CHEMICALS SUMMARY PAGE

Tetracycline

Summary Information
Classification Chemicals / Complex Chemical Agents / Type:

(This chemicals section is currently predominantly used in Wildpro to link different data types and demonstrate inter-relationships. It does not contain detailed information on the chemical itself.)

Alternative Names --
Notes Information in this page has been entered to support the current volumes of Wildpro and further information will be added as new volumes are completed. This page is not intended to substitute for the manufacturer's data sheet and the information is not yet complete for all species, or for all contra-indications etc.

CAUTION: Before any pharmaceutical product is used, the manufacturer's data sheet, containing information on uses, dosage and administration, contra-indications, warnings etc., should always be consulted. It is important to remember that licensing of pharmaceutical products for use in a particular species/condition, as well as mandatory meat and milk withdrawal times for food-producing animals, varies between countries and changes with time. Withdrawal times also may vary between different pharmaceutical formulations and depending on route of administration. In the EU, the prescription cascade must be followed (see LCofC1.2H and W564.Apr05.w1); note that specific restrictions apply for food-producing animals. In the USA, FARAD may be consulted regarding residues and meat and milk withdrawal times.

  • Tetracyclines enter microorganisms partially by passive diffusion, partly by energy-dependant active transport. Susceptible cells concentrate the drug. (B135.44.w44)
  • With the cell, tetracyclines bind reversibly to receptors on the 30S ribosomal subunit, blocking the binding of aminoacyl-tRNA to the acceptor site on the mRNA-ribosome complex and thus effectively preventing addition of new amino acids to the peptide chain, therefore inhibiting protein synthesis. (B135.44.w44, B263)
  • Tetracyclines are also believed to bid reversibly to 50S subunit of ribosomes and additionally alter cytoplasmic membrane permeability in susceptible organisms. (B263)
  • In high concentration, tetracyclines can inhibit protein synthesis in mammalian cells. (B263)

Pharmacokinetics

  • Absorbed mainly from the upper small intestine. (B135.44.w44)
  • Better absorption in the absence of food. (B135.44.w44, B263)
  • Absorption is impaired by chelation with divalent cations Ca2+, Mg2+, Fe2+ and with AL3+, particularly in milk or antacids. (B135.44.w44); reduction may be 50%. (B263)
  • Absorption is impaired by alkaline pH. (B135.44.w44)
  • Tetracyclines are 40-80% protein-bound. (B135.44.w44)
  • Wide distribution in tissues and body fluids. (B135.44.w44): distributed to heart, kidney, lungs, muscle, pleural fluid, bronchial secretions, sputum, bile, saliva, urine, synovial fluid, ascitic fluid, ocular aqueous humour and vitreous humour. (B263)
  • Only low concentrations in CSF. (B135.44.w44, B263)
  • 10-50% of tetracyclines are excreted, primarily by glomerular filtration, in urine. (B135.44.w44)

Drug interactions:

  • Orally administered tetracyclines may chelate divalent or trivalent cations: absorption of the tetracycline/other preparation may be decreased: oral administration should be separated by at least one to two hours. (B263). 
  • Decreased adsorption of orally administered tetracyclines in the presence of oral iron products: give iron salts at least three hours before or two hours after the tetracycline. (B263)
  • Decreased absorption of orally administered tetracyclines may occur if given together with oral sodium bicarbonate, kaolin, pectin or bismuth subsalicylate. (B263)
  • Tetracyclines, being bacteriostatic, may interfere with the bactericidal effect of beta-lactam antibiotics (penicillins and cephalosporins) and aminoglycosides (some controversy regarding the clinical significance). (B263)
  • Tetracyclines may, in a small proportion of human patients, increase digoxin bioavailability, leading to digoxin toxicity: this effect may persist for months after the tetracycline administration is discontinued. (B263).
  • Tetracyclines may depress the activity of plasma prothrombin: individuals receiving anticoagulants such as warfarin may require adjustment of their anticoagulant dose. (B263)
  • Reportedly (not yet confirmed by controlled studies), tetracyclines may reduce the insulin requirements of diabetic individuals. (B263)
  • May increase the nephrotoxic effects of methoxyflurane. (B263)
  • Concurrent use with theophylline may lead to increased gastro-intestinal side effects. (B263)
Administration

Lagomorphs - Oryctolagus cuniculus domesticus - Domestic rabbit:

  • 50 mg/kg orally every 8 - 12 hours. (B548.w8)
  • 50 - 100 mg/kg orally every eight hours. (B548.w8)

Ferrets - Mustela putorius fero - Ferret:

  • 20 mg/kg orally three times daily. Potential for renal disease in geriatric ferrets, and may cause discolouration of the teeth in neonatal animals. (B626.App.w22)
  • 20 - 25 m/kg orally every 8 - 12 hours. (B602.41.w41)
  • 25 mg/kg twice or three times daily. (J213.3.w1)

Great Apes

  • 25 - 50 mg/kg orally every 24 hours for 5 - 10 days. For the treatment of Entamoeba and Balantidium infections. (B336.39.w39)
  • Adult Pan troglodytes - Chimpanzee: 20 - 25 mg/kg orally twice daily or three times daily. (W768.Jun2012.w1)
  • Primates: 25 mg/kg orally, intramuscularly or intravenously, twice daily. (D425.3.15.w3o)
  • Primates: 15 mg/kg orally four times daily for 14 days. In the treatment of Balantidium coli Infection. (D425.3.15.w3o)

Return to Top of Page