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17 Cards in this Set
- Front
- Back
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Type |
Broad spectrum polyketide antibiotic |
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Bactericidal or static? |
Bacteriostatic |
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Produced from |
streptomyces genus of actinobacteria |
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Mode of action |
Inhibits bacterial protein synthesis. By blocking attachment of - type of tRNA to the ribosome. |
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Mechanism of resistance in bacteria |
From horizontal transfer of a gene. This encodes a efflux pump that actively eject tetracycline from the cell |
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History |
First tetracycline antibiotic : chlortetracycline discovered in 1945 by Benjamin Duggar |
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Precautions on teeth |
Can discolour permanent teeth ( yellow, grey, brown) If taken during their development. If mother takes the med, childs teeth can be affected. Tetracycline binds to the calcium ions in teeth. |
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Different teeth stains |
Before eruption, it will cause an initial fluorescent yellow discolouration. After eruption, the calcium bound tetracycline will oxidise , changes to non fluorescent brown. The stains are permanent. |
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Prevention of tetracycline teeth stains |
Avoid tetracycline in second and third pregnancy trimester until the age of 8 years in a child. These are the periods of teeth calcification
Can also happen in adults on long term tetracycline therapy |
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tetracycline and milk |
Inactivated by calcium ions. Hence not taken with milk, yoghurt and other diary products. |
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Precautions with antacids |
Inactivated by aluminium, iron and zinc. |
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Tetracycline and photosensitivity main sitesaffected |
Face, anterior portions of leg, dorsa of hands, nuchal region ( back of neck) |
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Symptoms of tetracycline photosensitivity |
Exaggerated sunburn, edema, erythema, blisters rarely with tenderness, burning pain. Hyperpigmentation may persist. |
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Photo-onycholysis in tetracycline |
Seperation of the nail from the nailbed after exposure to uv radiation |
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Pseudoporphyria |
Bullae, skin fragility, scarring, easy bruising. Seen in tetracycline and dapsone. Disappears after stopping drug |
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Other precautions |
Drug induced lupus and hepatitis Fatty liver Tinnitus Interfere with methotrexate Anaphylactic shock in some individuals Affect bone growth of the foetus so avoided in pregnancy Fanconi syndrome |
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Fanconi syndrome due to tetracycline |
Inadequate reabsorbtion in proximal renal tubules of kidney
Expired tetracycline changes to epitetracycline and anhydrotetracycline which damages the proximal tubule. |
