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Antimicrobials- Drugs & Bugs II - Updated
Pharm Assessment 13
55
Pharmacology
Graduate
02/09/2012

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Cards

Term
What cell wall inhibitor binds to the D-Ala-D-Ala terminus of nascent peptidoglycan pentapeptide?
Definition
Vancomycin
Term
How is resistance created against Vancomycin?
Definition
Alteration in the peptapeptide binding site
Term
What spectrum does Vancomycin have?
Definition
Narrow - primarily against G+
Staph aureus
S. epidermidis
Streptococcal endocarditis
Pseudomenbranous colitis
Term
What type of infections can Vancomycin be taken orally for?
Definition
GI infections
Term
What antibiotic can cause ototoxicity with high concentration or rapid infusion?
Definition
Vancomycin
Term
Risk of Nephrotoxicity increases with Vancomycin when co-administered with what drugs?
Definition
aminoglycoside
cyclosporin
Amphotericin
Term
What drug has an adverse effect of "Red man syndrome"? What is the syndrome?
Definition
Vancomycin

Histamine release, flushing, chills, fever
Vasodilation, low BP, patient collapse or shock
Term
What adverse effects occur in Myloma patients taking Vancomycin?
Definition
produce high IgA, binds and reduces vancomycin levels
Term
What are the 4 therapeutic uses of Vancomycin?
Definition
Serious infection
(not sensitive to less toxic agents)
MRSA
(switch to nafcillin if sensitivity)
Enterococcus for PCN allergy
(may co-administer aminoglycoside)
Pseudomembranous colitis - C. difficile
Term
What antibiotics treat Enterococci?
Definition
Linezolid
Term
What protein synthesis inhibitor binds to 23S RNA on 50 ribosomal subunit?
Definition
Linezolid
Term
What organisms is Linezolid bacteriostatic against? Bacteriocidal against?
Definition
Bacteriostatic - staphylocci and enterococci
Bacteriocidal - streptococci
Term
What are the FDA approved indications for Linezolid?
Definition
Both Enterococcus faecium and faecalis
MRSA and MR epidermidis
PCN-resistant S. aureus
Reserved for serious VRE infections
Term
How can Linezolid be administered?
Definition
Both oral and parenteral use

100% absorption of oral dose!!
Term
How does food affect the absorption of Linezolid?
Definition
Delays absorption, but not peak drug levels
Term
Why must the oral suspension of Linezolid be used with caution with phenylketonuria?
Definition
contains aspartame
Term
Why can Linezolid cause Hypertension?
Definition
from increased absorption of tyramine from the diet
Term
What is the Tetracycline antibiotic?
Definition
Doxycycline
Term
What is the general mechanism of action of the Tetracyclines?
Definition
Inhibits Protein Synthesis by reversibly binding 30S ribosome

Bacteriostatic

Enters cells by passive diffusion through porin channels
Term
What spectrum of bugs do Tetracyclines work against?
Definition
G+ and G- bacteria
(aerobic and anaerobic)
Mycoplasma
Chlamydia
Protozoa
Rickettsiae
Spirochetes
Term
Tetracycline may be the drug of choice for which organisms?
Definition
Mycoplasma
Chlamydia
Rickettsiae
Spirochetes
Term
How does resistance occur to Tetracyclines?
Definition
Occurs Slowly
Reduced transport of drug
Increased efflux from cell

Resistance to 1 Tetracycline provides resistance to All
Term
What inhibits Tetracyclines Absorption? How is it absorbed best?
Definition
Inhibited by di- and trivalent cations
(Ca++, Mg++, Fe+++, Al+++)

Absorbed best in acidic stomach - no antacids
Term
Where do tetracyclines concentrate in the body?
Definition
Liver
Kidney
Spleen
Tumors
Bone and Teeth when undergoing calcification
Term
How are the tetracyclines metabolised and excreted?
Definition
liver
Term
How are the tetracyclines primarily excreted?
Definition
glomerular filtration
Term
What adverse effects can occur in the GI from Tetracyclines?
Definition
Nausea, Vomiting, diarrhea
Avitaminosis
Superinfections
(changes in microbial flora can lead to candidiasis)
Term
What Tetracycline is least likely to cause superinfection problems? why?
Definition
Doxycycline
Its more cmopletely absorbed so doesn't disrupt the microbial flora
Term
Why should tetracyclines be avoided during gestation or to children <8 years old?
Definition
Chelation of Ca++
causes discoloration of teeth

Depression of bone Growth
Term
What tetracyline causes photosensitivity most frequently?
Definition
Doxycycline
Term
What are the therapeutic uses of Tetracyclines?
Definition
Lyme Disease (Borrelia Burgdorferi)
Rickettsia infection
Chlamydia
Mycoplasma
Certain types of periodontal disease
Acne
Term
What are the Macrolides/Ketolides?
Definition
Erythromycin
Clarithromycin
Azitromycin
Term
What is the Bacteriostatic action of Erythromycin?
Definition
Binds reversibly to 50S ribosomal subunit and inhibits protein synthesis
Term
Why is it important to maintain Erythromycin concentrations above MIC and insure patient compliance?
Definition
Bacterial resistance develops rapidly
Plasmid mediated

Decreased transport
Modification of ribosomal target by methylases
Hydrolysis or drug by esterases
Term
Where does Erythromycin concentrate in the body and how is it excreted?
Definition
Concentrates in Liver
(not metabolized)
Excreted primarily in bile and feces
Term
What is the 2nd choice after Penicillin G for G+ infections?
Definition
Erythromycin
Term
What G+ infections is Erythromycin indicated for?
Definition
Pneumoccocci or Group A Strep in PCN allergic patients
Listeria monocytogenes
Corynebacterium dephtheriae
Lyme Disease
**Used in Patients allergic to PCN**
Term
What G- infections is Erythromycin used for?
Definition
Legionnaire's Disease
Mycoplasma pneumoniae infections
Some chlamydia infections
Term
What is the drug of choice for Legionnaire's disease?
Definition
Erythromycin
Term
What is Chloestatic hepatitis associated with?
Definition
Erythromycin
Term
What P450 interactions does Erythromycin have?
Definition
Inhibits CYP450 enzyme

Increases concentrations of theophylline, warfarin, terfenadine, astemizole, carbamazepine, cyclosporine
Term
How does Clarithromycin compare with Erythromycin?
Definition
More acid stable than erythromycin
Oral dose Increases with food
Rapid First Pass metabolism
Eliminated by kidney and liver
Term
What therapeutic uses does Clarithromycin have increased activity with?
Definition
H. influenzae
Legionella pneumophila
Strep. Pneumoniae, S. pyogenes
Helicobacter pylori
Mycobacterium avium complex (DOC)
Chlamydia trachomatis
Moraxella catarrhalis
Term
What is the drug of choice for Mycobacterium avium complex?
Definition
Clarithromycin
Term
How are the Macrolids ordered by t1/2?
(erythromycin, clarithromycin, azithromycin)
Definition
Azithromycin - 35-40 hrs
Clarithromycin - 4 hrs
Erythromycin - 1.6 hrs
Term
How is Clarithromycins absorption dose effected by food? How is Azithromycin's?
Definition
Clarithromycins - Increased

Azithromycin - Decreased
Term
What macrolid concentrates in neutrophils, macrophages, and fibroblasts?
Definition
Azithromycin
Term
How is Azithromycin excreted?
Definition
In the Bile
Term
What macrolid is similar in effectiveness to penicillin V for pharyngitis and amoxicillin for sinusitis?
Definition
Azithromycin
Term
What is the drug of choice for Campylobacter, Legionella, and Mycobacterium avium complex?
Definition
Azithromycin
Term
What is the mechanism of Clindamycin?
Definition
Inhibits protein synthesis
Binds to 50S subunit of ribosome
Term
What is Clindamycin effective for? How does resistance develop?
Definition
Effective for anaerobes
(G+ organisms)

Resistance occurs slowly - stepwise
decreased affinity of drug for ribosome
Term
What antibiotic can penetrate bone but does not penetrate to CSF?
Definition
Clindamycin
Term
What antibiotic that binds 50S subunit can cause Pseudomembranous colitis?
Definition
Clindamycin

(from Clostridium difficile)
Term
What are the therapeutic uses for Clindamycin?
Definition
Bacteroides fragilis (outside CNS)
Prophylacsis for PCN allergic
Toxoplasmosis in AIDS- with pyrimethamine
Pneumocystis jiroveci pneumonia - with primaquine
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