Tetracycline, Uses, Dosage, Side effects, Interactions, Pregnancy

Tetracycline, Uses, Dosage, Side effects, Interactions, Pregnancy

Tetracycline is a broad-spectrum naphthacene antibiotic produced semisynthetically from chlortetracycline, an antibiotic isolated from the bacterium Streptomyces aureofaciens. In bacteria, tetracycline binds to the 30S ribosomal subunit, interferes with the binding of aminoacyl-tRNA to the mRNA-ribosome complex, thereby inhibiting protein synthesis.

Tetracycline is a broad spectrum polyketide antibiotic produced by the Streptomyces genus of Actinobacteria. It exerts a bacteriostatic effect on bacteria by binding reversible to the bacterial 30S ribosomal subunit and blocking incoming aminoacyl tRNA from binding to the ribosome acceptor site.

Machanism of Action of Tetracycline

Tetracycline passively diffuses through porin channels in the bacterial membrane and reversibly binds to the 30S ribosomal subunit, preventing binding of tRNA to the mRNA-ribosome complex, and thus interfering with protein synthesis.

Tetracycline is a short-acting antibiotic that inhibits bacterial growth by inhibiting translation. It binds to the 30S ribosomal subunit and prevents the amino-acyl tRNA from binding to the A site of the ribosome. It also binds to some extent to the 50S ribosomal subunit. This binding is reversible in nature. Additionally tetracycline may alter the cytoplasmic membrane of bacteria causing leakage of intracellular contents, such as nucleotides, from the cell.

The hepatotoxic effects of tetracycline (I), rolitetracycline, and doxycycline were studied in male and female mice. All antibiotics (25-100 ug/g) increased the amount of unconjugated and total bilirubin. This effect was most pronounced after tetracycline, which also reduced the level of conjugated bilirubin. All drugs increased serum transaminase enzyme levels; this effect was more pronounced in females.

Indications of Tetracycline

  • Bacterial Infection
  • Bladder Infection
  • Acne
  • Bronchitis
  • Brucellosis
  • Bullous Pemphigoid
  • Chlamydia Infection
  • Ehrlichiosis
  • Epididymitis, Sexually Transmitted
  • Gonococcal Infection, Uncomplicated
  • Helicobacter Pylori Infection
  • Lyme Disease, Arthritis
  • Lyme Disease, Erythema Chronicum Migrans
  • Lyme Disease, Neurologic
  • Lymphogranuloma Venereum
  • Nongonococcal Urethritis
  • Ocular Rosacea
  • Ornithosis
  • Pelvic Inflammatory Disease
  • Pemphigoid
  • Pemphigus
  • Pneumonia
  • Psittacosis
  • Rheumatoid Arthritis
  • Rickettsial Infection
  • Syphilis, Early
  • Syphilis, Latent
  • Tertiary Syphilis
  • Upper Respiratory Tract Infection

Used to treat bacterial infections such as Rocky Mountain spotted fever, typhus fever, tick fevers, Q fever, rickettsialpox and Brill-Zinsser disease. May be used to treat infections caused by Chlamydiae spp., B. burgdorferi (Lyme disease), and upper respiratory infections caused by typical (S. pneumoniae, H. influenzae, and M. catarrhalis) and atypical organisms (C. pneumoniae, M. pneumoniae, L. pneumophila). May also be used to treat acne. Tetracycline may be an alternative drug for people who are allergic to penicillin.

Therapeutic Indications of Tetracycline

  • Tetracycline hydrochloride ointment is used in the prophylaxis of minor bacterial skin infections and in the treatment of dermal ulcer.
  • Tetracycline hydrochloride ointment is indicated in the topical treatment of minor skin infections caused by streptococci, staphylococci, and other susceptible organisms.
  • Tetracycline hydrochloride for topical solution is indicated for the topical treatment of acne vulgaris. It may be effective in grades II and III acne, which are characterized by inflammatory lesions such as papules and pustules.
  • Ophthalmic tetracycline is used in the treatment of chlamydia infections and ocular rosacea.
  • Ophthalmic tetracycline is used in the treatment of bacterial blepharitis, blepharoconjunctivitis, bacterial conjunctivitis, bacterial keratitis, bacterial keratoconjunctivitis, and meibomianitis.
  • Ophthalmic tetracycline is indicated in the treatment of trachoma caused by Chlamydia trachomatis. It should be used concurrently with oral tetracyclines.
  • Ophthalmic tetracycline is indicated in the prophylaxis of ophthalmia neonatorum caused by Neisseria gonorrhoea and Chlamydia trachomatis.
  • phthalmic tetracycline is indicated in the treatment of superficial ocular infections caused by Staphylococcus aureus, streptococci including Streptococcus epidermicus (Streptococcus pyogenes) and Staphylococcus pneumonia (Diplococcus pneumonia), Neisseria gonorrhoea, and Escherichia coli.
  • The intrapleural administration of tetracycline solution as a sclerosing agent for the treatment of recurrent malignant pleural effusions is discussed. The usual dose is 500 mg tetracycline hydrochloride diluted in 30-50 ml saline, instilled via a chest tube into the pleural space. Side effects have not been a problem. Considering the effective control rate, toxicity, availability and ease of administration, intrapleural tetracycline appears safe and effective and is considered the first choice for local therapy.
  • Standardized enamel and dentin specimens were impregnated in aqueous solutions of tetracycline HCl, oxytetracycline HCl or doxycyline HCl, rinsed in water, and stored dry for 200 days. Another series of specimens were impregnated in solutions of doxycyline HCl and then rinsed in tap water for varying periods up to 35 days.
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Contra Indications of Tetracycline

  • History of severe hypersensitivity (e.g. anaphylactic reaction) to any other type of betalactam antibacterial agent (penicillins, monobactams and carbapenems).
  • Hemolytic anemia
  • Liver problems
  • Interstitial nephritis
  • Subacute cutaneous lupus erythematosus
  • Systemic lupus erythematosus
  • Tetracycline use should be avoided in pregnant or lactating women, and in children with developing teeth because they may result in permanent staining (dark yellow-gray teeth with a darker horizontal band that goes across the top and bottom rows of teeth), and possibly affect the growth of teeth and bones.
  • Usage during the first 12 weeks of pregnancy does not appear to increase the risk of any major birth defects. There may be a small increased risk for minor birth defects such as an inguinal hernia, but the number of reports is too small to be sure if there actually is any risk.

Dosage of Tetracycline 


  • 500 mg orally twice a day for 2 weeks or more, depending on the nature and severity of the infection


  • 500 mg orally every 6 hours for 7 to 10 days, depending on the nature and severity of the infection; may be given for 4 to 5 days a week during winter months as prophylaxis against chronic infectious bronchitis


  • 500 mg orally 4 times a day for 3 weeks given with streptomycin 1 g IM twice a day the first week and once a day the second week

Chlamydia Infection

  • Uncomplicated urethral, endocervical, or rectal infection: 500 mg orally 4 times a day for at least 7 days
  • The patient’s sexual partner(s) should also be evaluated/treated.
  • Oral doxycycline therapy is preferred by the Centers for Disease Control and Prevention (CDC) for the treatment of chlamydial infections in nonpregnant patients.
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Helicobacter pylori Infection

  • 500 mg orally every 6 hours for 14 days given in conjunction with bismuth, metronidazole, and an H2 blocker

Lyme Disease Arthritis

  • 500 mg orally every 6 hours for 14 to 30 days, depending on the nature and severity of the infection

Lyme Disease Carditis

  • 500 mg orally every 6 hours for 14 to 30 days, depending on the nature and severity of the infection

Lyme Disease  Erythema Chronicum Migrans

  • 500 mg orally every 6 hours for 10 to 30 days, depending on the nature and severity of the infection


  • 500 mg orally every 6 hours for 10 to 21 days, depending on the nature and severity of the infection

Upper Respiratory Tract Infection

  • 500 mg orally every 6 hours for 7 to 10 days, depending on the nature and severity of the infection


  • 500 mg orally 4 times a day; initial treatment with IV doxycycline may be necessary for seriously ill patients
  • Duration: Treatment should continue at least 10 to 14 days after fever subsides to prevent relapse

Nongonococcal Urethritis

  • 500 mg orally every 6 hours for 7 days

Gonococcal Infection

  • 500 mg orally 4 times a day for 7 days


  • 500 mg orally every 6 hours for 3 to 7 days, depending on the nature and severity of the infection; recommended if no alternatives exist

Side Effects of Tetracycline 

The most common side effects 

More common


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Drug Interactions of Tetracycline

Tetracycline may interact with following drugs, suppliments, & may change the efficacy of drugs

Pregnancy & Lactation of Tetracycline 

FDA Pregnancy Category D 


Tetracycline is classified pregnancy category D. All tetracyclines have a detrimental effect on the skeletal development and bone growth of the fetus or child. They should not be used in the second half of pregnancy unless benefits from treatment outweigh the risks to the fetus, and their use should be considered only with extreme caution.


Tetracyclines also have a serious effect on the dentin and enamel of developing teeth, causing permanent yellow or brown discoloration and enamel hypoplasia. Except when other therapy is ineffective, use in neonates, infants, and children to the age of 8 years, should be avoided.Tetracyclines are distributed in small amounts into breast milk. In general, manufacturers recommend that tetracycline antibiotics not be used in breast feeding mothers due to a theoretical risk of causing teeth discoloration, enamel hypoplasia,



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