Antimicrobials

Question 0

Which is dose-related, having a hypersensitive reaction or having issues with toxicity?

Answer 0

Toxicity has to do with dose (too much)

Hypersensitive (allergic) reaction does not depend on dose

Question 1

When are surgical prophylactic antibiotics given?

Answer 1

Less than one hour before surgery

Question 2

Is ampicillin or amoxicillin more likely to be given by mouth? Which of these drugs has a higher incidence of skin rash?

Answer 2

Amoxicillin is given by mouth more because it is more efficiently absorbed from the GI tract
Ampicillin has a highest incidence of skin rash among penicillins, used for H flu and E coli
**Note: these are both broad-spectrum, second generation penicillins

Question 3

Are penicillins bactericidal or bacteriostatic? What organisms do they work against? How is it excreted?

Answer 3

Bactericidal
Penicillin against pneumococcal, meningococcal, streptococcal (gram pos), second generation against gram neg
Renal excretion

Question 4

Adverse reactions to penicillins?

Answer 4

Hypersensitivity (more than the other antimicrobials)

Cross sensitivity between penicillin and cephalosporins (this is due to the beta-lactam ring in both)

Question 5

Cephalosporin: broad or narrow spectrum? bacteriostatic or bactericidal? How is it excreted?

Answer 5

Broad spectrum
Bactericidal
Renal excretion
3 generations: 1-cefazolin (ancef), 2-cefoxitin, 3-cefotaxime

Question 6

Adverse reactions of cephalosporins?

Answer 6

Allergic reactions (rash)
Cross sensitivity between cephalosporins and penicillin

Question 7

Why are cephalosporins used in orthopedic surgery?

Answer 7

They penetrate into the joints

Question 8

Are aminoglycosides bactericidal/ bacteriostatic? Which organisms are they effective against? How is it excreted?

Answer 8

Bacteriocidal
Gram neg bacteria.. Narrow!
Renal excretion

Question 9

What are side effects of aminoglycosides?

Answer 9

Ototoxicity: irreversible vestibular/cochlear destruction over time
Nephrotoxicity: reversible, accumulation in renal cortex can cause tubular necrosis (neomycin #1 nephrotoxic, monitor BUN/creatinine)
Skeletal muscle weakness: inhibit ACh release (myasthenia gravis are sensitive), also issue with reversing muscle relaxant, calcium can help
Prolongs neuromuscular blockade: potentiated, reappears in PACU

Question 10

Why should use of Streptomycin and Kanamycin (aminoglycosides) be limited?
Why should plasma concentrations of Gentamycin by monitored?

Answer 10

Increased occurrence of vestibular damage with Streptomycin and Kanamycin
Gentamycin becomes toxic over 9 mcg/mL

Question 11

Which aminoglycoside is used for hepatic comas? Hint: this is also the aminoglycoside that is most nephrotoxic.

Answer 11

Neomycin

Question 12

Tetracyclines: Bactericidal or bacteriostatic? Uses? Where excreted?

Answer 12

Bacteriostatic
Used for acne treatment (decreases fatty acid content of sebum)
Excreted in urine and bile

Question 13

Side effects of tetracyclines?

Answer 13

Permanent discoloration of teeth

Phototoxicity

Question 14

Macrolides (Erythromycin/Zithromax): bacteriostatic or bactericidal? Broad or narrow spectrum? How is it metabolized/excreted?

Answer 14

Can be bacteriostatic or bacteriocidal (by inhibiting protein synthesis)
Narrow spectrum against gram +
Metabolized by cytochrome P-450 (smooth ER of liver), excreted by bile (so no need to alter dose for renal disease patients)

Question 15

Macrolides (Erythromycin) adverse effects?

Answer 15

GI intolerance: N/V
increased gastric emptying
QT effects: prolongs cardiac repolarization, increased incidence of torsades de pointes
Thrombophlebitis

Question 16

Lindomycins (Clindamycin): bacteriostatic/ bactericidal? Uses? Should dose be decreased for renal or liver disease?

Answer 16

Bacteriostatic
Used for serious infections in GI tract or female genital tract
Decrease dose with severe liver disease (metabolized in liver), elimination is only slightly prolonged with renal disease so this doesn’t require dose adjustment

Question 17

Clindamycin side effects?

Answer 17

Pseudomembranous colitis (severe diarrhea), when patient gets diarrhea, this med should be discontinued
Pre and post junctional effects at neuromuscular junction, not antagonized with anticholinesterases or calcium (not effective when reversing neuromuscular blocker), extended time of neuromuscular blockade

Question 18

Vancomycin: bactericidal/bacteriostatic? What organisms is it effective against? Excretion?

Answer 18

Bactericidal
Effective against gram positive bacteria, staph infections, streptococcal/ enterococcal endocarditis.. Narrow!
Drug of choice against MRSA
Renal excretion, (extremely prolonged elimination with renal failure, check vanco levels)

Question 19

Vancomycin surgeries?

Dose?

Answer 19

cardiac procedures
Orthopedic procedures with prosthetics
CSF and shunt infections
Dose: 10-15 mg/kg over 60 min (usually 1g/h), 1 gram mixed in 250 mL

Question 20

Which two drugs are used in many surgical procedures when a patient has a beta-lactam allergy?

Answer 20

Clindamycin or vancomycin

Question 21

Vancomycin side effects?

Answer 21

Rapid infusion can cause profound hypotension/ cardiac arrest
Red man syndrome (histamine release)
Ototoxicity
Nephrotoxicity
Return of neuromuscular blockade noted rarely

Question 22

Sulfonamides: bacteriostatic/ bactericidal? Uses? Metabolism/excretion?

Answer 22

Bacteriostatic
Used for UTIs
Hepatic metabolism
Renal excretion

Question 23

Sulfonamides side effects?

Answer 23

Rash to anaphylaxis
Drug fever
Hepatotoxicity
Acute hemolytic anemia
Increased effect of po anticoagulants

Question 24

Polymyxin B and Colistimethate: Bacteriostatic/ bactericidal? Uses? Elimination?

Answer 24

Bactericidal Effective for gram negative bacteria: UTI's, infections of skin, mucous membranes, eyes, ears.. Narrow! Eliminated by kidneys (accumulation in renal failure)

Question 25

Polymyxin B and Colistimethate: side effects?

Answer 25

Most potent antimicrobial at the neuromuscular junction (can produce skeletal muscle wekaness like a nondepolarizing neuromuscular blocker, neostigmine or calcium don't antagonize this drug) Highly nephrotoxic

Question 26

Metronidazole (flagyl): bacteriostatic/ bactericidal? What organism does it work against? Uses?

Answer 26

Bactericidal Anaerobic Gram negative bacilli Useful for CNS, abdominal, pelvic, and pseudomembranous colitis

Question 27

Fluoroquinolones (Ciprofloxacin, Moxifloxacin): broad or narrow spectrum? Bacteriostatic/ bactericidal? Uses? Excretion?

Answer 27

Broad spectrum, enteric against gram neg bacilli Bactericidal Used for GI/GU infections, Ciprofloxacin is useful in treating bone, soft tissue, and respiratory infections Excreted by renal, can inhibit P450, E1/2t is 3-8 hours

Question 28

Fluoroquinolones side effects?

Answer 28

Minimal (this is why it is used for GI/GU infections)

Question 29

Rifampin: Bacteriostatic/ bactericidal? Uses? Which organisms does it fight against? Excreted?

Answer 29

``` Bactericidal for mycobacteria TB drug Gram positive and some gram negative.. BROAD spectrum Excreted in bile/urine Note: fat soluble, travels to CNS ```

Question 30

Rifampin side effects?

Answer 30

Infrequent, in high doses: thrombocytopenia, aneia, hepatitis, fatigue, numbness, skeletal muscle weekness, induces P450 which will metabolism drugs (opioids, NM blockers, warfarin) quicker

Question 31

Amphotericin B: what class? Given IV or po? How is it excreted?

Answer 31

Antifungal Given IV Slow renal excretion (impairs functioning in 80% of patients, monitor BUN/creatinine)

Question 32

Antifungal side effects?

Answer 32

``` Fever, chills, dyspnea, hypotension during infusion Impaired hepatic and renal function Allergic reaction Seizure Anemia, thrombocytopenia ```

Question 33

Are viruses intracellular or extracellular parasites? Why does this make it difficult to treat?

Answer 33

Intracellular parasites, hard to treat because you must kill your own cells to kill the virus Viruses are composed of a nucleic acid core surrounded by a protein containing outer coat, genome has RNA or DNA, but never both

Question 34

Uses for Acylovir and valacyclovir?

Answer 34

Antiviral for herpes viruses

Question 35

Uses for Vidarabine?

Answer 35

Cytomegalic inclusion disease, herpes simplex encephalitis | Mutagenic and carcinogenic

Question 36

Uses for famciclovir?

Answer 36

Acute herpes zoster

Question 37

Uses for Ganciclovir?

Answer 37

Cytomegalovirus disease | Caution: hematologic toxicity

Question 38

Uses for Amantadine?

Answer 38

Influenza A or parkinsons

Question 39

How do Interferons work, what viruses can they be used for?

Answer 39

They bind to receptors on host cell to induce the production of enzymes that will inhibit replication, this will degrade viral mRNA. They also enhance tumoricidal activities of macrophages Used for chronic Hep B, Hep C

Question 40

Interferon side effects?

Answer 40

Flu like symptoms, depression, irritability, decreased concentration Hematologic toxicity (leukopenia, get a CDC) Development of autoimmune conditions Rashes, alopecia Changes in CV, thyroid, hepatic functioning

Question 41

What are some HIV antivirals?

Answer 41

NRTIs: are imposters, the look like fake human cells NNRTIs: inhibit enzyme function of virus (Nuclease/Non-nuclease reverse transcriptase inhibitors) Protease inhibitors: bind to HIV protease

Question 42

What are side effects of HIV antivirals?

Answer 42

``` Many, varied responses Pancreatitis, hepatotoxicity, lactic acidosis, fat redistribution, increased cholesterol and TAGs, hypersensitivity Protease inhibitors (especially Ritonavir) inhibit P450 system (prolonging action of many drugs) ```

Question 43

Which antimicrobials are bacterioSTATIC?

Answer 43

``` SECT.. Sulfonamides Erythromycin (macrolides).. both static and cidal Clindamycin Tetracycline ```

Question 44

Which antimicrobials prolong neuromuscular blockade?

Answer 44

``` PACC.. Polymyxin B Aminoglycosides Clindamycin Colimethate ```