Anti Infectives part 2

Question 1

Sulfanomides compete with _____

Answer 1

PABA

Question 2

Sulftanomides are combined with _____ in a 5:1 ratio.

Answer 2

Trimethoprim

Question 3

What is involved in the inhibition of dihydropteroate synthase

Answer 3

PABA doesn’t convert to DHF

Question 4

What is involved in the inhibition of dihydrofolate reductase

Answer 4

DHF doesn’t covert to THF

Question 5

Polytrim solution (polymyxin B + trimethoprim) as well as sulfadiazine and ______ are drugs used together to treat taxoplasmosis and are folic acid inhibitor combos

Answer 5

pyrimethamine

Question 6

____ is first line treatment for MRSA with 95% efficacy

Answer 6

Trimethoprim

Question 7

What are folic acid inhibitor adverse reactions

Answer 7

1. Hypersensitivity

2. Blood dycrasias

Question 8

What are folic acid inhibitor adverse reactions for sulfonamides

Answer 8

1. Stevens Johnson syndrome
2. Nephrotoxicity
3. Coumadin potentiation
4. Myopia +/- astigmatism (reverible)
   * Contraindicated in pregnancy!

Question 9

What are folic acid inhibitor adverse reactions for trimethoprim

Answer 9

bone marrow suppression

*contraindicated in pregnancy!

Question 10

______ are DNA synthesis inhibitors

Answer 10

Fluoroquinolones

Question 11

Fluoroquinolone’s are bactericidal and inhibit DNA gyrase and _____

Answer 11

topoisomerase IV

Question 12

____ is the only fluoroquinolone that is a topical suspension and is a 5th generation flouroquinolone

Answer 12

Besifloxacin

Question 13

____ and ____ are 2nd generation fluoroquinolones.

Answer 13

Ciprofloxacin and ofloxacin

Question 14

____ is a 3rd generation fluoroquinolone

Answer 14

Levofloxacin

Question 15

_____ and ___ are fourth generation fluoroquinolones

Answer 15

moxifloxacin and gatifloxacin

Question 16

What are fluoriquinolone adverse reactions

Answer 16

1. phototoxicity
2. tendinitis
3. reduced levels in combinations w antacids, Fe, and Zn
4. convulsions (pO)
5. ciprofloxacin –> white corneal precipitates, reduced metabolism of theophylline

Question 17

what are contraindications of fluoroquinolone

Answer 17

1. less than 18 yoa (pO) due to inhibition of bone growth and damage to cartilage.
2. pregnancy

Question 18

The best topicals for treating psudomanas infections are fluoroquinolones, aminoglycosides and ______

Answer 18

polymyxin B

Question 19

What are the best ocular ab’s for children

Answer 19

1. trimethorpim/polymyxin B

2. AzaSite

Question 20

What are the best ocular Ab’s for adults

Answer 20

1. Mild: Bacitracin/polymyxin B
2. Moderate: Neomycin
3. Tobramycin
4. Severe: Besifloxacin or Levofloxacin

Question 21

The dilemma to combine an antimicrobial agent and steroid depends on all of the following:

Answer 21

1. oval shaped processes at/near the limbus are inflammatory
2. severity of infection relative to conjunctival injection
3. Is the corneal epithelium intact?
4. Does pt test positive for lymphadenopathy

Question 22

When choosing Antibiotics select drugs with the _____ spectrum and use ____ agents whenever possible so we don’t make them susceptible to resistance

Answer 22

narrowest; older

Question 23

Viruses only replicate upon entering cells. They need a _____.Cells that host viral particles may experience collateral damage when antiviral agents are used. Viral ____ affects antiviral drug therapy efficacy

Answer 23

host; mutation

Question 24

_____ is a cold virus that is the most common cause of an eye infection. There is currently no FDA approved treatment for this type of infection and it is self resolving.

Answer 24

adenovirus

Question 25

If patient comes in your office and they have AIDs ask about:

Answer 25

1. viral load | 2. T cell count

Question 26

Pyrimidines inhibit thymidine synthesis. _____ is a pyrimidine analog and is used for HSV keratitis. There is risk of keratopathy, elevated IOP, lid and stromal edema and it is Pregnancy Category ______

Answer 26

Trifluridine; C

Question 27

What are the purine analogs that are used

Answer 27

1. Acyclovir (Preg category B) 2. Ganciclovir (Preg category C 3. Famciclovir 4. Valcyclovir

Question 28

Both acyclovir and ganciclovir have oral risk of ____ ____

Answer 28

blood dycrasias

Question 29

Famciclovir has an extended plasma life and Valcyclovir has an long plasma _____ life and is better suited for deeper infections such as stromal keratitis. Cross sensitivity seen with _______

Answer 29

half; Acyclovir

Question 30

_____ is drug of choice for HS keratitis therapy due to lower dosing frequency

Answer 30

Famciclovir

Question 31

What is the ocular involvement with fungal infections

Answer 31

1. cornea 2. conjunctiva 3. lens 4. ciliary body 5. vitreous body 6. uvea

Question 32

Which yeasts are involved ocularly

Answer 32

1. Candida | 2. Cryptococcus

Question 33

Which molds are involved ocularly

Answer 33

1. aspergillus 2. fusarium 3. curvularia

Question 34

What causes enhanced risk of fungal infection

Answer 34

1. contact lens wear 2. steroids 3. trauma 4. immunocompromise

Question 35

What are therapeutic concerns of fungal infections

Answer 35

1. drug adverse effects 2. narrow spectrum of drug activity 3. poor tissue penetration 4. drug resistance

Question 36

_____ is a polyene anti fungal which acts by creating pores in fungal ergosterol walls. It is the only FDA approved topical and is pregnancy category c. Polyenes have negligible resistance

Answer 36

Natamycin

Question 37

____ act by inhibiting ergosterol synthesis. They inhibit some cytochrome P450 enzymes which reduces metabolism of other drugs. They can develop resistance.

Answer 37

Azoles

Question 38

______ refers to branching out and expanding infection

Answer 38

Fungistatic

Question 39

______ inhibit glucan synthesis which weakens cell wall. It has poor oral availability which renders them to be used in hospital settings.

Answer 39

Echinocandins

Question 40

What are anti fungal adverse reactions of amphotericin B

Answer 40

renal toxicity

Question 41

What are anti fungal adverse reactions of flucytosine

Answer 41

bone marrow toxicity, hepatotoxicity

Question 42

What are anti fungal adverse reactions of azoles

Answer 42

Ketoconazole: supplanted by other members of this group due to pronounced hepatotoxicity Fluconazole: hepatoxicity and GI disturbances

Question 43

What are anti fungal adverse reactions of echinocandins

Answer 43

notable less risk of hepatotoxicity since they are not metabolized by major liver enzymes.

Question 44

what is the most common toxicity associated with anti fungal agents

Answer 44

hepatoxicity

Question 45

what is responsible for the most virulent form of infectious keratitis having the worst prognosis

Answer 45

acanthamoeba; mostly associated with contact lens wear. can go into dormant phase. Found in fresh water, soil, and airborne cysts

Question 46

Although medical therapy for acanthameoba is not well established, corneal epithelial debridement and topical ______ are options

Answer 46

biguanides

Question 47

What do the macrolides consist of

Answer 47

1. Azythromycin 2. Erythromycin 3. Clarithromycin

Question 48

What are macrolide adverse reactions?

Answer 48

1. Augment plasma levels of theophylline | 2. Breast cancer

Question 49

What are contraindications of macrolides

Answer 49

Pregnancy! Avoid Clarithromycin (Preg Category C)

Question 50

What is highly toxic orally thus now limited to topical use only

Answer 50

chloramphenicol; stand alone drug

Question 51

What results in grey baby syndrome and optic neuritis with prolonged therapy

Answer 51

chloramphenicol

Question 52

Bacteria utilize ____ for folate synthesis. Sulfonamides act as competitive agonists

Answer 52

PABA