Antimicrobial Therapy

Question 1

What is anesthesia’s role in antibiotic therapy?

Answer 1

The anesthetic provider plays an important role in timely administration of antibiotics
Contributes to our reimbursement for quality care

Question 2

What are potential adverse reactions from antibiotic therapy?

Answer 2

Hypersensitivity reaction
Direct organ toxicity
Potential for superinfection

Question 3

What is a common misconception regarding hypersensitivity reactions with antibiotics?

Answer 3

They are dose independent meaning you can give any amount (test dose or not) and still have a reaction

Question 4

Why do we give antibiotics prophylactically?

Answer 4

The surgeon exposes and transects parts of the body that have bacteria all the time
Exposing certain parts of the body to flora that is not normal in that area

Question 5

What antibiotic covers majority of the organisms we expose the body to?

Answer 5

Cefazolin

Question 6

What antibiotics should be used with caution in pregnancy?

Answer 6

Aminoglycosides (ototoxicity) and Clindamycin (colitis)

Question 7

What antibiotics are contraindicated in pregnancy?

Answer 7

Tetracyclines –> tooth discoloration in babies

Question 8

How are antibiotics categorized?

Answer 8

Bactericidal

Bacteriostatic

Question 9

What does it mean if an antibiotic is considered to have bactericidal properties?

Answer 9

It can kill the susceptible bacteria

Question 10

What does it mean if an antibiotic is considered to have bacteriostatic properties?

Answer 10

It reversibly inhibits growth of the bacteria

Question 11

If bacteriostatic drugs cannot kill bacteria how do they get rid of a bacterial infection?

Answer 11

They allow cellular and humoral defense mechanisms to eradicate the bacteria

Question 12

What type of antibiotics are penicillins?

Answer 12

Bactericidal

Question 13

What is the mechanism of action of penicillins?

Answer 13

They interfere with synthesis of peptidoglycans, which are components of bacterial cell wall

Question 14

What type of antibiotics are cephalosporins?

Answer 14

Bactericidal

Question 15

What is the mechanism of action of cephalosporins?

Answer 15

Inhibits bacterial cell wall synthesis by binding to one or more of the penicillin-binding proteins

Question 16

What class of antibiotics have the highest reported rate of allergy?

Answer 16

Penicillins (up to 10%)

Question 17

What two types of reactions are associated with penicillin allergy?

Answer 17

Delayed = maculopapular rash
Immediate = anaphylaxis

Question 18

Why is there a high likelihood of cross sensitivity between penicillins and cephalosporins?

Answer 18

They share a common beta-lactam ring

Question 19

What is a side effect of high dose penicillins?

Answer 19

Affect platelet aggregation

Question 20

What superinfections can result with cephalosporin use?

Answer 20

Enterococci
Enterobacter
Candida

Question 21

How many generations of cephalosporin drugs are there?

Answer 21

Four

Question 22

What type of antibiotic is Vancomycin?

Answer 22

Bactericidal for most gram positive bacteria

Question 23

What is the mechanism of action of Vancomycin?

Answer 23

Inhibits cell wall synthesis by inhibiting peptidoglycan synthetase

Question 24

What infections is Vancomycin typically reserved to treat?

Answer 24

MRSA
Endocarditis due to strep, viridans or enterococci
Patients allergic to beta lactams

Question 25

Why is it important to administer Vancomycin slowly?

Answer 25

To prevent a massive histamine leading to Red Man's Syndrome

Question 26

Why is it important to check the IV site prior to administering Vancomycin?

Answer 26

It is phlebosclerotic causing damage to the tissues if infiltration occurs

Question 27

What organ systems can Vancomycin affect?

Answer 27

Kidneys, nephrotoxicity when given with other nephrotoxic drugs Ototoxicity increased risk if giving with aminoglycosides

Question 28

What symptoms usually accompany Red Man Syndrome?

Answer 28

Profound hypotension | Flushing

Question 29

Why have aminoglycosides lost favor in patient administration?

Answer 29

It has an extensive list of significant side effects

Question 30

What kind of antibiotic is Gentamicin?

Answer 30

Bactericidal Aminoglycoside

Question 31

What side effects are typically seen with aminoglycoside use?

Answer 31

Ototoxicity Nephrotoxicity Muscular Weakness

Question 32

What drugs used in combination with aminoglycosides can increase the risk of ototoxicity?

Answer 32

Lasix | Mannitol

Question 33

What renal impairment are aminoglycosides known to cause?

Answer 33

Acute tubular necrosis

Question 34

What mechanism causes muscle weakness in aminoglycoside use?

Answer 34

Aminoglycosides inhibit the prejunctional release of Ach and decreases post-synaptic sensitivity Pre-exisitng musculoskeletal diseases may be potentiated by these efects

Question 35

How would aminoglycoside use impact administration of neuromuscular blockade?

Answer 35

Aminoglycosides are associated with potentiation of Non depolarizing NMBA Not effectively reversed by neostigmine

Question 36

What other anesthetic drug is affected by aminoglycosides?

Answer 36

Lidocaine, it enhances the neuromuscular blocking activities

Question 37

How would dose of NMBA be adjusted if the patient is currently taking aminoglycosides?

Answer 37

Decrease the amount given

Question 38

What class of antibiotics are useful in patients with allergies to PCN and cephalosporins?

Answer 38

Macrolides

Question 39

What two Macrolide antibiotics are commonly used?

Answer 39

Erythromycin | Azithromycin

Question 40

What is the most common complaint with Macrolide use?

Answer 40

GI intolerance

Question 41

How do Macrolides affect the GI tract?

Answer 41

Prokinetic effect on GI tract and increases the tone of the LES

Question 42

What effect do Macrolides have on the cardiovascular system?

Answer 42

Prolongs cardiac repolarization (prolong QT) | Can cause Torsades and sudden cardiac death

Question 43

What drug is most commonly used in female GU surgeries?

Answer 43

Clindamycin

Question 44

Why is Clindamycin's use so limited?

Answer 44

Severe GI complications limit its used to infections that are difficult to treat

Question 45

What other antibiotic has an affect on neuromuscular blockade?

Answer 45

Clindamycin, produces pre and post junctional effects at the NMJ that cannot be readily antagonized

Question 46

What ailments are fluoroquinolones useful in treating?

Answer 46

Respiratory infections GI upset Anthrax

Question 47

What type of antibiotics are sulfonamides?

Answer 47

Antimicrobial

Question 48

What is the mechanism of action of sulfonamides?

Answer 48

Prevent normal use of PABA by bacteria to synthesize folic acid

Question 49

What antibiotic is used most often in pediatric patients for ear infections?

Answer 49

Sulfonamides

Question 50

What is a negative effect of using sulfonamides?

Answer 50

High incidences of allergic reactions

Question 51

What is a virus?

Answer 51

Obligate intracellular parasites

Question 52

How do we target a virus without killing our own cells?

Answer 52

Some host cell surface receptors are unique for viruses and this gives a location for potential drug therapy

Question 53

What is Acyclovir used to treat?

Answer 53

Used to treat herpes

Question 54

What side effects can be seen with the use of Acyclovir?

Answer 54

May cause renal damage if infused rapidly Thrombophlebitis Headache

Question 55

If a patient reports being on triple therapy what disease process are they more than likely fighting?

Answer 55

HIV

Question 56

What are the six classes of HIV antiretrovirals?

Answer 56

``` Nucleoside/nucleotide reverse transcriptase inhibitors Protease inhibitors Fusion inhibitors CCR5 receptor antagonists Integrase inhibitors ```

Question 57

What should the anesthetic provider be assessing in the operative patient on triple therapy?

Answer 57

Existence of adverse effects (organ damage, neuropathy, weakness) Interactions with other medications (PPI and cimetidine) can affect CYP causing increased available medications leading to toxicity

Question 58

If a healthcare worker is exposed to HIV with a high viral load what precautions should be taken?

Answer 58

Prophylaxis with three or more antiretroviral drugs (two if the patient had a low viral load)

Question 59

How long should a healthcare provider be followed if exposed to HIV?

Answer 59

For at least six months after exposure

Question 60

When does most mother to child transmission of HIV occur?

Answer 60

At the time of labor and delivery (both mom and baby should receive AZT every six hours for six weeks after birth)

Question 61

What antiretroviral drug should the HIV positive mother receive after the first trimester of pregnancy?

Answer 61

AZT

Question 62

What microbial agents do first generation cephalosporins have the greatest effect on?

Answer 62

Strep pneumoniae Gram positives (little effect on gram negative)

Question 63

What microbial agents do second generation cephalosporins have the greatest effect on?

Answer 63

Equally effective against gram positive, gram negative and strep pneumoniae

Question 64

What microbial agents do third generation cephalosporins have the greatest effect on?

Answer 64

Gram negative Strep pneumoniae (little effect on gram positive)

Question 65

What microbial agents do fourth generation cephalosporins have the greatest effect on?

Answer 65

Gram negative Strep pneumoniae (moderate effect on gram positive)

Question 66

What other drug is almost always used in combination with aminoglycosides?

Answer 66

Almost always used along with a cell wall synthesis inhibitor

Question 67

What is the mechanism of action of aminoglycosides?

Answer 67

Irreversible inhibition of protein synthesis 30s (O2 dependent transport)

Question 68

What pregnancy category are aminoglycosides?

Answer 68

C

Question 69

What lab values should you base your dose of aminoglycosides on?

Answer 69

Creatinine | Serum concentration

Question 70

What is significant about azithromycins half life?

Answer 70

The half life is three days, 1g dose provides 7 days of coverage

Question 71

What is the mechanism of action of macrolides?

Answer 71

Bind to 50s and block translocation step in protein synthesis

Question 72

What type of antibiotics are macrolides?

Answer 72

Bacteriostatic

Question 73

How can macrolides affect metabolism of other drugs?

Answer 73

P450 Inhibitor, increasing the concentration of other drugs | Can also cause liver toxicity

Question 74

What type of antibiotic is Clindamycin?

Answer 74

Bacteriostatic

Question 75

If a sulfa allergy is present, what two drugs can be used to treat toxoplasmic encephalitis?

Answer 75

Clindamycin and pyrimethomine

Question 76

What two GI disturbances can occur with Clindamycin use?

Answer 76

Cdiff | Enterocolitis

Question 77

What is the mechanism of action of fluoroquinolones?

Answer 77

Inhibits DNA gyrase and topoisomerase

Question 78

What type of antibiotic are fluoroquinolones?

Answer 78

Bacteriocidal

Question 79

What pregnancy category are fluoroquinolones?

Answer 79

C

Question 80

What are some adverse effects of fluoroquinolone use?

Answer 80

``` Tendon rupture QT prolongation seizure Dizziness Confusion Photosensitivity ```

Question 81

Why shouldn't children under 18 take fluoroquinalones?

Answer 81

Interferes with cartilage formation

Question 82

How is cefazolin typically dosed?

Answer 82

Usually 1g, but increase to 2g when over 80kg