Term
| What are the Aminoglycosides? |
|
Definition
Gentamicin
Tobramycin
Amikacin |
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Term
| How are Aminoglycosides Bactericidal in growing cells? |
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Definition
Transport across cytoplasmic membrane is energy dependent
Irreversible binds to 30S subunit |
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Term
| What is transport of aminoglycosides into the cell dependent on? How can it be blocked? |
|
Definition
Dependent on Electron Transport System
Displaces Mg++ on membrane
Transport blocked by divalent cations, hyperosmolarity, reduced pH or anaerobic conditions |
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Term
| What microbial enzymes can inactivated Aminoglycosides and cause resistance? |
|
Definition
Acetylase
Adenylase
Phosphorylase |
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Term
| T/F Resistance to one AMG provides resistance to all. |
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Definition
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Term
| What areas of the body are AMGs rapidly absorbed and can cause an unexpected toxicity? |
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Definition
Body cavities with serosal surfaces
Neuromuscular blockade |
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Term
| What areas of the body do AMGs not penetrate, and how can distribution be affected? |
|
Definition
Do No Penetrate Fatty Tissue or CSF (unless inflamed meninges)
Distribution affected by dehydration, congestive heart failure, peritonitis, edema |
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Term
| Where can higher concentrations of AMGs be found in the body? |
|
Definition
In cells with active transport mechanisms
Hair cells of ears
Tubular cells of renal cortex |
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Term
| How are AMGs blood levels effected by fever? |
|
Definition
| Decreased Blood levels due to increased glomerular filtration |
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Term
| How is the level of gentamicin affected by a hematocrit <25? |
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Definition
| Higher Serum levels then expected |
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Term
| What are the 3 main adverse reactions of Aminoglycosides? |
|
Definition
Ototoxicity
Nephrotoxicity
Neurotoxicity |
|
|
Term
| How is AMG Neurotoxicity treated? |
|
Definition
Ca++
Cholinesterase inhibitor - neostigmine |
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Term
| What organisms are treated with AMGs combined with a penicillin or cephalosporin? |
|
Definition
P. aeruginosa
Enterobacter
Klebsiella
Serratia |
|
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Term
| What organism does Gentamicin have more activity against? |
|
Definition
|
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Term
| What Bug is treated with Gentamicin combined with Pen G or ampicillin? |
|
Definition
| Enterococcus endocarditis |
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Term
| What combination with AMGs is used to treat MRSA and Staph. Epidermidis? |
|
Definition
| Gentamicin with Vancomycin |
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Term
| What bug is Tobramycin more active against? |
|
Definition
|
|
Term
| What 3 bugs does Amikacin have activity for? |
|
Definition
Klebsiella
Enterobacter
E. coli
(Strains resistant to gentamicin and tobramycin) |
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|
Term
| What 2nd line agents can be used to treat Mycobacterium tuberculosis? |
|
Definition
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|
Term
| How does Chloramphenicol inhibit protein synthesis? |
|
Definition
| by binding 50S ribosomal subunits |
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Term
| What is the most frequent mode of resistance to Chloramphenicol? |
|
Definition
Inactivation by enzymatic acetylation
Chloramphenicol acetyltransferase
G- bacteria acquire plasmid resistance gene by conjugation
Eliminates ability to bind to 50S subunit |
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Term
| How is Chloramphenicol distributed in the body? |
|
Definition
Most Body fluids
Enters CNS (up to 50% of blood level)
Crosses the placental barrier |
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Term
| What 2 ways is chloramphenicol Excreted? |
|
Definition
Glomerular filtration - unmetabolized
Tubular secretion - inactive metabolite |
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|
Term
| What antibiotic cause reversible inhibition of erythropoiesis? What does this cause? |
|
Definition
Chloramphenicol - Dose related (>25ug/ml)
Bone Marrow Depression |
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|
Term
| What type of anemia can be caused by Irreversible toxicity to bone marrow by Chloramphenicol? |
|
Definition
Aplastic anemia
Can develop months after discontinuation or from single dose |
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Term
| What is Gray Baby syndrome? What drug can cause this? |
|
Definition
Failure to feed, abdominal distension, progressive pallor, cyanosis, vasomotor collapse
Chloramphenicol |
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Term
| What drug can decrease the plasma concentrations of Chloramphenicol if co-administered? |
|
Definition
|
|
Term
| When should Chloramphenicol be used and against what organisms? |
|
Definition
For serious infections with susceptible bacteria that cannot be treated effectively with less toxic agents.
Hemophilus influenzae meningitis
Salmonella typhi
Bacteroides |
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Term
| What are the Sulfonamides? |
|
Definition
Sulfamethoxazole
Sulfisoxazole
Silver sulfadiazine
Sulfasalazine |
|
|
Term
| What antibiotics inhibit utiliation PABA in the synthesis of folic acid? |
|
Definition
|
|
Term
| What is the stepwise development of resistance to Sulfonamides? |
|
Definition
1) Alteration in enzyme requiring PABA
2) Increased inactivation of Drug
3) Alternative metabolic pathway
4) increased production of PABA |
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Term
| What Sulfonamides are Rapidly absorbed? |
|
Definition
Sulfamethoxazole
Sulfisoxazole
Sulfadiazine
Sulfacytine
Sulfamethizole |
|
|
Term
| What Sulfonamides are poorly absorbed? |
|
Definition
|
|
Term
| What Sulfonamides are topical formulations? |
|
Definition
Sulfacetamide
Silver sulfadiazine
Mafenide |
|
|
Term
| What Sulfonamide is Long-acting? |
|
Definition
Sulfadoxine
(t1/2 = 7-9 days) |
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|
Term
| What 5 adverse effects can Sulfonamides have? |
|
Definition
Crystalline aggragates in UT
Hematologic Disorders in G6PD def.
Hypersensitivity
Drug potentiation - Binds albumin displaces drugs
Renal and Liver damage |
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|
Term
| What Sufonamides are used for UTIs? |
|
Definition
Sulfamethoxazole
Sulfisoxazole |
|
|
Term
| What topical sulfonamide is used to treat susceptible infections of the eye? |
|
Definition
|
|
Term
| What Sulfonamide is used to treat Chronic inflammatory bowel disease? |
|
Definition
|
|
Term
| What antibiotic inhibits reduction of dihydrofolate to tetrahydrofolate? |
|
Definition
|
|
Term
| How do bacteria develop resistance to Trimethoprim? |
|
Definition
Alteration in enzyme affinity
G- have altered DHFR with lower affinity |
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Term
| What are the advantages to combining Trimethoprim and Sulfamethoxazole? |
|
Definition
Synergistic Activity
Low Toxicity |
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|
Term
| What adverse reactions are common for Bactrim especially in the elderly? |
|
Definition
|
|
Term
| What are the Therapeutic uses for Trimethoprim-Sulfamethoxazole? |
|
Definition
Uncomplicated UTI
(E. Coli, Salmonella typhi)
Genital infections
(N. gonorrhoeae, N. meningitidis)
Bacterial URI
(H. influenzae, Legionella pneumophilia)
Pneumocyxtis jiroveci
Nocardiosis |
|
|
Term
| What are the Fluoroquinolones? |
|
Definition
Ciprofloxacine
Ofloxacin
Enoxacin
Levofloxacin
Moxifloxacin
Gatifloxacin |
|
|
Term
| What antibiotics inhibit DNA synthesis by blocking bacterial DNA gyrase enzyme? |
|
Definition
|
|
Term
| Mutations in what part of the DNA gyrase enzyme causes resistance to Quinolones? |
|
Definition
|
|
Term
| What organisms is Quinolone resistance becoming more frequent? |
|
Definition
|
|
Term
| How is oral absorption of Quinolones decreased? |
|
Definition
With antacids containing Al+++ or Mg++
With dietary supplements containing Fe++ or Zn++ |
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|
Term
| What tissues in the body are there high levels of quinolones? What cells do they accumulate in? |
|
Definition
High Levels in:
Bone
Urine
Kidney
Prostactic Tissue
Accumulates in Macrophages and leukocytes |
|
|
Term
| What Quinolone does not produce adequate urine concentrations for UTIs? |
|
Definition
|
|
Term
| Why is it good that Quinolones accumulate in macrophages and leukocytes? |
|
Definition
| Effective against intracellular organisms - Legionella |
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|
Term
| What Quinolones can cause Prolongation of QT interval? |
|
Definition
The 3rd Generations:
Gatifloxacin
Moxifloxacin
Except NOT Levofloxacin |
|
|
Term
| What 3rd generation Quinolone does not cause QT prolongation? |
|
Definition
|
|
Term
| Why should Quinolones be avoided in pregnancy, nursing, and children <18? |
|
Definition
| articular cartilage erosion |
|
|
Term
| What Broad spectrum of organisms are Quinolones used to treat? |
|
Definition
G+ aerobic bacteria
-Legionella pneumophila
-Haemophilus influenzae
-Pseudomonas aeruginosa
G- enteric rods or cocci:
-E.coli
-Klebsiella pneumoniae
-Moraxella catarrhalis
-Niesseria gonorrhoeae
G+ and anaerobic bacteria
Mycoplasma
Chlamydia |
|
|
Term
| What is the Bactericidal mechanism of Fosfomycin? |
|
Definition
Inhibits phosphoenolpyruvate transferase
Inhibits cell wall synthesis |
|
|
Term
| What drug can be used for uncomplicated UTIs caused by Enterococci strains resistant to other drugs? |
|
Definition
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