Antivirals/Antifungals/Anti-parasites Flashcards
Which medication, when administered intravenously, would be the treatment of choice for herpes simplex encephalitis?
A. Cidofovir
B. Foscarnet
C. Valacyclovir
D. Acyclovir
D. Acyclovir.
Intravenous acyclovir is the treatment of choice for herpes simplex encephalitis. Oral agents like valacyclovir should not be used in encephalitis; foscarnet is more likely to have renal side effects; and cidofovir does not cross the blood-brain barrier and cannot treat encephalitis.
What makes cidofovir distinct from acyclovir?
A. Cidofovir is a nucleotide analog and does not need to be converted to function.
B. Cidofovir needs to be triphosphorylated by a viral kinase to function.
C. Cidofovir does not directly inhibit viral DNA polymerase.
D. Cidofovir cannot compete with deoxyguanosine triphosphate for viral DNA polymerase.
A. Cidofovir does not require initial phosphorylation by viral kinases and can be used in acyclovir or ganciclovir-resistant HSV and CMV infections. It is phosphorylated and activated purely by cellular enzymes.
Which medication can be used for daily suppressive therapy for recurring Herpes Simplex Virus (HSV)?
A. Cidofovir
B. Foscarnet
C. Acyclovir
D. Valacyclovir
D. Valacyclovir can be used for daily suppressive therapy for patients with recurrent HSV. It is often preferred because it can be dosed once per day and has superior bioavailability.
Which of the following is a significant and important adverse reaction to acyclovir?
A. Pulmonary fibrosis
B. Acute kidney injury
C. Drug-induced liver injury
D. Tachyarrhythmia
B. AKI.
IV acyclovir can cause renal impairment. Specifically, it can lead to interstitial nephritis or crystalline nephropathy, although these side effects are uncommon with adequate hydration and slower infusion rate.
Which of the following best describes the conversion process of acyclovir to acyclovir triphosphate?
A. Acyclovir is converted directly to acyclovir triphosphate via cellular enzymes.
B. Acyclovir is spontaneously converted to acyclovir triphosphate in the presence of ATP.
C. Acyclovir is first converted into acyclovir monophosphate via virus-encoded thymidine kinase, then cellular enzymes perform the subsequent phosphorylation steps.
D. Acyclovir is first converted into acyclovir monophosphate via cellular enzymes, then virus-encoded thymidine kinase performs the additional phosphorylation steps.
C.
Acyclovir is a guanosine nucleoside analog that needs to be converted before it can be fitted into viral DNA. It is first converted into acyclovir monophosphate via virus-encoded thymidine kinase, a process that occurs selectively in virus-infected cells. Cellular enzymes handle the subsequent phosphorylation steps.
In an overproduction of adrenal cortisol, as seen in Cushing’s disease, which azole is utilized to reduce cortisol levels?
A. Itraconazole
B. Fluconazole
C. Voriconazole
D. Ketoconazole
D. Ketoconazole is used in cases where there is an excess of adrenal cortisol as seen in Cushing’s disease. The medication inhibits cortisol biosynthesis, thus helping to manage the overproduction.
Which azole agent has excellent central nervous system penetration and is used as lifelong maintenance therapy for cryptococcal meningitis?
A. Itraconazole
B. Ketoconazole
C. Clotrimazole
D. Fluconazole
D. Fluconazole has excellent penetration of the central nervous system. This attribute makes it ideal for treating cryptococcal meningitis in patients with AIDS as well as for lifelong maintenance therapy.
What is the primary target and mechanism of action of azole antifungal drugs?
A. They target the cell wall of fungi, by blocking glucan synthesis.
B. They target the cell membrane of fungi, by inhibiting ergosterol synthesis.
C. They target fungal DNA synthesis, by inhibiting DNA gyrase.
D. They target protein synthesis in fungi, by inhibiting the 30S ribosomal subunit.
B. Azole antifungal drugs target the cell membrane of the fungi. They specifically inhibit the synthesis of ergosterol (a component of the fungal cell membrane), leading to increased membrane permeability and cell death.
Which of the following azole drugs is most associated with visual disturbances as a side effect?
A. Fluconazole
B. Itraconazole
C. Ketoconazole
D. Voriconazole
D. Voriconazole is a clinically relevant antifungal drug that has unique side effects, including visual disturbances such as blurred vision or flashes of light. Such occurrences are typically transient.
A college student being treated with metronidazole for vaginitis drinks a beer at a frat party. Which of the following adverse effects are they most likely to experience?
A. Liver injury
B. Hallucinations and seizures
C. Syncope
D. Facial flushing and vomiting
D. Ingesting alcohol while receiving metronidazole therapy can trigger a disulfiram-like reaction, characterized by flushing, palpitations, nausea, and vomiting.
Metronidazole can be substituted for which antibiotic in the treatment of Helicobacter pylori infection in penicillin-allergic patients?
A. Clarithromycin
B. Ciprofloxacin
C. Amoxicillin
D. Azithromycin
C. Amoxicillin. In the treatment of Helicobacter pylori infection, metronidazole can be substituted for amoxicillin in patients allergic to penicillin.
What is metronidazole’s mechanism of action?
A. Disrupts bacterial cell wall synthesis
B. Inhibits bacterial protein synthesis
C. Disrupts bacterial DNA
D. Inhibits bacterial RNA synthesis
C. Metronidazole forms toxic free radical metabolites in the cell that disrupt bacterial DNA. This leads to bacterial cell death (metronidazole is bactericidal).
Metronidazole can not be used to treat infections caused by which of the following organisms?
A. Anaerobic bacteria
B. Aerobic bacteria
C. Protozoa
D. All of the above
B. Aerobic. Metronidazole is effective against anaerobic bacteria and certain protozoan infections, including Giardia. However, it is not effective against aerobes.
The APN understands that the patient prescribed ethambutol must be followed up with by specialists in which department?
correct
1. Ophthalmology
2. Cardiology
3. Gynecology
4. Urology
- Ophthalmology. Ethambutol is an effective drug, but its main limitation is ocular toxicity, which causes optic neuritis leading to blurred vision, color blindness, and visual field constriction.
When does the World Health Organization (WHO) endorse starting antiretroviral therapy (ART) in a newly diagnosed patient with HIV?
correct
1. Within 7 days to the same day of newly diagnosed HIV patient
2. Within 20 days of newly diagnosed HIV patient
3. After the viral load numbers
4. Within 6 months of newly diagnosed HIV patient
- 7 days to same day
