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PCM Exam 1 > Antibacterials 4 > Flashcards

Antibacterials 4 Flashcards

1
Q

Route of administration of vancomycin:

A

slow IV infusion

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2
Q

Adverse effects of Vancomcyin

A
  • Red man/red neck syndrome which is a infusion related flushing over the face so just need to slow the infusion rate (not allergenic)
  • ototoxicity
  • nephrotoxicity
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3
Q

What is the clinical use of daptomycin

A

Created because bacteria became resistant to vancomycin → used tot rest resistant gram positive organisms include VRE and VRSA

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4
Q

Daptomycin cannot be used to treat ____________

A

Pneumonia; surfactant inactivates it

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5
Q

Mechanism of action of daptomycin

A

Unique: binds to cell membrane via Calcium dependent insertion of lipid tail → depolarization → K efflux → cell death

Unique mechanism allows for ↓ resistance against daptomycin

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6
Q

Adverse effects of daptomycin

A

Constipation, nausea, headache, insomnia

Also causes ↑ creatine phosphokinases which makes them at higher risk for myopathies

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7
Q

It is recommended to discontinue coadminstiation of _________ when taking daptomycin

A

Statins (due to ↑ creatine phosphokinases)

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8
Q

What is bacitracin used to treat and is there risk of resistance?

A

Gram positive organisms;
No cross resistance due to having a unique mechanism

Acts at late stage of cell wall synthesis

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9
Q

What is an adverse effect of bacitracin ?

A

Marked nephrotoxicity so must be given topically

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10
Q

Mechanism of action of fosfomycin and what kind of bacteria is it used against

A

Inhibits enolpyruvate transferase in the early stage of cell wall synthesis
Gram positive and gram negative

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11
Q

What condition is fosfomycin used to treat

A

Uncomplicated lower UTI’s

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12
Q

Protein synthesis inhibitors are mostly bacterio_________ and they target the bacterial ribosome _____S.

A

Static;

70S ( mammalian are 80S)

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13
Q

Drugs that are in the class of tetracyclines (3)

A

Doxycycline, minocycline, tetracycline

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14
Q

Mechanism of action of tetracycline and

A

Enter via passive diffusion and energy dependent transport which is unique to bacterial inner cytoplasmic membrane
Bind reversibly to 30S subunit of the ribosome and prevents attached of tRNA

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15
Q

Tetracyclines bind to ________

A

30S subunit of the ribosome

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16
Q

Tetracyclines are especially effective in treating conditions caused by __________ organisms

A

Intracellular organisms

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17
Q

What are the 3 main mechanisms of tetracycline resistance (plasmid encoded)

A
  • impaired influx or ↑ efflux by active (plasmid encoded) protein pump
  • production of proteins that interfere with binding to the ribosome
  • enzymatic inactivation
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18
Q

What are the conditions that tetracyclines are used to treat

A
  • most common: severe acne and rosacea
  • empiric therapy of community acquired pneumonia (outpatients)
  • atypical pneuma (mycoplasma, chlamydia and legionella)
  • treat syphillis patients who are allergic to penicillin for
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19
Q

________ decreases the GI absorption of tetracyclines

A

Calcium and other divalent and trivalent cations which will chelate the tetracyclines

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20
Q

What type of things should patients who are taking tetracyline avoid?

A

Milk/diary (calcium)

Antacids (magnesium)

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21
Q

____________ is a tetracycline that is lipid soluble and is preferred by parenteral administration

A

Doxycycline

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22
Q

_________ is a tetracyline that is used for STD’s and prostatitis

A

Doxycycline

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23
Q

Where can tetracyclines concentrate?

A

Liver, kidneys, spleen, and skin

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24
Q

Tetracyclines are primary excreted in the urine except for _______ which is excreted primarily by _______

A

Doxycycline; bile

25
Q

What are some adverse effects of tetracycline

A
  • Gastric effects/ super infections
  • discoloration and hypoplasia of teeth (calcium)
  • stunning of growth (teratogenic in pregnancy and should not be given to kids under 8 years old)
  • photosensitization
  • dizziness, vertigo (esp with doxycline and minocycline)
26
Q

Example of a glycylcycline drug and what is important about this family of drugs

A

Tigecycline

Similar to tetracyclines but with less resistance

27
Q

Route of administration of glycylcyclines

A

IV

28
Q

Primary route of elimination of glycylcyclines

A

Biliary/fecal

29
Q

What are the aminoglycoside drugs (5)

A 
Amikacin
Gentamicin 
Tobramycin
Streptomycin
Neomycin
30
Q

Aminoglycoside s are bateri______

A

Bactericidal;

Associated with serious toxicities

31
Q

Which class of protein synthesis inhibitors are bactericidal?

A

Aminoglycosides

32
Q

What is the difference between concentration dependent killing and time dependent killing of antibiotics

A

Concentration dependent: the amount of organisms that are killed is based on how high the peak concentration is
Time dependent: the amount of organisms killed is dependent on how long the drug concentration stayed above the MIC

33
Q

Unique pharmacodynamic features of amnioglycosides that allow it to be only given once daily

A

Post antibiotic effect + concentration dependent killing

34
Q

What is the mechanism of action of aminoglycosides

A
  • passive diffuses across membranes of gram NEGATIVE
  • actively transported (O2 dependent) across cytoplasmic membrane
  • covalently binds to 30S subunit and causes irreversible inhibition of the initiation complex → misreading of mRNA and blockade of translocation
35
Q

What are some of the consequences of the irreversible inhibition of the initiation complex in aminoglycoside

A

Misreading of mRNA and blockade of translocation

36
Q

Aminoglycosides are most active against _______ bacteria

A

Aerobic gram negative

37
Q

3 principle mechanisms of aminoglycoside resistance

A
  • Plasmid associated synthesis of enzymes that modify and inactivate drugs by: acetylation, phosphorylation and adenylation
  • ↓ accumulation of the drug
  • mutation can alter or delete the receptor protein on the 30S subunit
38
Q

_____________ (an aminoglycoside) is used for bowel surgery and hepatic encephalopathy

A

Neomycin

39
Q

What is aminoglycosides used to treat

A

Used mostly in combination
- empiric therapy for serious infections such as septicemia, nocosomial RTI, complicated UTI’s, endocarditis, etc

Once the organism is identified, aminoglycosides are usually discontinued to favor less toxic drugs

40
Q

Aminoglycosides are given ______ except for _______

A

Parenteral; neomycin which is given topically

41
Q

High levels of aminoglycosides are seen in _____ and _____

A

Renal cortex and inner ear

42
Q

Adverse effects of aminoglycosides

A
  • ototoxicity
  • nephrotoxicity
  • neuromuscular blockade in patients who have neuromuscular conditions such as Myasthenia
43
Q

In what conditions are aminoglycosides contraindicated with

A

Myasthenia gravis (and other similarly conditions) and pregnancy

44
Q

What drugs are used to treat hepatic encephalopathy and explain why

A
  • oral neomycin
  • lactulose
  • oral vancomycin
  • oral metronidazole
  • rifaximin

Drugs that are poorly metabolized in the gut are used to treat this and the encephalopathy is due to the ↑ NH4 (ammonia)

45
Q

Mechanism of action of how lactulose treats hepatic encephalopathy

A

Acidified the gut lumen which favors NH4 → NH3 and thus plasma ammonia concentrations are ↓

When lactulose is degraded by the intestinal bacteria, lactic acid is produced

46
Q

Effects of lactulose

A
  • treat hepatic encephalopathy
  • prebiotic: suppression of urase producing organisms
  • osmotically active laxative
47
Q

Macrolide family drugs: ( 4)

A

Erythromycin
Clarithromycin
Azithromycin
Telithromycin

48
Q

Macrolide are bacterio________ and are mainly used to treat gram ______ bacteria

A

Bacteriostatic; gram positive

49
Q

mechanism of action of macrolide

A

Reversibly binds 23S rRNA of the 50S subunit and blocks translocation

50
Q

3 Mechanisms of resistance for macrolides

A
  • reduced membrane permeability or active efflux
  • production of esterase that hydrolyze drugs (by enterobacteriase)
  • modification of ribosomal binding site by either mutation or methylation
51
Q

Macrolide drugs that have complete cross resistance:

3

A

Erythromycin, azithromycin, clarithromycin

52
Q

Macrolides are most active against gram _________ bacteria

A

Positive

53
Q

Clinical applications for Macrolides

A
  • community acquired pneumonia outpatient (combine with β lactam for inpatients)
  • atypcial pneumonia
  • upper respiratory tract and soft tissue infection
54
Q

_________ is the drug of choice for whooping cough

A

Erythromycin

55
Q

Macrolides is a common substitute for someone with ______ allergy

A

Pencillin

56
Q

Compare the pharmacokinetics of the macrolide drugs

A

Clarithromycin, azithromycin and telithromycin have improved oral absorption, longer half life, ↑ bioavailability, and broader spectrum than erythromycin

57
Q

__________, __________, and _________ are CYP 450 ___________ .

A

Erythromycin, clarithromycin, telithromycin

Inhibitors

58
Q

_________ is a macrolide drug that does NOT inhibit CYP 450

A

Azithromycin

59
Q

Contraindications for macrolides:

A
  • statins (macrolides inhibit CYP 450)

- do not use telithromycin for minor illnesses because it can cause fatal hepatotoxicity

PCM Exam 1 (22 decks)

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