs of choice.

Rickettsial Infections

Treatment of rickettsial infections including Rocky Mountain spotted fever, typhus fever and the typhus group, Q fever, rickettsialpox, and tick fevers caused by Rickettsiae. Tetracyclines are drugs of choice for treatment of most rickettsial infections; doxycycline usually is the preferred tetracycline.

Syndrome of Inappropriate Antidiuretic Hormone Secretion

Treatment of syndrome of inappropriate antidiuretic hormone secretion [off-label] (SIADH). Only limited value in patients with acute water intoxication caused by excess ADH secretion, but may be effective in inhibiting the action of ADH in patients with chronic form of the disease.

Also has been used to treat hyponatremia and water retention [off-label] in patients with congestive heart failure or cirrhosis, but a high incidence of renal failure has been reported and the drug probably should not be used in these patients.


Alternative to penicillin G for treatment of primary, secondary, latent, or tertiary syphilis (not neurosyphilis) in nonpregnant adults and adolescents hypersensitive to penicillins. Doxycycline and tetracycline are the preferred tetracyclines in patients hypersensitive to penicillins. Use tetracyclines only if compliance and follow-up can be ensured since efficacy not well documented.


Treatment of tularemia caused by Francisella tularensis. Tetracyclines considered alternatives to streptomycin (or gentamicin); risk of relapse and primary treatment failure may be higher than with aminoglycosides.

Vibrio Infections

Treatment of cholera caused by Vibrio cholerae. Doxycycline and tetracycline are drugs of choice; used as an adjunct to fluid and electrolyte replacement in moderate to severe disease.


Alternative to penicillin G for treatment of yaws caused by Treponema pertenue.

Demeclocycline Dosage and Administration


Oral Administration

Administer orally 1 hour before or 2 hours after meals and/or milk.

Administer with adequate amounts of fluid to reduce the risk of esophageal irritation and ulceration.


Pediatric Patients

General Pediatric Dosage

Children >8 years of age: 7–13 mg/kg daily given in 2–4 divided doses.


General Adult Dosage

150 mg 4 times daily or 300 mg 2 times daily.

Gonorrhea and Associated Infections

600 mg initially followed by 300 mg every 12 hours for 4 days for a total of 3 g.

No longer recommended for gonorrhea by CDC or other experts.

Syndrome of Inappropriate Antidiuretic Hormone Secretion† [off-label]

600 mg to 1.2 g daily in 3 or 4 divided doses. Diuresis usually occurs within 5 days after initiation of therapy and reverses within 2–6 days after drug discontinued.

Prescribing Limits

Pediatric Patients

Maximum 600 mg daily.

Special Populations

Hepatic Impairment

Adjust dosage by decreasing doses or increasing dosing interval.

Use with caution.

Renal Impairment

Adjust dosage by decreasing doses or increasing dosing interval.

Use with caution.

Cautions for Demeclocycline


  • Known hypersensitivity to demeclocycline, other tetracyclines, or any ingredient in the formulation.



Adverse Dental and Bone Effects

Use during tooth development (e.g., pregnancy, children <8 years of age) may cause permanent yellow-gray to brown discoloration of teeth and enamel hypoplasia Effects are most common following long-term use, but may occur following repeated short-term use.

Tetracyclines form a stable calcium complex in any bone-forming tissue. Reversible decrease in fibula growth rate has occurred in prematures receiving tetracycline.

Use not recommended in children <8 years of age unless other appropriate drugs are ineffective or are contraindicated or unless the benefits in certain indications (e.g., anthrax) outweigh the risks. (See Pediatric Use under Cautions.)

Fetal/Neonatal Morbidity

Animal studies indicate possible fetal toxicity (e.g., retardation of skeletal development) and embryotoxicity. If used during pregnancy or if patient becomes pregnant while receiving demeclocycline, patient should be apprised of the potential hazard to the fetus. (See Pregnancy under Cautions.)

Nervous System Effects

Possibility of adverse CNS effects (light-headedness, dizziness, vertigo) that may impair ability to drive vehicles or operate hazardous machinery.

Benign intracranial hypertension (pseudotumor cerebri) in adults reported with tetracyclines; usually manifested as headache and blurred vision. Bulging fontanels reported in infants. Effects usually resolve when drug discontinued, but possibility for permanent sequelae exists.

Renal Effects

Tetracyclines have antianabolic effects and may increase BUN.

In patients with impaired renal function, high serum demeclocycline concentrations may result in azotemia, hyperphosphatemia, and acidosis. Excessive drug accumulation and possible liver toxicity may occur if usual dosage is used patients with renal impairment. (See Renal Impairment under Dosage and Administration.)

Diabetes Insipidus Syndrome

Diabetes insipidus syndrome (polyuria, polydipsia and weakness) reported with long-term demeclocycline therapy. Syndrome is nephrogenic, dose-dependent, and reversible when drug discontinued.

Laboratory Monitoring

Periodically assess organ system function, including renal, hepatic and hematopoietic, during long-term therapy.

Sensitivity Reactions

Photosensitivity Reactions

Photosensitivity, manifested by an exaggerated sunburn reaction, reported with tetracyclines.

Photosensitivity reactions may develop within a few minutes to several hours after sun exposure and usually persist 1–2 days after discontinuance of the drug. Most reactions result from accumulation of tetracyclines in skin and are phototoxic in nature; photoallergic reactions may also occur.

Discontinue drug at first evidence of skin erythema.

General Precautions


Possible emergence and overgrowth of nonsusceptible bacteria or fungi. Discontinue drug and institute appropriate therapy if superinfection occurs.

Selection and Use of Anti-infectives

Because many strains of Acinetobacter, Bacteroides, Enterobacter, E. coli, Klebsiella, Shigella, S. pyogenes (group A β-hemolytic streptococci), S. pneumoniae, enterococci, and α-hemolytic streptococci are resistant to tetracyclines (including demeclocycline), in vitro susceptibility tests should be performed if the drug is used for treatment of infections caused by these bacteria.

Incision and drainage or other surgical procedures should be performed in conjunction with demeclocycline therapy when indicated.

Specific Populations


Category D. (See Fetal/Neonatal Morbidity under Cautions.)


Distributed into milk; discontinue nursing or the drug.

AAP states maternal use of tetracyclines usually is compatible with breast-feeding since absorption of the drugs by nursing infants is negligible.

Pediatric Use

Should not be used in children <8 years of age unless benefits outweigh the risks. (See Adverse Dental and Bone Effects under Cautions.)

Hepatic Impairment

Use with caution. Reduce dosage.

Renal Impairment

Use with caution. Reduce dosage.

Because usual dosage of doxycycline can be used in patients with impaired renal function, it may preferred when a tetracycline is indicated in a patient with impaired renal function.

Common Adverse Effects

GI effects (anorexia, nausea, vomiting, diarrhea); maculopapular and erythematous rash; dose-related BUN increase; hypersensitivity reactions.

Interactions for Demeclocycline

Specific Drugs




Antacids (aluminum-, calcium-, or magnesium-containing)

Decreased demeclocycline absorption

Administer antacids containing aluminum, calcium, or magnesium 1–2 hours before or after demeclocycline

Anticoagulants, oral

Possible increased anticoagulant effect; tetracyclines may impair utilization of prothrombin or decrease vitamin K production by intestinal bacteria

Monitor PT carefully; adjust anticoagulant dosage as needed

Hormonal contraceptives

Possible decreased effectiveness of oral contraceptives

Use alternative nonhormonal contraceptives

Iron-containing preparations

Possible decreased absorption of demeclocycline

Administer demeclocycline 2 hours before or 3 hours after an oral iron preparation


Possible fatal nephrotoxicity

Concomitant use not recommended


Possible antagonism

Concomitant use not recommended

Demeclocycline Pharmacokinetics



Approximately 60–80% of a dose absorbed from the GI tract in fasting adults. Peak serum concentrations attained within 2–4 hours.


Food and/or milk decrease GI absorption by ≥50%.



Well distributed into body tissues and fluids.

Plasma Protein Binding




Does not appear to be metabolized.

Elimination Route

Excreted into the GI tract via bile and by nonbiliary routes. Excreted in urine by glomerular filtration.

44% of a 150-mg oral dose excreted in urine and 13–46% excreted in feces as unchanged drug.


Adults with normal renal function: 10–17 hours.

Special Populations

Patients with severe renal impairment: half-life 42–68 hours.






Actions and Spectrum

  • Usually bacteriostatic, but may be bactericidal in high concentrations or against highly susceptible organisms.

  • Inhibits protein synthesis in susceptible organisms by reversibly binding to 30S and 50S ribosomal subunits.

  • The complete mechanisms by which tetracyclines reduce acne lesions have not been fully elucidated. The effects appear to result in part from the antibacterial activity of the drugs, but other mechanisms also are involved.

  • Spectrum of activity includes many gram-positive and -negative bacteria and various other organisms (e.g., Rickettsia, Chlamydia, Mycoplasma, spirochetes). Inactive against fungi and viruses.

  • Gram-positive aerobes and anaerobes: active against Actinomyces israelii, Bacillus anthracis, Clostridium, Propionibacterium acnes, and some staphylococci and streptococci. Many strains of S. pyogenes and Enterococci are resistant.

  • Gram-negative aerobes and anaerobes: active against Bartonella bacilliformis, Brucella, Calymmatobacterium granulomatis, Francisella tularensis, Haemophilus ducreyi, H. influenzae, Neisseria gonorrhoeae, Vibrio cholerae, and Y. pestis. Many strains of Acinetobacter, E. aerogenes, E. coli, Klebsiella, and Shigella and nearly all strains of Proteus and Pseudomonas are resistant.

  • Other organisms: active against Rickettsia, Coxiella burnetii, Chlamydia psittaci, C. trachomatis, Mycoplasma hominis, M. pneumoniae, Ureoplasma urealyticum, B. recurrentis, Leptospira, Treponema pallidum, and T. pertenue.

  • Complete cross-resistance usually occurs between demeclocycline and other tetracyclines (doxycycline, minocycline, oxytetracycline, tetracycline).

Advice to Patients

  • Importance of drinking sufficient quantities of fluids when taking tablets to reduce the risk of esophageal irritation and ulceration.

  • Advise patients that absorption of demeclocycline may be reduced when taken with foods, especially those containing calcium, and that tablets should be taken at least 1 hour before or 2 hours after meals and/or milk.

  • Advise patients that adverse CNS effects (light-headedness, dizziness, vertigo) may occur and caution should be used when driving vehicles or operating hazardous machinery.

  • Advise patients to avoid excessive sunlight or artificial UV light and to discontinue the drug at the first sign of skin erythema; consider use of sunscreen or sunblock.

  • Advise patients that demeclocycline may decrease effectiveness of oral contraceptives and that alternative nonhormonal contraceptive measures should be used.

  • Advise patients that unused supplies of demeclocycline should be discarded by the expiration date.

  • Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed. (See Fetal/Neonatal Morbidity under Cautions.)

  • Importance of informing clinicians of existing or contemplated therapy, including prescription and OTC drugs.

  • Importance of informing patients of other important precautionary information. (See Cautions.)


Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Demeclocycline Hydrochloride


Dosage Forms


Brand Names





Tablets, film-coated

150 mg*



Demeclocycline Tablets

Barr, Impax

300 mg*



Demeclocycline Tablets

Barr, Impax

AHFS DI Essentials™. © Copyright 2023, Selected Revisions July 1, 2006. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

† Off-label: Use is not currently included in the labeling approved by the US Food and Drug Administration.

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