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  • Tetracyclins are a structurally-related class of bacterial ribosome inhibitors. Their chemical structure is based around four fused carbon rings which gives this class its namesake.
Mechanism of Action
  • Inhibits the 30S subunit of the bacterial ribosome.
  • Tetracyclines chelate (i.e. bind) Ca++ and Mg++ ions and when they do so cannot be absorbed by the alimentary tract. This is more true of Tetracycline and Doxycycline; consequently, their ingestion on an empty stomach allows significantly better absorption.
Adverse Effects
  • GI System: Can cause diarrhea and gastric discomfort due to irritation of the GI mucosa
  • Skin: Can cause a dermatitis (i.e. sunburn) when patient is exposed to UV light or sunlight
  • Hepatotoxicity: Usually occurs only in pregnant women
  • Teeth and bone: Tetracyclins bind calcium and in doing so can cause discoloration of teeth and reduced bone growth, especially in children.
Member Drugs
  • Tetracycline
  • Doxycycline