Anti Infectives part 2 Flashcards
Sulfanomides compete with _____
PABA
Sulftanomides are combined with _____ in a 5:1 ratio.
Trimethoprim
What is involved in the inhibition of dihydropteroate synthase
PABA doesn’t convert to DHF
What is involved in the inhibition of dihydrofolate reductase
DHF doesn’t covert to THF
Polytrim solution (polymyxin B + trimethoprim) as well as sulfadiazine and ______ are drugs used together to treat taxoplasmosis and are folic acid inhibitor combos
pyrimethamine
____ is first line treatment for MRSA with 95% efficacy
Trimethoprim
What are folic acid inhibitor adverse reactions
- Hypersensitivity
2. Blood dycrasias
What are folic acid inhibitor adverse reactions for sulfonamides
- Stevens Johnson syndrome
- Nephrotoxicity
- Coumadin potentiation
- Myopia +/- astigmatism (reverible)
* Contraindicated in pregnancy!
What are folic acid inhibitor adverse reactions for trimethoprim
bone marrow suppression
*contraindicated in pregnancy!
______ are DNA synthesis inhibitors
Fluoroquinolones
Fluoroquinolone’s are bactericidal and inhibit DNA gyrase and _____
topoisomerase IV
____ is the only fluoroquinolone that is a topical suspension and is a 5th generation flouroquinolone
Besifloxacin
____ and ____ are 2nd generation fluoroquinolones.
Ciprofloxacin and ofloxacin
____ is a 3rd generation fluoroquinolone
Levofloxacin
_____ and ___ are fourth generation fluoroquinolones
moxifloxacin and gatifloxacin
What are fluoriquinolone adverse reactions
- phototoxicity
- tendinitis
- reduced levels in combinations w antacids, Fe, and Zn
- convulsions (pO)
- ciprofloxacin –> white corneal precipitates, reduced metabolism of theophylline
what are contraindications of fluoroquinolone
- less than 18 yoa (pO) due to inhibition of bone growth and damage to cartilage.
- pregnancy
The best topicals for treating psudomanas infections are fluoroquinolones, aminoglycosides and ______
polymyxin B
What are the best ocular ab’s for children
- trimethorpim/polymyxin B
2. AzaSite
What are the best ocular Ab’s for adults
- Mild: Bacitracin/polymyxin B
- Moderate: Neomycin
- Tobramycin
- Severe: Besifloxacin or Levofloxacin
The dilemma to combine an antimicrobial agent and steroid depends on all of the following:
- oval shaped processes at/near the limbus are inflammatory
- severity of infection relative to conjunctival injection
- Is the corneal epithelium intact?
- Does pt test positive for lymphadenopathy
When choosing Antibiotics select drugs with the _____ spectrum and use ____ agents whenever possible so we don’t make them susceptible to resistance
narrowest; older
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
host; mutation
_____ 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.
adenovirus
If patient comes in your office and they have AIDs ask about:
- viral load
2. T cell count
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 ______
Trifluridine; C
What are the purine analogs that are used
- Acyclovir (Preg category B)
- Ganciclovir (Preg category C
- Famciclovir
- Valcyclovir
Both acyclovir and ganciclovir have oral risk of ____ ____
blood dycrasias
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 _______
half; Acyclovir
_____ is drug of choice for HS keratitis therapy due to lower dosing frequency
Famciclovir
What is the ocular involvement with fungal infections
- cornea
- conjunctiva
- lens
- ciliary body
- vitreous body
- uvea
Which yeasts are involved ocularly
- Candida
2. Cryptococcus
Which molds are involved ocularly
- aspergillus
- fusarium
- curvularia
What causes enhanced risk of fungal infection
- contact lens wear
- steroids
- trauma
- immunocompromise
What are therapeutic concerns of fungal infections
- drug adverse effects
- narrow spectrum of drug activity
- poor tissue penetration
- drug resistance
_____ 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
Natamycin
____ act by inhibiting ergosterol synthesis. They inhibit some cytochrome P450 enzymes which reduces metabolism of other drugs. They can develop resistance.
Azoles
______ refers to branching out and expanding infection
Fungistatic
______ inhibit glucan synthesis which weakens cell wall. It has poor oral availability which renders them to be used in hospital settings.
Echinocandins
What are anti fungal adverse reactions of amphotericin B
renal toxicity
What are anti fungal adverse reactions of flucytosine
bone marrow toxicity, hepatotoxicity
What are anti fungal adverse reactions of azoles
Ketoconazole: supplanted by other members of this group due to pronounced hepatotoxicity
Fluconazole: hepatoxicity and GI disturbances
What are anti fungal adverse reactions of echinocandins
notable less risk of hepatotoxicity since they are not metabolized by major liver enzymes.
what is the most common toxicity associated with anti fungal agents
hepatoxicity
what is responsible for the most virulent form of infectious keratitis having the worst prognosis
acanthamoeba; mostly associated with contact lens wear. can go into dormant phase. Found in fresh water, soil, and airborne cysts
Although medical therapy for acanthameoba is not well established, corneal epithelial debridement and topical ______ are options
biguanides
What do the macrolides consist of
- Azythromycin
- Erythromycin
- Clarithromycin
What are macrolide adverse reactions?
- Augment plasma levels of theophylline
2. Breast cancer
What are contraindications of macrolides
Pregnancy! Avoid Clarithromycin (Preg Category C)
What is highly toxic orally thus now limited to topical use only
chloramphenicol; stand alone drug
What results in grey baby syndrome and optic neuritis with prolonged therapy
chloramphenicol
Bacteria utilize ____ for folate synthesis. Sulfonamides act as competitive agonists
PABA
