PK/PD/Abx Mayo

Question 1

what are the highly bioavailable antimicrobials?

Answer 1

FQ, Fluconazole, voriconazole, metronidazole, linezolid, minocycline, doxycycline, bactrim, rifampin

Question 2

what is volume of distribution?

Answer 2

size of hypothetical compartment necessary to account for total amount of drug in the body as if it was present in the same concentration found in plasma. =amount of drug in body/measured peak plasma concentration

Question 3

A high volume of distribution means ??

Answer 3

distribute widely into tissues with low plasma concentration. typically lipophiillic like azithromycin

Question 4

a low volume of distribution means?

Answer 4

hydrophillic drugs with more blood than tissues.

Question 5

what are drugs typically hepatic metabolized?

Answer 5

macrolines, clindamycin, chloramphenicol, antifungals, rifampin, PI

Question 6

what are CYP3A inducers? clinical significance?

Answer 6

rifamycins, anticonvulsant agents - higher doses of concomitant medications needed.

Question 7

what are the CYP3A inhibitors? clinical significance?

Answer 7

Doses of concomitant medications needs to be decreased. Examples like macrolines, azole antifungals, CCB (diltiazem, verpamil)

Question 8

what does MIC mean?

Answer 8

lowest concentration that inhibits visible growth in vitro

Question 9

what is post antibiotic effect?

Answer 9

persistent suppression of bacterial regrowth after antibiotic is removed or levels decrease to below the MIC for the organism

Question 10

what abx illustrates post antibiotic effect?

Answer 10

typically that act by inhibiting protein/nucleic acid synthesis like macrolines, FQ, aminoglycosides. Beta lactams can do it against gram positive but not gram negative (exception is carbapenems against gram negative)

Question 11

what are the 3 factors that predictive of antimicrobial efficacy?

Answer 11

1. peak concentration to MIC ratio
2. AUC/MIC
3. T>MIC

Question 12

Parameters and drugs that exhibit concentration dependent killing?

Answer 12

Peak/MIC ratio; AUC/MIC ratio.

Aminglycosides, FQ, Metronidazole, amphotericin, Echinocandins, daptomycin, colistin

Question 13

parameters/drugs that exhibit killing without substantial PAE

Answer 13

T>MIC; penicillins, cephalosporins, carbapenems, vancomycin, clindamycin, macrolines, flucytosine

Question 14

parameters/drugs that exhibit time-dependent killing with moderate/prolonged PAE?

Answer 14

parameters: AUC/MIC, T>MIC; azithromycin, tigecycline, vancomycin, linezolid, tetracyclines, clindamycin, azoles, FQ, strepogramins

Question 15

what are the toxicities of penicillins?

Answer 15

all has hypersenitivity, GI, and phlebitis with IV therapy. High dose penicillin can cause seizures.

Question 16

Side effect special to ticarcillin?

Answer 16

hypernatremia, hypokalemia, platelet dysfunction

Question 17

Important thing to note about Zosyn?

Answer 17

neutroepnia with long term therapy, associated with false positive galactomannin antigen assays (aspergillus)

Question 18

mechanism of action for penicllins?

Answer 18

bind to penicillin binding proteins of cell wall, inhibiting x linking

Question 19

toxicities associated with carbapenems?

Answer 19

GI side effects, hypersensitivity reactions, drug fever, and overgrowth of resistnat organisms (yeast, stenotrophomas, C.Diff), seizures

Question 20

toxicities of aminoglycosides?

Answer 20

reversible nephrotoxicity, irreversible auditory toxicity, A and rarely neurmuscular bloackade

Question 21

what’s good about minocycline?

Answer 21

active against MRSA for mild disease in patients who cannot tolerate vanc, stenotrophomas, and mycobacterium marinum. Good against intracellular stuff

Question 22

Mechanism of action of triazoles?

Answer 22

inhibit ergosterol synthesis and cell membrane formation

Question 23

what’s the general spectrum of activity for fluconazole?

Answer 23

active against many candida species, cryptococcus, coccidiodes immitus. Alternative agent against histo/blasto. Less activity against glabrata, inactive against krusei

Question 24

general spectrum for itraconazole?

Answer 24

active against some fillamentous fungi (aspergillus, sporothrix, pseudallescheria, alternaria) with similar activity against candida. DOC for histo and blasto

Question 25

general specturm for voriconazole?

Answer 25

active against fillamentous fungi, active against most strains of candida, coccidiosis, cryptococcus, histo and blasto.

Question 26

general spectrum for posaconazole?

Answer 26

similar to voriconazole (filamentous, candida, crypto, coccidiosis, histo, blasto) but also add activity against zygomycetes

Question 27

Toxicities for triazoles?

Answer 27

all eelvate LFTs,prolong QT, Vori - rash + visual disturbances), Itraconazole is a negative inotrope (do not use in CHF)

Question 28

MOA of polyenes?

Answer 28

amophotericin bind to ergosterol in cell membrane and causes cell damange by increasing permeability and allowing efflux.

Question 29

spectrum of activity for polyenes?

Answer 29

yeasts, dimorphic fungi, filamentous fungi. less activity against aspergillus terreus, variable activity against aspergilus flavus, zygomycetes, and dematiaceous molds.

Question 30

toxicity of amphotericin?

Answer 30

infusion related (pre-treat), reversible nephrotoxicity, hypokalemia, hypomagnesemia, anemia,CNS. releases n slowly from peripheral tissues

Question 31

MOA of echinocandins?

Answer 31

inhibit 1,3b-d-glucan synthesis (cell wall inhibitor)

Question 32

spectrum of activity of echinocandins?

Answer 32

active against candida species including most azole resistant, aspergillus. Not active against cryptococcus, zygomyctes