Tetracycline (icon) is a broad-spectrum polyketide
Polyketides are secondary metabolites from bacteria, fungi, plants, and animals. Polyketides are usually biosynthesized through the decarboxylative condensation of malonyl-CoA derived extender units in a similar process to fatty acid synthesis...

An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...

 produced by the Streptomyces
Streptomyces is the largest genus of Actinobacteria and the type genus of the family Streptomycetaceae. Over 500 species of Streptomyces bacteria have been described. As with the other Actinobacteria, streptomycetes are gram-positive, and have genomes with high guanine and cytosine content...

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of Actinobacteria
Actinobacteria are a group of Gram-positive bacteria with high guanine and cytosine content. They can be terrestrial or aquatic. Actinobacteria is one of the dominant phyla of the bacteria....

, indicated for use against many bacterial infections. It is a protein synthesis inhibitor. It is commonly used to treat acne
Acne vulgaris
Acne vulgaris is a common human skin disease, characterized by areas of skin with seborrhea , comedones , papules , pustules , Nodules and possibly scarring...

 today, and, more recently, rosacea
Rosacea is a chronic condition characterized by facial erythema . Pimples are sometimes included as part of the definition. Unless it affects the eyes, it is typically a harmless cosmetic condition...

, and is historically important in reducing the number of deaths from cholera
Cholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae. The main symptoms are profuse watery diarrhea and vomiting. Transmission occurs primarily by drinking or eating water or food that has been contaminated by the diarrhea of an infected person or the feces...

. Tetracycline is marketed under the brand names Sumycin, Tetracyn, and Panmycin, among others. Actisite is a thread-like fiber formulation, used in dental applications. It is also used to produce several semisynthetic derivatives, which together are known as the tetracycline antibiotics
Tetracycline antibiotics
Tetracyclines are a group of broad-spectrum antibiotics whose general usefulness has been reduced with the onset of bacterial resistance. Despite this, they remain the treatment of choice for some specific indications....

. The term tetracycline is also used to denote the 4-ring system of this compound; tetracyclines are related substances that contain the same 4-ring system.

Mechanism of action

Tetracyclines bind to the 30S subunit of microbial ribosomes. They inhibit protein synthesis by blocking the attachment of charged aminoacyl-tRNA. Thus they prevent introduction of new amino acids to the nascent peptide chain. The action is usually inhibitory and reversible upon withdrawal of the drug. Resistance to the tetracyclines results from changes in permeability of the microbial cell envelope. In susceptible cells, the drug is concentrated from the environment and does not readily leave the cell. In resistant cells, the drug is not actively transported into the cell or leaves it so rapidly that inhibitory concentrations are not maintained. This is often plasmid-controlled. Mammalian cells are not vulnerable to the effect of tetracyclines as these contain no 30S ribosomal subunit and therefore do not accumulate the drug.


The tetracyclines are a large family of antibiotics that were discovered as natural products by Benjamin Minge Duggar
Benjamin Minge Duggar
Benjamin Minge Duggar was an American plant physiologist, born at Gallion, Hale County, Alabama. He studied at several Southern schools, including Alabama Polytechnic Institute , and at Harvard, Cornell , and in Germany, Italy, and France...

 and first described in 1948. Under Yellapragada Subbarao
Yellapragada Subbarao
Yellapragada Subbarao was an Indian biochemist who discovered the function of Adenosine Triphosphate as a energy source in the cell, and made important contributions to the treatment of cancer. Most of his career was spent in the United States...

, Benjamin Duggar made his discovery of the first tetracycline antibiotic, Aureomycin
Chlortetracycline is a tetracycline antibiotic, and was the first tetracycline to be identified. It was discovered in 1945 by Dr. Benjamin Duggar working at Lederle Laboratories under the supervision of Dr.Subba Rao...

, at Lederle Laboratories
American Cyanamid
American Cyanamid was a large, diversified, American chemical manufacturer, founded by Frank Washburn in 1907. It was the only United States firm manufacturing the polio vaccine of the Sabin type....

 in 1945.

In 1950, Harvard Professor Robert Woodward determined the chemical structure of the related substance, oxytetracycline
Oxytetracycline was the second of the broad-spectrum tetracycline group of antibiotics to be discovered.Oxytetracycline works by interfering with the ability of bacteria to produce proteins that are essential to them. Without these proteins the bacteria cannot grow, multiply and increase in numbers...

 (Terramycin); the patent protection for its fermentation and production was also first issued in 1950. A research team of seven scientists (K.J. Brunings, Francis A. Hochstein, C.R. Stephens, L.H. Conover, Abraham Bavley, Richard Pasternack, and Peter P. Regna) at Pfizer
Pfizer, Inc. is an American multinational pharmaceutical corporation. The company is based in New York City, New York with its research headquarters in Groton, Connecticut, United States...

, in collaboration with Woodward, participated in the two-year research leading to the discovery.

Pfizer was of the view that it deserved the right to a patent on tetracycline and filed its Conover application in October 1952. Cyanamid filed its Boothe Morton application for similar rights in March 1953 while Heyden Chemicals filed its Minieri application in September 1953, named after scientist P. Paul Minieri
P. Paul Minieri
P. Paul Minieri, a graduate from New York University, was one of their most successful scientists. Minieri’s contribution to organic chemistry was first established while attending graduate school and working under the guidance of Professor John J. Ritter, he authored a thesis that later became the...

, in order to obtain a patent on tetracycline and its fermentation process. This resulted in Tetracycline litigation
Tetracycline litigation
The discovery of tetracycline engendered an enormous amount of litigation. In late 1958, the U.S. government charged Pfizer and American Cyanamid with price fixing in connection with tetracycline. That and other related litigation lasted until 1982...

 in which the winner would have to prove beyond reasonable doubt of priority invention and tetracycline’s natural state.

Nubian mummies studied in the 1990s were found to contain significant levels of tetracycline; there is evidence that the beer brewed at the time could have been the source. Tetracycline sparked the development of many chemically altered antibiotics, and in doing so has proved to be one of the most important discoveries made in the field of antibiotics. It is used to treat many Gram-positive and Gram-negative bacteria and some protozoa. Like some other antibiotics, it is also used in the treatment of acne
Acne is a general term used for acneiform eruptions. It is usually used as a synonym for acne vulgaris, but may also refer to:*Acne aestivalis*Acne conglobata*Acne cosmetica*Acne fulminans*Acne keloidalis nuchae*Acne mechanica...


Cautions, contraindications, side effects

Are as those of the tetracycline antibiotics
Tetracycline antibiotics
Tetracyclines are a group of broad-spectrum antibiotics whose general usefulness has been reduced with the onset of bacterial resistance. Despite this, they remain the treatment of choice for some specific indications....

  • Can stain developing teeth (even when taken by the mother during pregnancy)
  • Can cause permanent teeth discoloration (yellow-gray-brown); infancy and childhood to eight years old
  • Inactivated by Ca2+ ion
    An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...

    , not to be taken with milk
    Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...

    , yogurt, and other dairy
    Dairy product
    Dairy products are generally defined as foods produced from cow's or domestic buffalo's milk. They are usually high-energy-yielding food products. A production plant for such processing is called a dairy or a dairy factory. Raw milk for processing comes mainly from cows, and, to a lesser extent,...

  • Inactivated by aluminium
    Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

    , iron
    Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

     and zinc
    Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

    , not to be taken at the same time as indigestion remedies
  • Inactivated by common antacids and over-the-counter heartburn medicines
  • Skin
    -Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

     photo-sensitivity; exposure to the sun
    The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

     or intense light
    Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

     is not recommended
  • Drug-induced lupus
    Lupus erythematosus
    Lupus erythematosus is a category for a collection of diseases with similar underlying problems with immunity . Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...

    , and hepatitis
    Hepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...

  • Can induce microvesicular fatty liver
    Fatty liver
    Fatty liver, also known as fatty liver disease , is a reversible condition where large vacuoles of triglyceride fat accumulate in liver cells via the process of steatosis...

  • Tinnitus
    Tinnitus |ringing]]") is the perception of sound within the human ear in the absence of corresponding external sound.Tinnitus is not a disease, but a symptom that can result from a wide range of underlying causes: abnormally loud sounds in the ear canal for even the briefest period , ear...

  • May interfere with methotrexate
    Methotrexate , abbreviated MTX and formerly known as amethopterin, is an antimetabolite and antifolate drug. It is used in treatment of cancer, autoimmune diseases, ectopic pregnancy, and for the induction of medical abortions. It acts by inhibiting the metabolism of folic acid. Methotrexate...

     by displacing it from the various protein binding sites
  • Can cause breathing complications as well as anaphylactic shock in some individuals
  • Should be avoided during pregnancy
    Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

     as it may affect bone growth of the fetus
    A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...

  • Caution should be exercised in long term use with breastfeeding. Short-term use safe; bio-availability in milk is low to nil.

In 2010, the FDA added tetracycline to its Adverse Event Reporting System (AERS). The AERS contains a list of medications under investigation by the FDA for potential safety issues. The list is published quarterly and available online. The AERS cites a potential link between the use of tetracycline products and Stevens–Johnson syndrome, toxic epidermal necrolysis
Toxic epidermal necrolysis
Toxic epidermal necrolysis is a rare, life-threatening dermatological condition that is usually induced by a reaction to medications...

 and erythema multiforme
Erythema multiforme
Erythema multiforme is a skin condition of unknown cause, possibly mediated by deposition of immune complex in the superficial microvasculature of the skin and oral mucous membrane that usually follows an infection or drug exposure...



It is first-line therapy for Rocky Mountain spotted fever
Rocky Mountain spotted fever
Rocky Mountain spotted fever is the most lethal and most frequently reported rickettsial illness in the United States. It has been diagnosed throughout the Americas. Some synonyms for Rocky Mountain spotted fever in other countries include “tick typhus,” “Tobia fever” , “São Paulo fever” or “febre...

 (Rickettsia), Q fever
Q fever
Q fever is a disease caused by infection with Coxiella burnetii, a bacterium that affects humans and other animals. This organism is uncommon but may be found in cattle, sheep, goats and other domestic mammals, including cats and dogs...

 (Coxiella), psittacosis
In medicine , psittacosis — also known as parrot disease, parrot fever, and ornithosis — is a zoonotic infectious disease caused by a bacterium called Chlamydophila psittaci and contracted from parrots, such as macaws, cockatiels and budgerigars, and pigeons, sparrows, ducks, hens, gulls and many...

 and lymphogranuloma venereum
Lymphogranuloma venereum
Lymphogranuloma venereum is a sexually transmitted disease caused by the invasive serovars L1, L2, L2a or L3 of Chlamydia trachomatis....

 (Chlamydia), and to eradicate nasal carriage of meningococci
Neisseria meningitidis
Neisseria meningitidis, often referred to as meningococcus, is a bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life threatening sepsis. N. meningitidis is a major cause of morbidity and mortality during childhood in industrialized countries...

. Tetracycline tablets were used in the plague outbreak in India in 1992.

Doxycycline INN is a member of the tetracycline antibiotics group, and is commonly used to treat a variety of infections. Doxycycline is a semisynthetic tetracycline invented and clinically developed in the early 1960s by Pfizer Inc. and marketed under the brand name Vibramycin. Vibramycin...

 is also one (of many) recommended drugs for chemoprophylatic treatment of malaria
Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...

 in travels to areas of the world where malaria is endemic.

Other uses

Since tetracycline is absorbed into bone, it is used as a marker of bone growth for biopsies in humans. Tetracycline labeling is used to determine the amount of bone growth within a certain period of time, usually a period of approximately 21 days. Tetracycline is incorporated into mineralizing bone and can be detected by its fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...

. In double tetracycline labeling, a second dose is given 11–14 days after the first dose, and the amount of bone formed during that interval can be calculated by measuring the distance between the two fluorescent labels.

Tetracycline is also used as a biomarker in wildlife
Wildlife includes all non-domesticated plants, animals and other organisms. Domesticating wild plant and animal species for human benefit has occurred many times all over the planet, and has a major impact on the environment, both positive and negative....

 to detect consumption of medicine- or vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...

-containing baits.

In genetic engineering, tetracycline is used in transcriptional activation.
Tetracycline is also one of the antibiotics used to treat ulcers caused by bacterial infections.
In cancer research at Harvard Medical School, tetracycline has been used to switch off leukemia in genetically altered mice, and to do so reliably, when added to their drinking water.

Cell culture

Tetracycline is used in cell biology as a selective agent in cell culture systems. It is toxic to prokaryotic and eukaryotic cells and selects for cells harboring the bacterial tetr gene, which encodes a 399-amino acid membrane-associated protein. This protein actively exports tetracycline from the cell, rendering cells harboring this gene more resistant to the drug.
The yellow crystalline powder can be dissolved in water (20 mg/ml) or ethanol (5 mg/ml) and is routinely used at 10 mg/l in cell culture. In cell culture at 37 °C (98.6 °F) it is stable for days, with a half-life of approximately 24 hours.
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