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30 Cards in this Set

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Nystatin (Mycostatin)
Class: Polyene
MOA: Stops ergosterol synthesis. Ergosterol is part of the fungal cell membrane. Forms a pore in the membrane so contents leak out and cell bursts.
Indication: Drug of choice for fungal infections of the oral cavity
Broad spectrum of activity-
Candida, Histoplasmosis, Cryptococcus
Used prophylactically in immunocompromised patients
Not absorbed from skin or mucosal membranes (GI Tract)
Too toxic for parenteral use, only used topically
Drug of choice for pts with liver disease or alcoholism
For extensive disease: Ketoconazole or fluconazole with Nystatin
Dosage forms:
Oral Suspension 100,000 u/mL
-5mL S and S 5x/day
Lozenges 200,000 units
-Dissolve completely in mouth (do not chew or swallow whole) 5x/day
NPO ½ hour after use
-Both treatments usually last 14 days
-Patients say it has a bitter, foul taste
Clotrimazole (Mycelex)
Class: Imidazole
MOA: Stops ergosterol synthesis. Ergosterol is part of the fungal cell membrane
Binds to the oral mucosa, gradually released, fungistatic concentrations for several hours
Indication: Candidiasis, fungal infections
Dosage: Troches 10 mg
Dissolve completely in mouth (do not chew or swallow whole) 5 times per day
NPO ½ hour after use
Only used topically because not absorbed from the GI tract
^Binds to the oral mucosa, gradually released, fungistatic concentrations for several hours^
Patients report that it tastes better than nystatin
Ketoconazole (Nizoral)
Class: Imidazole
MOA: Stops ergosterol synthesis. Ergosterol is part of the fungal cell membrane
Binds to the oral mucosa, gradually released, fungistatic concentrations for several hours
Indication: Candidiasis, fungal infections
Dosage:
Can be used topically (cream 2 %) or orally (tablets 200 mg)
Well absorbed from the GI tract in conditions of low pH
Drug interaction with drugs that increase the pH of the stomach
Dose: 1 tab qd with orange juice or a meal for 14 days
Adverse Effects: hepatoxicity (0.01 %)
Inhibits synthesis of testosterone and estradiol
Inhibitor of Cytochrome p450 3A4
-Cyclosporin
-Phenytoin
-Sulfonylureas
-Warfarin
Fluconazole (Diflucan)
Class: Triazole
MOA: A triazole derivative: more selective inhibitor of fungal cell membrane p450
Adverse Effects: GI upset, less hepatoxicity than ketoconazole
Weak inhibitor of p450 3A4: fewer drug interactions
Uses: Candidemia, osteomyelitis, meningitis
-Therapy for 3-6 months
-Life long in HIV patients
-Prophylaxis in bone marrow transplant
Dosage:
Tablets 100 mg
-2 tabs stat, then 1 qd for 13 days
Suspension 50 mg/5 mL
-Rinse mouth with 20 mL on day 1 for 1 minute then swallow Repeat with 10 mL qd for 14 days total
IV form:
Uses: Candidemia, osteomyelitis, meningitis
-Therapy for 3-6 months
-Life long in HIV patients
-Prophylaxis in bond marrow transplant
Resistance
Decreased susceptibility
-correlate with treatment failure in HIV positive patients
Fluconazole resistant fungi are cross resistant to other azole antifungal agents
Itraconazole (Sporanox)
Class: Triazole
MOA: Significant inhibitor of p450 3A4
If infection is resistant to nystatin, ketoconazole, fluconazole
Resistance in Candida species isolated from patients on prolonged therapy
Dosage:
Capsules 100 mg and suspension 10 mg/mL
Take 1 capsule bid
Rinse mouth with 20 mL for 1 minute qd then swallow and continue for 14 days
Iodoquinol
Class: hydroxyquinoline
Halogenated hydroxyquinoline with amebicidal, antitrichomonal, antibacterial and antifungal activity
MOA: Chelates trace metals at bacterial surfaces that are essential for growth
Indications: angular cheilitis
Dosage forms: 1 % topical cream with 1 % hydrocortisone
Apply to affected areas after each meal and hs
Oral Candidiasis in immunocompetent patients
1. Clotrimazole Lozenges 10 mg
2. Nystatin Lozenges 200,000 units
-Dissolve slowly in mouth (do not chew or swallow whole) 5 times per day
-NPO ½ hour after use
3. Fluconazole tablets 150 mg
-Take one tablet po stat
Oral Candidiasis in immunocompromised patients or mucocutaneous candidiasis
1. Fluconazole Oral Suspension 50 mg/5 mL
2. Itraconazole Oral Suspension 10 mg/ mL
-Rinse mouth with 20 mL for 1 minute then swallow qd and continue for 14 days
3. Fluconazole tablets 100 mg
-Take 2 tablets stat, then 1 tablet qd for 13 days
Chronic atrophic candidiasis associated with a denture
1. Nystatin Cream 100,000 u/g
2. Clotrimazole Cream 1 %
3. Ketoconazole Cream 2 %
-Apply thin coat of medicine to entire inner surface of denture after each meal for 14 days
Full strength bleach: only for dentures without metal
-Soak for 10 minutes once a week then rinse well
Anti-fungal Vaginal tablets
-Dissolve tablet in water, soak denture for 10 minutes
Amphotericin
Class: Polyene
Mechanism is identical to Nystatin
Binds to cholesterol in plasma membranes
Most toxic antibiotic in current use: given over a period of 2-6 hours
Adverse Effects: Hypotension, delirium, fever, nausea, vomiting, abdominal pain, anorexia, headache, nephrotoxicity
AKA “amphoterrible”
Premedicate with Benadryl, Tylenol, and dexamethasone
Caspofungin
Class: Echinocandin
Inhibition of glucan synthase
Enzyme is present in fungal cells not mammalian cells
Inhibition synthesis of 1,3-β-D-glucan
-Essential component of fungal cell walls
Candidemia, invasive aspergillus, candida abscesses, deep tissue infections, refractory or invasive infections
Anidulafungin
Class: Echinocandin
Inhibition of glucan synthase
Enzyme is present in fungal cells not mammalian cells
Inhibition synthesis of 1,3-β-D-glucan
-Essential component of fungal cell walls
Candidemia, invasive aspergillus, candida abscesses, deep tissue infections, refractory or invasive infections
Micafungin
Class: Echinocandin
Inhibition of glucan synthase
Enzyme is present in fungal cells not mammalian cells
Inhibition synthesis of 1,3-β-D-glucan
-Essential component of fungal cell walls
Candidemia, invasive aspergillus, candida abscesses, deep tissue infections, refractory or invasive infections
Flucytosine
Class: antimetabolite
Po only
Metabolized to 5-FU, cancer drug
Then to 5-F-dump: inhibits DNA synthesis
Then to 5-FUTP: inhibits RNA synthesis
Cryptococcal endocarditis or meningoencephalitis
Posaconazole
Class: triazole
Your future
Once itraconazole is resistant
Same mechanism of other triazole anti-fungals
Candida prophylaxis in immunocompromised patients
Treatment of refractory or invasive fungal infections
Voriconazole
Class: triazole
Your future
Once itraconazole is resistant
Same mechanism of other triazole anti-fungals
Candida prophylaxis in immunocompromised patients
Treatment of refractory or invasive fungal infections
Acyclovir
Class: Polymerase inhibitor
MOA: Guanosine analog (2 carbon atoms missing from ribose, no –OH for polymerase rxn)
Selective phosphorylation:
Basis for selectivity of drug for virus infected cells
3000 fold greater concentration required to inhibit non-infected cell growth
Dosage:
Ointment:
-Symptomatic relief of recurrent herpes labialis
Oral
Prophylaxis and treatment primary and recurrent of genital herpes
Preventing reactivation in immunosuppressed patients
Bioavailability: 20 % dose is 200 mg 5 x’s/day
Drug resistance:
Loss of viral thymidine kinase activity
Elaboration of a viral thymidine kinase with altered substrate specificity
Expression of altered DNA polymerase activity
Valacyclovir
Class: Polymerase inhibitor
Greater bioavailability than Acyclovir
MOA: Guanosine analog (2 carbon atoms missing from ribose, no –OH for polymerase rxn)
Selective phosphorylation:
Basis for selectivity of drug for virus infected cells
3000 fold greater concentration required to inhibit non-infected cell growth
Indications: Herpetic gingivostomatitis
Recurrent intraoral herpes simplex
Herpes labialis
Herpes zoster
Dosage:
Ointment:
-Symptomatic relief of recurrent herpes labialis
Oral
Prophylaxis and treatment primary and recurrent of genital herpes
Preventing reactivation in immunosuppressed patients
Bioavailability: 54 % dose is 2G q12h
*Ganciclovir (Cytovene)
Same mechanism as acyclovir
Same specificity for viral thymidine kinase
Inhibits viral DNA polymerase
More potent than acyclovir against HSV, CMV and VZV
Used for acyclovir resistant HSV infections
Adverse effects: aspermatogenesis, carcinogenic and teratogenic
Ganciclovir: always iv
Valganciclovir: oral form
900 mg once daily with food
Penciclovir (Denavir)
Class: Polymerase inhibitor
MOA: Inhibits HSV polymerase competitively with deoxyguanosine triphosphate
Indicated for HSV-1 and HSV-2
Off-label varicella-zoster
Dose- Apply every 2 hours while awake for 4 days. Treatment should be started as early as possible (during prodrome phase)
½ day shorter duration of disease
Valganciclovir
Class: Polymerase inhibitor
Same mechanism as acyclovir
Same specificity for viral thymidine kinase
Inhibits viral DNA polymerase
More potent than acyclovir against HSV, CMV and VZV
Used for acyclovir resistant HSV infections
Adverse effects: aspermatogenesis, carcinogenic and teratogenic
Ganciclovir(Cytovene): always iv
Valganciclovir: oral form
900 mg once daily with food
Abreva
Class: Fusion inhibitor
Over the counter so you can recommend
MOA: inhibits fusion between the human cell membrane and HSV—
Prohibits entry into human cell
Directions for use: apply 5 x’s/day starting at the early stage (redness) to stop progressing to the blister stage
One day shorter
Use a maximum of 10 days
Enfuvirtide (Fuzeon)
Class: entry inhibitor
MOA: Gp41 initiates fusion of the virus into the lymphocyte cell surface
Binds to the first heptad repeat in the gp41 subunit of the viral glycoprotein
Prevents conformational changes
Evidence of HIV-1 replication despite ongoing antiretroviral therapy
Resistance: Substitutions in the aa’s in the gp41 protein
Indication: HIV
Maraviroc (Selzentry)
Class: entry inhibitor
MOA: Selectively and reversibly binds to the CCR5 coreceptor located on human CD4 cells
Prevents interaction between the human CCR5 coreceptor and the gp120 subunit of the viral envelope glycoprotein
Inhibits gp120 conformational change required for CCR5 HIV-1 fusion with the CD4 cell and subsequent cell entry
Indication: HIV
Amantadine (Symmetrel)
Class: Ion channel blockers
Prevents the release of infectious viral nucleic acid into the host cell
Interferes with the influx of protons through a transmembrane domain of the viral M2 protein
Indication: influenza
Reduces infection rates by 50 % and illness rates by 60 %
CNS depression
Oseltamivir (Tamiflu)
Class: Neuro amidase inhibitor
Neuraminidase
-present on the surface of influenza virus particles
-enables the virus to separate itself from cells
Uses:
-uncomplicated acute illness due to influenza A and B virus
-adults and pediatric patients 1 year of age and older
-symptomatic for no more than 2 days
-Prophylaxis
Not Recommended
-Underlying airway disease (asthma or COPD)
Zidovudine
Class: NRTI (polymerase inhibitor)
MOA: Inhibit the reverse transcriptase enzyme by mimicking naturally occurring nucleotides
Have to be phosphorylated to be active
Incorporated into viral complementary DNA
Terminates chain elongation
HIV reverse transcriptase
100 times more susceptible to inhibition than mammalian DNA polymerase
Significantly reduces the incidence of neonatal infection from 30 % to 1 %
Indication: HIV
Efavirenz (Sustiva)
Class: NNRTI (polymerase inhibitor)
MOA: Inhibit the reverse transcriptase by binding directly to the enzyme adjacent to the active site
Low resistance barrier
5% of treatment naïve patients initially present with resistance
Single mutation confers resistance
Al exhibit cross resistance
Many drug interaction via P450s
False positive cannabinoid test
Indication: HIV
Saquinavir (Invirase)
Class: Protease inhibitor
MOA: Inhibit the HIV protease enzyme
Cuts proteins into usable portions to make new functional virions
Uncut proteins means that the virions leave the cells without the ability to infect other cells
Combination therapy
-Many are given with a low dose of another PI (Ritonavir(strong inhibition of CYP3A4, Used in small doses (100 mg) to “boost” other Pis, Inhibits their metabolism, Other Pis can be given in higher concentrations for longer period of time), or Norvir)
Indication: HIV
Interactions:
Substrates
-Diazepam (Valium)
-Alprazolam(Xanax)
Triazolam (Halcion) is contraindicated
Inhibitors
-Fluconazole
-Itraconazole
-Ketoconazole
Raltegravir (Isentress)
Class: integrase inhibitor
Integrase:
Creates available ends on viral DNA
Splices viral DNA into the host DNA inside the nucleus
Indication: HIV