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20 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Name sulphonamides
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Sulfamethoxazole, sulfadiazine, sulfadoxine, sulfasalazine
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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Name diaminopyrimidines
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Trimethoprim, pyrimethamine
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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What is Bactrim and what is its use?
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Combination of sulfamethoxazole and trimethoprim.
Used against bacteria and pneumocystis. |
68. Fluoroquinolones Sulphonamides and trimethoprim.
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Why do we combine sulphoamides and diaminopyrimidines?
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They are old drugs, so resistance is widespread since bacteria have changed surface proteins, decreasing the entry of the drug. We can overcome the resistance by combining them. Also, they have synergistic effects.
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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What is the mechanism of action of sulphoamides?
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They inhibit dihydropteroate synthase (DHPS), an enzyme essential for bacterial folic acid synthesis by mimicing the substrate. Bacteria cannot take up folic acid, so this will inhibit their DNA synthesis.
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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What is the mechanism of action of diaminopyrimidines?
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They inhibit dihydrofolic acid reductase, which converts DHF into THF, inhibiting DNA synthesis.
(Humans have same enzyme, but it has different structure than the bacterial. Methotrexate is used in humans) |
68. Fluoroquinolones Sulphonamides and trimethoprim.
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Pharmacokinetics of sulphoamides and diaminopyrimidines?
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All except sulfadiazine are given orally. They have excellent distrubution, especially into lungs, across BBB and placenta. Bind strongly to plasma proteins.
Most of them are metabolized in the liver and excreted by kidneys. The combined drugs have similar half-life. |
68. Fluoroquinolones Sulphonamides and trimethoprim.
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Side effects of sulphoamides?
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- Allergic reactions (skin rash, photosensitivity)
- Glomerulonephritis - Steve-Johnsons syndrome (very rare) - Crystalluria - Hemolytic anemia in people with G6PD deficiency - Kernicterus in infants. |
68. Fluoroquinolones Sulphonamides and trimethoprim.
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Side effects of diaminopyrimidines?
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Similar to folic acid deficiency:- Megaloblastic anemia- Leukopenia- Granulocytopenia.
Can be avoided by supplementation of leucovorin. |
68. Fluoroquinolones Sulphonamides and trimethoprim.
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Contraindications for suphamides and diaminopyrimidines?
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Last trimester of pregnancy and first weeks of life.
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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Name 1st generation flouroquinolones
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Norfloxacin
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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Name 2nd generation flouroquinolones
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Ciprofloxacin, ofloxacin
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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Name 3rd generation flouroquinolones
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Levofloxacin
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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Name 4th generation flouroquinolones
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Moxifloxacin, gemifloxacin
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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What is the mechanism of action of flouroquinolones?
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They inhibit DNA topoisomerase II (DNA gyrase) and DNA topoisomerase IV.
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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Pharmacokinetics of flouroquinolones?
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Most of them have 100 % bioavailability and can be taken orally. Some can be given as IV also.
They distribute widely into extra and intracellular space, but do not penetrate CNS. Ciprofloxacin and norfloxacin are eliminated party by liver and are partly excreted unchanged by renal excretion, making them good for treating urinary tract infection. |
68. Fluoroquinolones Sulphonamides and trimethoprim.
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What are the adverse effects of fluoroquinolones on the environment?
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They have the largest ecological shadow of all antibiotics because they have wide antibacterial spectra, are excreted unchanged by the kidneys and are poorly degraded by the environment. They remain in the environment for a long time, and increase the risk of bacteria becoming resistant.
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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Side effects of fluoroquinolones?
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- Contraindicated in pregnant women and children due to damage to growing cartilage.
- Tendinitis - Tendon rupture, can occur even months after treatment. - QT prolongation - Neuropathies - Depression - Aortic dissection. |
68. Fluoroquinolones Sulphonamides and trimethoprim.
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When do we use fluoroquinolones?
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Used in acute bacterial sinusitis, acute exacerbation of chronic bronchitis and uncomplicated UVIs if nothing else is available.
Their use should be limited due to their eco-shadow. |
68. Fluoroquinolones Sulphonamides and trimethoprim.
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Which tetracyclines can give more GI symptoms?
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Tetracyclines and oxytetracycline
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68. Fluoroquinolones Sulphonamides and trimethoprim.
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