Test Two: Antifungals

Question 0

Why does amphoterecin B need to be prepared carefully?

Answer 0

Highly polar-cannot be taken orally, and easily photo-oxidized

Question 1

Basic mechanism of action for antifungals

Answer 1

Disruption of cell membrane
Denature proteins
Interfere with metabolic processes

Question 2

Mechanism of action for amphoterecin B?

Answer 2

Fungistatic/cidal depending on dose. Binds to ergosterol to alter cell membrane permeability

Question 3

How is nystatin/mycostatin diff from amphoterecin b?

Answer 3

Same method of action on ergosterol, but narrower spectrum and does not absorb into skin so it acts locally

Question 4

Nystatin dosage forms

Answer 4

Lozenges, suspensions for oral thrush, and topical creams in conjunction with steroids like triamcinolone for anti-inflammatory properties

Question 5

What is the action of griseofulvin?

Answer 5

Fungistatic–affects fungal replication, absorbed well with fatty meals bc of increased bile secretion, can reach hair, skin, and nails

Question 6

Important facts about azoles

Answer 6

Used for systemic mycoses
Inhibit ergosterol synthesis by blocking an enzyme
Can interfere with steroid hormone formation–don’t take during puberty (esp ketoconazole)

Question 7

Why shouldn’t ketoconazole be taken with antacids?

Answer 7

They are absorbed readily in acidic environments

Question 8

How is fluconazole/diflucan diff from ketoconazole?

Answer 8

Well absorbed from GIT with less sensitivity to high pH, less potent inhibitor of steroid hormones, good for systemic use like yeast infxn-only one dose necessary

Question 9

What is the use of clotrimazole?

Answer 9

Good for topical use (ringworm or athletes foot) , can cause GI upset, available for intraoral use as 10 mg troche

Question 10

What is used to treat influenza?

Answer 10

Amantadine inhibits viral replication

Osteltamivir (tamiflu) inhibits neuraminidase, should be taken within first days of being infected (like a prophy)

Question 11

Acyclovir use

Answer 11

Effective against HSV, VZ, CMV (esp immune compromised) as a nucleoside analog–inhibits DNA polymerase and viral synthesis

Question 12

Acyclovir side effects

Answer 12

Not very prominent bc not taken for a long time, ointment can cause pain/pruritis and tablet can cause nephrotoxicity

Question 13

Valcyclocir/valtrex

Answer 13

Prodrug of acyclovir, similar to acyclovir except rapid oral absorption and tx acyclovir-resistant HSV (same as Foscarnet-causes electrolyte imbalance) 500-1000mg daily

Question 14

Nucleoside reverse transcriptase inhibitors (NRTIs)

Answer 14

NRTIs are faulty versions of building blocks that HIV needs to make copies of itself. Ie: zidovudine (AZT)

Question 15

Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)

Answer 15

NNRTIs disable a protein needed by HIV to
make copies of itself as they attach themselves
to reverse transcriptase and prevent the enzyme
from converting RNA to DNA.

Question 16

Protease inhibitors for HIV

Answer 16

Disable protease which is needed for hiv to make copies of itself

Question 17

Integrate inhibitors

Answer 17

Raltegravir (Isentress) works by disabling integrase, a protein that HIV uses to insert its genetic material into CD4 cells

Question 18

Halogens

Answer 18

Broad spectrum, reacts with enzymes

Question 19

Chlorine

Answer 19

Sodium hypochlorite inhibited by organic debris

Question 20

Iodine

Answer 20

Non-toxic, non-corrosive, not inhibited by organic

debris, broad spectrum, but causes staining

Question 21

Glutaraldehyde

Answer 21

Not limited by organic debris, broad spectrum, not good for surface disinfection

Question 22

Phenols

Answer 22

Broad spectrum, active against organic material, examples are Eugenol and triclosan (used in toothpaste)