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41 Cards in this Set
- Front
- Back
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Contains beta-lactam ring and inhibit transpepidases which are responsible in establishing crosslinks in the peptidoglycan of bacteria. Bactericidal. Only effective against multiply organisms. |
Penicillins |
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Absorption - varies when given orally, delayed preparations available. |
Penicillins |
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Distribution - widely distributed throughout the body, do not normally enter CSF. |
Penicillins |
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Metabolism - Short half life (30-80 minutes) |
Penicillins |
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Excretion - mainily through kidney, 90% excreted by tubular secretion. |
Penicillins |
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Original form of penicillin, not very active against Gram negatives. Given by oral route, not very well absorbed. Acid labile. Slow IV, preferable IM. High availability. |
Benzylpenicillin |
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Broad-spectrum penicillin - much better absorption profile |
Amoxicillin |
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What facilitates the penetration of the outer membrane of Gram negative bacteria in broad - spectrum penicillins? |
Amino groups |
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B-lactamase resistant forms |
Flucloxacillin |
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Extended spectrum penicillins are also effective against... |
Pseudomonads |
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Reversed-spectrum penicillins (greater activity against Gram negative) |
Ticarcillin, piperacillin |
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Sulphonamides are... |
Bacterostatic |
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Sulphonamides selectively target |
Metabolic pathways, folate synthesis. |
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Example of Sulphonamide |
Trimethoprim |
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Broad spectrum class of antibiotic based on naladixic acid |
Fluoroquinolones |
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Most widely used Fluoroquinolone |
Ciprofloxacin (UTI treatment and also bacteremia cases) |
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Oral route - well absorbed in the upper GI tract |
Fluoroquinolones |
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Especially active against facultatives and aerobes |
Fluoroquinolones |
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Quinolones inhibit what enzyme in Gram negatives? |
DNA gyrase |
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Quinolones inhibit what enzyme in Gram positives? |
Topoisomerase |
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Some metabolism with mainly urinary excretion by both filtration and tubular secretion. |
Fluoroquinolines |
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Inhibitor of CYP1A2 |
Fluoroquinolines |
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May cause hypersensitivity and GIT disturbance |
Fluoroquinolines |
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Alternative to penicillin, bacteriostatic or -cidal |
Macrolides - streptogramins - erythromycin |
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Class of macrolides that are good against Gram positive cocci, especially penicillin resistant staphs, and anaerobes eg Bacteroides spp |
lincosamides - clindamycin |
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More recent macrolides, can be given by IV as well as orally. |
Azithromycin, Clarithromycin |
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Active against Gram positives and spirochaetes |
Macrolides |
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Target bacterial ribosomes and protein synthesis. Block translocation of the newly forming peptidebinds to site near RNA exit tunnelcauses peptidyl-transferase RNA drop-off |
Macrolides and lincosamides |
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Oral admin requires protected tablets to avoid inactivation by gastric juice |
Macrolides |
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Diffuses readily into most tissues but does not cross BBB. Crosses placenta. |
Macrolides |
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Metabolised by demethylation (CYP3A4). Can therefore potentiate the effects of other drugs. |
Macrolides |
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Excreted in the bile. |
Macrolides |
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Adverse reactions: Cholestatic hepatitis may occur after prolonged use of erythromycin estolate; GIT disturbances seen at large doses; transitory auditory impairment; hypersensitvity reactions |
Macrolides |
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Broad spectrum, bacteriostatic antibiotics |
Tetracyclins |
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Tetracyclins are administered... |
Orally |
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Examples of tetracyclins: |
Tetracycline, Doxycycline |
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Interrupts elongation phase of synthesisseveral binding sites on 30S RNA subunitsterically inhibits transfer RNA binding: unbinds, rebinds, futile loop |
Tetracyclins |
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Absoprtion greater in fasting state and inhibited by concurrent ingestion of dairy products metal ions and certain antacids |
Tetracyclins |
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Excreted both via the bile and in kidneys by glomerular filtration |
Tetracyclins |
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Relatively long half lives (6-18 hours due to enterohepatic recirculation) |
Tetracyclins |
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