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NAPLEX 2024 > Chapter 24: ID III Antifungal + Antiviral > Flashcards

Chapter 24: ID III Antifungal + Antiviral Flashcards

1
Q

Fungal Classifications

A
  1. Yeast: Candida Species (c.ablicans, c.topicalis, C.krusei, etc) and Cryptococcus neoformas
  2. Molds: Aspergillus species, Zygomycetes
  3. Dimorphic fungi: Histoplasma capsulatum, Blastomyces dermatitidis, Coccidioides immitis (dimorphics exist as mold in the cold and yeast form in the heat!)
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2
Q

Amphotericin B: MOA, what does it cover, general

A

Binds to ergosterol, altering cell membrane permeability = cell death. It’s a broad spectrum drug and can be used as inital tx for many invasive infection.
- Yeast: most candida species and cryptococcus neoformans
- Mold: Aspergillus species and zygomycetes
- Dimorphics
.
AmpB Deoxycholate (conventional formulation) has MANY toxicities! the lipid formulations are associated with few toxicities (eg. decreased infusion rxn, decreased nephrotox)

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3
Q

What is the different type of Amphotericin B formualtion and dose

A
  1. AmpB Deoxycholate (conventional formulation) injection: 0.1-1.5mg/kg/day
  2. Liposomal AmpB (AmBisome) (lipid formulation) injection: 3-6 mg/kg/day
    .
    Both formulations are yellow/orange in color
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4
Q

Amphotericin B: Boxed warning, SEs, general notes

A
  • Boxed warning: Med errors confusing the lipid based froms (AmBisome and Abelcet) with the conventional form (deoxycholate) has resulted in cardiopulmonary arrest/ death….Conventional AmpB should not exceed 1.5mg/kg/day!
  • SEs: infusion related (fever, chills, HA, malaise, rigors), decreased K+/Mg+, nephrotox
  • Notes: compatible with D5W only, lipid formulas must be filtered
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5
Q

Amphotericin B Deoxycholate (conventional) requires premedications! What are they?

A

Premed help decrease infusion related rxn, give 30-60 mins prior to infusion.
- APAP or NSAID
- Diphenhydramine and/or hydrocortisones
- NS bolus to decrease nephrotox

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6
Q

Flucytosine: MOA

A

penetrates fungal cell and is converted to fluorouracil, which competes with uracil and interferes with fungal RNA/ protein syn. SHOULD NOT be used alone d/t development of resistance… rec to be used with AmpB for tx of invasive cryptococcal (ie. meningitis) or Candida infection

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7
Q

Flucytosine: Dosing, boxed warning/ SEs

A
  • Dosing: 50-150 mg/kg/day
  • BW: caution in patient with renal dysfunction
  • SEs: myelosuppresion, hepatox, renal tox
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8
Q

Azole Antifungals: MOA and general drug interactions?

A
  • MOA: Azoles decrease ergosterol syn and cell membrane formation.
  • Use is sometimes limited d/t CYP interaction (mainly CYP3A4). Azoles are CYP3A4 inhibitors!!!
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9
Q

Azole Antifungals: Fluconazole: Brand, dosing, warnings, notes, SEs

A
  • Fluconazole (Diflucan): 50-800mg PO/IV QD ..for vaginal candidiasis - 150mg PO x 1.
  • Warnings: not recommeded for preg, skin disorder can occur
  • limited use against C. glabrata d/t resistant…not affective against C.Krusei d/t resistance!… Fluconazole is the only Azole that requires renal dose adjustment! (all other azoles are hepatically cleared)
  • Penetrates CNS = can treat fungal meningitis
  • SEs: Increase LFT, QT prolong, HA, rash
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10
Q

Azole Antifungals: Itraconazole: Brand, dosing, Boxed warning, warnings, notes, SEs

A
  • Itraconazole (Sporanox): 200mg PO QD or BID (capsule or solution).
  • BW: Worsen HF! Do not use in patient with HF; can cause an increase in certain drug which can increase QT proling/ V. Tachy
  • Warnings: hepatox; use is limited d/t interactions and less data.. it’s mainly use for dimorphic infection
  • SEs: Increase LFT, QT prolong, HA, rash
  • NOTE: tab/capsule need to be taken with food; solution? take on empty stomach
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11
Q

Azole Antifungals: Ketoconazole: Brand, Boxed warning, notes, SEs

A
  • Ketoconazole: many DDI so now it’s typically only used topically –> Nizoral A-D (OTC)
  • Boxed warning: Hepatoxicitiy that needs transplant!!!, QT prolong…d/t really bad SEs and risk it’s only used topically for the most part. Orally is last line.
  • SEs: Increase LFT, QT prolong, HA, rash
  • NOTE: tab/capsule need to be taken with food; solution? take on empty stomach
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12
Q

Azole Antifungals: Voriconazole: Brands, general dosing

A
  • Voriconazole (Vfend PO/IV)
  • IV: 4-6mg/kg IV Q12; PO: 200mg BID
  • NOTE: PO is perf if CrCl is < 50 d/t accumulation of the vehical SBECD in IV formulation.
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13
Q

Azole Antifungals: Voriconazole: Warnings, Notes

A
  • Warnings: Hepatox, visual distrubances, phototoxicity, QT prolongation, increase LFTs, Increase Scr, CNS toxicity
  • Note: can pass CNS so good option for fungal meningitis; take the PO on empty stomach; use caution when driving at night d/t visual changes, avoid direct sunlight
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14
Q

Azole Antifungals: Posaconazole: brand, general dosing, warnings, note

A
  • Posaconazole (Noxafil) : Dosing varies! 100-400 mg/day (tablets); 300mg BID day 1 then 300mg QD (IV)
  • Warning: QT prolongation, Increase LFTs, rash, decrease K+/Mg+
  • NOTE: TAKE PO WITH FOOD!!!!
  • CrCl is < 50 d/t accumulation of the vehical SBECD in IV formulation
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15
Q

Azole DDI Part 1

A
  • All azoles are moderate -strong CYP3A4 inhibitors .
  • Itraconazole and ketoconazole inhibit P-glycoprotein.
  • Fluconazole and voriconazole inhibit CYP2C9 (which can increase warfarin!!!)
  • Azoles can increase concentrations of apixaban and rivaroxaban. Monitor for s/sx of bleeding
  • Caution with other QT-prolonging drugs (e.g.,
    antiarrhythmics, quinolones, macrolides, antidepressants, methadone, tac, etc.)
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16
Q

Azole DDI Part 2

A
  • PPls can decrease absorption of
    posaconazole
  • Absorption of itraconazole and ketoconazole needs acidic gut! (so if using PPIs? drink an acidic drink firstto create acidic enviroment)
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17
Q

Echinocandins: MOA

A
  • Echinocandins inhibit the synthesis of beta (1,3)-D glucan, a vital part of fungal cell walls.
  • Effective against most Candida species, including azole-resistant strains like C. glabrata and C. krusei!
  • Also active against Aspergillus species, but other drugs are preferred for aspergillosi - combo tx is recommended for treating Aspergillus species
  • Generally well-tolerated, with no significant renal or hepatic toxicity.
  • Only available in injectable form.
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18
Q

Echinocandins

List 2 Echinocandins including brand, general dosing

A
  1. Caspofungin (candidas): 50-70mg IV
  2. Micafungin (Mycamine): Candidemia - 100 mg IV; Esopha Cand - 150 mg IV
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19
Q

Echinocandins: warnings, SEs, notes

A
  • Warnings: Histamine mediated symptoms (ie. rash, swelling, flushing, hypotensive)
  • SEs: increase LFT, N/V/D, hyperglycemia
  • Note: all are given once daily; no dose adj needed for renal. Micafungin needs light protection during admin!!
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20
Q

Other Antifungal Agents

Nystain (suspension, tablets): dosing

A
  • dosing: oral candidiasis: suspension 400,000-600,000 U 4x 7-14 days (swish in mouth and retain as long as you can before swallowing)
  • dosing: intestinal infection: tabs 500,000-1,000,000 U Q8hr
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21
Q

Other Antifungal Agents

Terbinafine (oral, topical - Lamisil AT): dosing, warning, SEs

A
  • Dosing: 250 mg/day
  • Warning: Hepatoxicity
  • SEs: HA, increased LFT, rash
22
Q

Other Antifungal Agents

Clotrimazole: doseage form. dosing regimen for Oropharyngeal Candidiasis

A
  • 10 mg troche/lozenge
  • Oropharyngeal Candidiasis: PPX - 10mg TID; Treatment - 10mg 5 times a day x 7-14 days
23
Q

EMPIRIC TREATMENT FOR SELECT FUNGAL PATHOGENS/INFECTIONS

A
24
Q

How do viruses sustain themselves within host cells, and what are the two primary approaches for treating viral infections?

A

Viruses rely on the metabolic processes of host cells for survival, hence they are termed obligate intracellular parasites. Treatments for viral infections operate by either directly hindering viruses through antiviral agents or by enhancing host defenses against viral infections through immunomodulating agents

25
Q

What are the key characteristics and diagnostic methods for influenza, and who are at higher risk for severe illness from the virus?

A

Influenza A and B are the common strains infecting humans. Diagnostic tests, including molecular assays and antigen detection tests are available. Both influenza A and B can cause severe illness, especially in at-risk individuals such as pregnant women, children < 5 years, adults ~ 65 years, immunocompromised patients, and those with comorbid conditions like diabetes, asthma, or cardiovascular disease. Influenza spreads via respiratory droplets and is contagious one day prior to symptom onset and up to 5 - 7 days after. Common symptoms include fever, chills, fatigue, body aches, cough, sore throat, and headaches. The seasonal influenza vaccine, recommended for all patients age > 6 months with no contraindications, is the most effective prevention method.

26
Q

Antivirals for Influenza

General: Neuraminidase inhibitors

A

Neuraminidase inhibitors (oseltamivir, zanamivir, and peramivir) decrease virus levels by blocking the enzyme responsible for releasing new viral particles from infected cells. Effective against both influenza A and B, they shorten symptom duration by approximately one day and lower influenza complications. For maximum effectiveness, they should be initiated within 48 hours of symptom onset.

27
Q

Antivirals for Influenza

General: Endonuclease inhibitors

A

Baloxavir marboxil (Xofluza) it has the advantage of a single dose regimen (one and done!). It should be started within 48 hours of symptom onset!

28
Q

Antiviral Drugs for Influenza

Oseltamivir: Brand, PPX/TX dosing, warnings, SEs

A
  • Oseltamivir (Tamiflu) for +12y/o: capsule/ suspension
  • Treatment: 75mg BID x 5days
  • PPX: 75mg QD x 10 days
  • Warnings: Neuropsych events
  • SEs: HA, N/V
29
Q

Antiviral Drugs for Influenza

Zanamivir: Brand, PPX/TX dosing, warnings

A
  • Zanamivir (relenza diskhaler) for +5-7y/o:
  • Treatment: Two 5mg inhalation BID x5days
  • PPX: Two 5mg inhalation BID x10days
  • Warnings: Neuropsych events, bronchospasm (do not use in COPD/Asthma)
30
Q

Covid-19

Talk about it: COVID-19 - what is it, S/Sx, diagnosis, care?

A

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerges in the late 2019 (AKA Covid19) with wide range of clinical presentation ranging in severity. Like the flu, Covid19 is spread thru droplets thru cough and sneezing. Spreading can be reduced by staying 6 ft away, wearing mask, and many handwashing.
.
S/Sx: fever, chills, SOB, fatigue, myalgia, loss of taste and smell. Vaccine is the way!
.
Diagnosis is typically thru PCR test using nasopharyngeal swab specimen and or rapid antigen test.
.
Symptomatic care (hydration, analgesics, antitussives) is appropraite for everyone.

31
Q

There are hundreds of herpes viruses in existence, but not all are responsible for causing human disease. Clinically significant herpes viruses include:

A

Herpes simplex viruses 1 and 2 (HSV-1, HSV-2), varicella -zoster virus (VZV), cytomegalovirus (CMV),
Epstein-Barr virus (EBV), HHV-6, HHV-7 and Kaposi sarcoma associated herpes virus (HHV-8)

32
Q

What types of infections can both HSV-1 and HSV-2 cause?

A

Both HSV-1 and HSV-2 can cause various infections, including orofacial infection, genital infection, eye infections, encephalitis, esophagitis, and pulmonary infections. HSV-1 is primarily linked with oropharyngeal disease, while HSV-2 is more closely associated with genital disease

33
Q

Antivirals for Herpes Simplex Virus and Varicella Zoster Virus

name the 2 main drugs (brand/generic)

A
  1. Acyclovir (Zovirax) - tablet, cap, buccal tab, suspension, injection, topical
  2. Valacyclovir (prodrug of acyclovir) (Valtrex) - tablet only
34
Q

Antivirals for Herpes Simplex Virus and Varicella Zoster Virus

Acyclovir and Valacyclovir: warnings, SEs, notes

A
  • Warning: caution in patients with renal impairment, the elderly, and people receving nephrotox drugs
  • SEs: malaise, HA, N/V/D, rash, increase LFT, increase risk of SZ
  • Note: Acyclovir dose is based on IBW, including obese patients
35
Q

Herpes Simplex Labialis (Cold Sores):

A
  • Cold sores are highly contagious and often transmitted within families, primarily caused by HSV-1 in children but can be caused by HSV-2 through oral/genital sex.
  • Viral shedding can occur even without symptoms, but transmission is most common during active lesions. Avoid kissing and sharing drinks when lesions are oozing.
  • Cold sores typically reappear in the same location, often at the junction of the upper and lower lip.
  • Triggers for outbreaks include stress, fatigue, skin trauma (e.g., sun exposure, acid peels), and dental work.
  • Prodrome symptoms (symp that appears before the lesions sppear) such as tingling, itching, or soreness precede sore eruption, indicating the optimal time for applying topical or oral medication to reduce blister duration.
  • For frequent recurrences (> 4 times/year), daily chronic suppression therapy may be prescribed.
  • OTC/RX topicals shorten duration by up to one day, while oral antivirals reduce duration by up to two days.
36
Q

Topical Treatment for Herpes Labialis

Topical Treatment for Herpes Lablalis: Names, OTC or RX?, regimens

A
37
Q

Systemic (oral) Treatment for Herpes Labialis

Acyclovir: Regimens for initial, recurrence, and chronic suppression

A
  • initial: 200mg 5x QD or 400mg TID
  • recurrence: 400mg TID x 5-10 days
  • chronic suppression: 400mg BID
38
Q

Systemic (oral) Treatment for Herpes Labialis

Valacyclovir: Regimens for initial, recurrence, and chronic suppression

A
  • initial: 1 gram BID
  • recurrence: 2 grams BID x 1 day
  • chronic suppression: 500mg or 1 gram QD
39
Q

Systemic (oral) Treatment for Herpes Labialis

Famciclovir: Regimens for initial and recurrence

A
  • initial: 250 mg TID or 500 mg BID
  • recurrence: 1.5 grams x 1dose
40
Q

Genital Herpes

A
  • Genital herpes, caused by HSV-2, is a lifelong viral infection.
  • The first episode typically occurs 2 - 14 days after exposure, with up to 50% of patients being asymptomatic.
  • Symptoms may include flu-like symptoms, fever, headache, malaise, myalgia, and pustular or ulcerative lesions on the external genitalia. Lesions start as papules or vesicles, spread rapidly, form clusters, crust, and then re-epithelialize, causing pain. Itching, dysuria, and vaginal or urethral discharge are common.
  • Treatment should start during prodrome or within one day of lesion onset.
  • Acyclovir (Zovirax) requires up to five doses daily, while valacyclovir (Valtrex) offers higher concentrations with less frequent dosing (yay adherence!).
  • Acyclovir-resistant HSV infections are treated with foscarnet (Foscavir) until healing occurs.
41
Q

Oral Treatment of Genital Herpes In Non-HIV Patients… honestly just know what drugs to use, don’t even bother with dosing :)

A
42
Q

Invasive HSV Infections:

A

HSV is a common cause of viral encephalitis in the U.S.. Key symptoms include sudden fever, focal neurologic symptoms, and altered mental status. Treatment involves IV acyclovir, typically 10 mg/kg/dose every 8 hours for 14-21 days for HSV encephalitis. Other invasive infections like esophagitis and pneumonitis, occurring mainly in immunosuppressed individuals, are treated with IV acyclovir, usually 5 mg/kg/dose every 8 hours

43
Q

Varicella Zoster Virus and Herpes Zoste: what is it? background/ general info

A

Most U.S. adults had chickenpox in childhood, caused by the varicella-zoster virus, which can remain dormant in nerves for years. Reactivation, known as shingles or herpes zoster, often happens with age and acute stress. Though it can occur at any age, it’s most common in adults over 60. Shingles presents as a distinctive, often painful, rash typically on one side of the body (unilateral) and can be accompanied by itching or tingling.

44
Q

Varicella Zoster Virus and Herpes Zoster: Pain Relief options + vaccination?

A

Antiviral treatment for shingles should begin promptly upon the first sign or symptom and is most effective within 72 hours of rash onset. Pain relief options include topical medications (ie. lidocain), neuropathic pain agents (such as pregabalin, gabapentin, duloxetine, and tricyclic antidepressants), NSAIDs, or opioids. While most patients recover without long-term issues, around 5-10% develop chronic pain aka postherpetic neuralgia (PHN), which can be severe and debilitating.
.
The Advisory Committee on Immunization Practices (ACIP) recommends the shingle vaccines (Shingrex) in immunocomp adults >50 y/o and adult >19 y/o who are or will be immunocomp

45
Q

Herpes Zoster (Shingles) Treatment

A
46
Q

Cytomegalovirus: what is it? what is the preferred treatment? what treatments are reserved? and what is it reserved for?

A

Cytomegalovirus (CMV) is double stranded DNA virus; a herpes virus (HHV-5) primarily affecting severely immunocompromised individuals, such as those with AIDS or transplant recipients. It commonly leads to retinitis, colitis, or esophagitis. Ganciclovir and valganciclovir are the preferred treatments, while foscarnet and cidofovir are reserved for resistant cases, treatment-limiting toxicities with ganciclovir, or when CMV strains are resistant to valganciclovir.

47
Q

What drug is used for CMV ppx?

A

Secondary prophylaxis, also known as maintenance, is required for some patients. Letermovir (Prevymis), a non-nucleoside CMV inhibitor, is FDA-approved for CMV prophylaxis in patients undergoing a hematopoietic stem cell transplant who screen positive for CMV

48
Q

CMV Treatment

Valganciclovir: brand, dosing

A

Valcyte (tablet/ solution)..it’s the prodrug of ganciclovir: 900mg po BID x 21 days.
.
Solution must be refrigerated

48
Q

CMV treatment

Ganciclovir: brand, dosing

A

Zirgan (injection): 5mg/kg IV BID x14-21 days

49
Q

CMV Treatment

Ganciclovir and Valganciclovir: Boxed warning, SEs, equivulant?

A
  • BW: myelosuppression, carcinogenic and teratogenic
  • SEs: fever, N/V/D, trombocytopenia/ neutropenia/ ect
  • IV ganciclovie 5mg/kg = PO valgancyclovir 900mg
50
Q

Epstein-Barr Virus (EBV): what is it? S/SX, treatment?

A

Epstein-Barr Virus (EBV), part of the herpes virus family, causes infectious mononucleosis or “mono,” a common infection affecting most people at some point. Spread through bodily fluids, especially saliva, it can transmit via kissing, sharing drinks or food, or contact with contaminated objects. Symptoms include fatigue, fever, sore throat, and swollen lymph nodes, typically resolving within 2-4 weeks. No specific drug treatment or vaccine exists for mono.

NAPLEX 2024 (28 decks)

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