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23 Cards in this Set
- Front
- Back
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Why do urinary tract antiseptics not have systemic activity?
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1) Rapid elimination
2) high protein binding 3) low pH in order to be effective |
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What are the three drugs listed in the notes for UTI?
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Nitrofurantoin
Methenamine Fosfomycin |
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What is the mechanism of action of nitrofurantoin?
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Largely unknown but probably forms reactive oxygen species
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What are the adverse effects of nitrofurantoin?
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Chronically- pulmonary fibrosis
acutely - cough, pulmonary infiltrates, GI upset, headache |
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What are some drugs that act on the cytoplasmic membrane?
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1) daptomycin
2) polymyxins (colistin, colistimethate, polymyxin B) |
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Describe how daptomycin works, and on what sort of organisms is it used?
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It's lipophilic tail inserts itself into the plasma membrane of the bacterium in a calcium dependent process which disrupts the membrane potential
It has good use against biofilms, MRSA, VRE, and VRSA |
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How do polymyxins work and on what organisms are they used?
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They penetrate cell membranes and interact with phospholipids, leading to disruption of the membrane
They are bactericidal against gram-negative aerobic bacilli |
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Why are polymyxins not often used?
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They are very nephrotoxic
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What is the mechanism of action of metronidazole? What organisms is it used to kill?
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They damage DNA
They are used to kill protozoa as well as anaerobic bacteria such as C. diff and B. fragilis, as well as used in triple therapy against H. pylori |
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What are the side effects of metronidazole?
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headache
disulfiram-like effects metallic taste |
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What drug is used as an alternative to treat N. gonorrhea in patients allergic to other drugs?
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spectinomycin
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What are the major drugs used in the treatment of TB?
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1) isoniazid
2) rifampin 3) ethambutol 4) streptomycin 5) pyrazinamide |
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Describe how active TB is treated
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It is always treated with multiply drugs (each with its own mechanism of action) to decrease the chance of resistant organisms developing
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What is used in the prophylaxis treatment of individuals that convert to TB+?
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Isoniazid
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What is the mechanism of action of isoniazid and what is required to active it?
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Isoniazid inhibits the synthesis of mycolic acids and a catalase/peroxidase is required for it's activation
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How is isoniazid metabolized and why is this important?
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Isoniazid is metabolized by acetylation in the liver
Slow acetylators have higher levels of isoniazid and are more prone to develop peripheral neuritis |
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What are the side effects associated with isoniazid?
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1) peripheral neuropathy
2) hepatotoxicity 3) B6 deficiency (which can lead to a B3 deficiency) |
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What is the mechanism of rifampin and what are the side effects?
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It inhibits the DNA dependent RNA polymerase
Side effects are 1) CYP450 induction 2) red/orange body secretions 3) hepatotoxicity |
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What side effect is associated with ethambutol?
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Dose related ocular toxicity including decrease in visual fields, loss of red/green color discrimination
It may precipitate gout |
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What are the adverse side effects of pyrazinamide?
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Hepatotoxicity and may provoke gout
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What is the only drug used to treat TB that must be injected?
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streptomycin, which is an aminoglycoside
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What are the drugs currently used to treat leprosy
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Dapsone
Clofazimine Rifampin |
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What is the mechanism of action of dapsone
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It is similar to sulfonamides and inhibits folic acid synthesis
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