Medical Pharmacology: Antiviral Drug Practice Questions
Click on the correct answer.
Didanosine (Videx):
Classified as a dideoxynucleoside inosine analog.
Didanosine is a prodrug requiring activation to the triphosphate form.
Both
Neither
Didanosine (Videx):
The triphosphate, active form of didanosine inhibits viral reverse transcriptase by competitive inhibition.
The danosine triphosphate is incorporated into viral DNA taking the place of deoxyladenosine triphosphate resulting in chain termination.
Both
Neither
Didanosine (Videx) pharmacokinetics:
Oral availability is nearly 100%
In order to prevent drug-inactivation by stomach acid, enteric-formulations may be used.
Both
Neither
Didanosine pharmacokinetics
CSF drug levels are about 1/5 of that found in the serum.
Serum half-life is only about 1.5 hours; however, intracellular half-life of the triphosphate (activated) metabolite is about a day.
Both
Neither
Didanosine (Videx) a.k.a. DDI, together with other antiretrovirals, may be used in the treatment of HIV-1.
True
False
FDA warnings with respect to adverse effects following didanosine administration includes/includes:
Pancreatitis
Lactic acidosis
Hepatomegaly with stenosis
A & B
B & C
A & C
A, B & C
"Lactic acidosis in severe hepatomegaly with stenosis, including fatal cases, have been reported with the use of nucleoside analogs alone or in combination, including didanosine and other antiretrovirals."
RxList
True
False
Enteric-coated formulations of didanosine should not be coadministered with stavudine because the combination predisposes to serious, potentially life-threatening toxicities.
True
False
Major clinical toxicities that may follow didanosine administration include/includes:
A peripheral distal sensory neuropathy
(incidence is about 15%-20% of didanosine-treated patients)
Dose-dependent pancreatitis
Both
Neither
Significant pancreatitis, the principal dose-limiting toxicity with didanosine exhibits an incident of about 3% to 17%. Furthermore, increased incidence is more likely at the higher dose levels and in elderly patients.
In general, didanosine (ddI) is infrequently used since other NRTIs
are available that exhibit reduced toxcities.
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Source Material:
Acosta EP Chapter 62 Antiviral Agents (Nonretroviral)
in Goodman & Gilman's: The Pharmcological
Basis of Therapeutics, 14e, (Brunton LL Knollmann BC eds) McGraw-Hill Education, 2023.
Safrin S Chapter 49 Antiviral Agents in
Basic & Clinical Pharmacology (Katzung BG, Editor;
Vanderah TW, Associate editor) 15e McGraw Hill 2021.
Li JZ Coen DM Chapter 38 Pharmacology of
Viral Infections in Principles of Pharmacology:
The Pathophysiologic Basis of Drug Therapy 4e (Golan DE
Armstong EJ Armstrong AW, eds) Wolters Kluwer 2017.
Waller DB Sampson AP Section 11
Chemotherapy in Medical Pharmacology & Therapeutics
Elsevier 2018.
Burchum JR Rosenthal LD Chapter 97
Antiviral Agents I: Drugs for Non-HIV Viral Infections
in Lehne's Pharmacology for Nursing Care Elsevier 2022.
Waller DB Sampson AP Section 11: Chapter
51
Chemotherapy of infections in Medical Pharmacology & Therapeutics
Elsevier 2018.
Benavides S Bahal O'Mara N Nahata MC
Chapter 79 Viral Infections in Applied Therapeutics:
The Clinical Use of Drugs (Zeind C, Carvalho MG Cheng JW
Zaiken K Lapointe T, eds) Wolters Kluwer, 2024.
Davanathan AS Symonds AE Adams JL
Cottrell ML Chapter 76 Pharmacotherapy of Human
Immunodeficiency Virus Infection
in Applied
Therapeutics: The Clinical Use of Drugs (Zeind C, Carvalho MG Cheng JW
Zaiken K Lapointe T, eds) Wolters Kluwer, 2024.
Flexner CW Chapter 64 Antiretroviral
Agents and Treatment of HIV Infection
in Goodman &
Gilman's: The Pharmcological
Basis of Therapeutics, 14e, (Brunton LL Knollmann BC eds) McGraw-Hill Education, 2023.
Burchum JR Rosenthal LD Chapter
98
Antiviral Agents II: Drugs for HIV Infection and Related
Opportunistic Infections
in Lehne's Pharmacology for Nursing Care Elsevier 2022.
Woster PM Chapter 30 Drugs Used to Treat
Viral Infections in Foye's Principles of Medicinal
Chemistry 8e (Roche VF Zito SW Lemke TL Williams DA, eds)
Wolters Kluwer 2020.
