Anti-infectives part 2

Question 1

Which antibiotics demonstrate gram + sensitivity?

Answer 1

gramicidin, macrolides, vancomycin, bacitracin

Question 2

what are 2 types of concentration dependent antibiotics?

Answer 2

aminoglycosides and fluoroquinolones

Question 3

which 3 antibiotics should you not take with food?

Answer 3

“PAT an empty stomach” = penicillins, azithromycin and tetracyclines

Question 4

would you give cephalosporins to a hemophilic patient?

Answer 4

no - cephalosporins cause vitamin K deficiency which is important for blood clotting

Question 5

what is the IV drug of choice for MRSA, MRSE and bacterial endophthalmitis?

Answer 5

Vancomycin

Question 6

what drug combo is used most commonly for pediatric ocular infections?

Answer 6

Polymyxin B + Trimethoprim

Question 7

Aminoglycosides and tetracyclines act by binding to and inhibiting which ribosomal subunit?

Answer 7

30S

Question 8

which drugs inhibit 50S ribosomal subunit?

Answer 8

macrolides and chloramphenicol

Question 9

which aminoglycoside has a class B pregnancy rating?

Answer 9

Tobramycin (tobradex)

Question 10

Pseudotumor cerebri is associated with which specific aminoglycoside?

Answer 10

gentamicin

Question 11

which are the most common aminoglycosides that can cause a type 4 delayed hypersensitivity reaction?

Answer 11

all 3 = gentamicin, tobramycin, neomycin

Neomycin is most common

Question 12

which tetracycline do we use most commonly to treat eyelid/meibomian gland conditions?

Answer 12

doxycycline (except in children = AzaSite)

*chlamydia, meibomianitis/meibomian gland stasis, acne rosacea

Question 13

when prescribing a tetracycline, what types of food should they avoid eating?

Answer 13

dairy products (binds to divalent calcium which renders the antibiotic dysfunctional)

Question 14

Fanconi’s syndrome is associated with which type of drugs?

Answer 14

tetracyclines

Question 15

which macrolides would you consider one of the safest antibiotics?

Answer 15

erythromycin and azithromycin = pregnancy class B ratings

Question 16

which macrolide is “ok” for pregnancy and infants?

Answer 16

azithromycin

Question 17

what type of patients should you be cautious to in giving macrolides?

Answer 17

asthmatics = macrolides augment plasma levels of theophylline

Question 18

why should you be cautious in giving chloramphenicol to newborns?

Answer 18

grey baby syndrome

Question 19

is trimethoprim a sulfa drug?

Answer 19

no = folic acid inhibitor

Question 20

do sulfa drugs work well in highly mucopurolent environments?

Answer 20

no = there is excessive PABA in discharge

Question 21

which topical drug is 1st line of treatment for MRSA with 95% efficacy? what is 2nd?

Answer 21

trimethoprim

tobramycin

Question 22

what folic acid inhibitor combo do you use to treat toxoplasmosis?

Answer 22

sulfadizine + Pyrimethamine

Question 23

what is a common adverse reaction of trimethoprim?

Answer 23

TMP = treats marrow poorly

bone marrow suppression

Question 24

your patient is allergic to BAK - but you need to treat their infection, which drug would you use?

Answer 24

moxifloxacin

Question 25

which drug does not exhibit bacterial resistance?

Answer 25

besifolxacin with durasite = no systemic predecessor

Question 26

tendinitis is an adverse reaction of which class of drugs?

Answer 26

fluoroquinolines

Question 27

which ocular antibiotic is least resistant to gram + infections?

Answer 27

trimethoprim/polymyxin B and besifloxacin

Question 28

which drugs are best for treating pseudomonas infections?

Answer 28

fluoroquinolones, aminoglycosides, polymyxin B

Question 29

what is the 1st line of therapy for recurrent HSV1 and HSV2 keratitis?

Answer 29

trifluridine (viroptic) - may be combined with oral acyclovir therapy

Question 30

your patient presents with acute herpetic keratitis (dendritic ulcers) - what drug will you prescribe?

Answer 30

Ganciclovir (Zirgan) - caution with cross-resistance with acyclovir

Question 31

what type of ocular involvement would you see in a patient with fungi?

Answer 31

cornea, conjunctiva, lens, CB, vitreous body and uvea

Question 32

what percentage of acanthamoeba keratitis cases are associated with CL wear > trauma?

Answer 32

85-95%

Question 33

what is the life-cycle of acanthamoeba?

Answer 33

trophozoites cysts

Question 34

which organism accounts for 50% of ocular infections (is it gram + or -)?

Answer 34

staphylococcus - gram +

Question 35

polymyxin B attacks what part of the cell and what gram type is it for?

Answer 35

cell membrane - gram negative

Question 36

which class of antibiotics attack the cell's DNA production?

Answer 36

fluoroquinolones

Question 37

which drug class irreversibly inhibits protein synthesis?

Answer 37

aminoglycosides

Question 38

all tetracyclines should not be taken with food except which one?

Answer 38

doxycycline

Question 39

which drug class and specific drugs can treat acne rosacea?

Answer 39

tetacyclines (doxycycline and minocycline)

Question 40

what is the only tetracycline that you should take if you have malfunctioning kidneys?

Answer 40

Doxycycline

Question 41

which gram + antibiotic is the only one that permits QD dosing?

Answer 41

AzaSite (azithromycin)

Question 42

which fluoroquinolone can cause white corneal precipitates?

Answer 42

ciprofloxacin

Question 43

which antifungals do not cause hepatotoxicity?

Answer 43

echinocandins (metabolized by liver enzymes) and amphotericin B (but toxic to kidneys)

Question 44

chronic antibiotic therapy can pre-dispose patients to what type of infection?

Answer 44

fungal

Question 45

name the fungi that may attack the eye and what can make it worse?

Answer 45

canidida, crytococcus, aspergillus, fusarium, and curvularia | CL's, steriods, trauma, immunocompromise