Ganciclovir and Zidovudine MCQs With Answer

Introduction: Ganciclovir and Zidovudine MCQs With Answer provide B. Pharm students a focused review of two key antiviral agents used in clinical practice. This concise, keyword-rich guide covers mechanism of action, pharmacokinetics, spectrum of activity, resistance mechanisms, adverse effects, dose adjustment, monitoring parameters, drug interactions and clinical indications such as CMV disease and HIV therapy. Designed to deepen understanding beyond basics, these MCQs emphasize practical points like prodrug conversion (valganciclovir), myelosuppression risk, renal and hepatic handling, and therapeutic monitoring. Clear explanations reinforce learning for exams and clinical pharmaco-therapeutics. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which enzyme is primarily responsible for the initial phosphorylation of ganciclovir in cytomegalovirus-infected cells?

• Cellular thymidine kinase
• Viral UL97 kinase
• Host deoxyguanosine kinase
• Viral DNA polymerase

Correct Answer: Viral UL97 kinase

Q2. Valganciclovir is used clinically because it:

• Has stronger activity than ganciclovir against CMV
• Is an oral prodrug with improved bioavailability
• Directly inhibits viral protease
• Is activated by thymidine kinase

Correct Answer: Is an oral prodrug with improved bioavailability

Q3. The primary dose-limiting toxicity of ganciclovir is:

• Hepatotoxicity
• Nephrotoxicity
• Myelosuppression (neutropenia)
• Peripheral neuropathy

Correct Answer: Myelosuppression (neutropenia)

Q4. Zidovudine’s mechanism of action involves:

• Inhibition of viral protease
• Nucleoside reverse transcriptase inhibition and chain termination
• Integrase strand transfer inhibition
• Blocking CCR5 co-receptor

Correct Answer: Nucleoside reverse transcriptase inhibition and chain termination

Q5. Which laboratory parameter should be monitored frequently during therapy with both ganciclovir and zidovudine due to overlapping toxicity?

• Serum bilirubin
• Complete blood count (CBC)
• Serum amylase
• Fasting glucose

Correct Answer: Complete blood count (CBC)

Q6. Resistance to ganciclovir in CMV commonly arises from mutations in which viral genes?

• UL97 and UL54
• env and gag
• pol and gag
• rt and integrase

Correct Answer: UL97 and UL54

Q7. Which statement about zidovudine pharmacokinetics is correct?

• It is primarily eliminated unchanged in urine
• It undergoes extensive hepatic glucuronidation
• It has negligible penetration into the CSF
• It is activated by viral kinases only

Correct Answer: It undergoes extensive hepatic glucuronidation

Q8. For CMV retinitis in immunocompromised patients, the initial (induction) therapy commonly uses:

• Oral acyclovir
• IV ganciclovir or oral valganciclovir
• Oral zidovudine
• Topical ganciclovir eye drops only

Correct Answer: IV ganciclovir or oral valganciclovir

Q9. A clinically important interaction between ganciclovir and zidovudine is:

• Reduced antiviral activity of both drugs
• Additive myelosuppression (bone marrow toxicity)
• Increased renal clearance of zidovudine
• Enhanced hepatic metabolism of ganciclovir

Correct Answer: Additive myelosuppression (bone marrow toxicity)

Q10. Which adverse effect is most characteristic of long-term zidovudine therapy?

• Ototoxicity
• Lactic acidosis and hepatic steatosis
• Severe hypertension
• Agranulocytosis only

Correct Answer: Lactic acidosis and hepatic steatosis

Q11. The active triphosphate form of zidovudine inhibits HIV replication by:

• Competing with natural nucleotides and causing chain termination
• Directly cleaving viral RNA
• Blocking viral entry into cells
• Inhibiting viral protease

Correct Answer: Competing with natural nucleotides and causing chain termination

Q12. Ganciclovir is primarily eliminated by which route, requiring dose adjustment in organ impairment?

• Hepatic metabolism via CYP3A4
• Renal excretion (glomerular filtration and tubular secretion)
• Biliary excretion unchanged
• Metabolism by gut flora

Correct Answer: Renal excretion (glomerular filtration and tubular secretion)

Q13. Which of the following best explains why valganciclovir has better oral absorption than ganciclovir?

• Valganciclovir is more lipophilic and is a valine ester prodrug
• Valganciclovir binds strongly to plasma proteins
• Valganciclovir inhibits intestinal P-glycoprotein
• Valganciclovir undergoes first-pass metabolism to active form

Correct Answer: Valganciclovir is more lipophilic and is a valine ester prodrug

Q14. A mutation in HIV reverse transcriptase that reduces incorporation of zidovudine triphosphate is called:

• Protease mutation
• Thymidine analogue mutation (TAM)
• Integrase strand transfer mutation
• NS5A resistance mutation

Correct Answer: Thymidine analogue mutation (TAM)

Q15. Which monitoring is essential before and during ganciclovir therapy?

• ECG weekly
• Serial complete blood counts and renal function tests
• Serum amylase monthly
• Fasting lipid profile

Correct Answer: Serial complete blood counts and renal function tests

Q16. Which adverse effect is commonly associated with zidovudine and is an indication for regular monitoring?

• Hyperglycemia
• Macrocytic anemia
• Bronchospasm
• Hypokalemia

Correct Answer: Macrocytic anemia

Q17. Ganciclovir’s mechanism of action is best described as:

• Inhibition of viral protease synthesis
• Inhibition of viral DNA polymerase after phosphorylation
• Inhibition of viral entry receptors
• Non-specific immune stimulation

Correct Answer: Inhibition of viral DNA polymerase after phosphorylation

Q18. In pregnant women with HIV, zidovudine is used primarily to:

• Treat CMV infection during pregnancy
• Reduce mother-to-child transmission of HIV
• Prevent toxoplasmosis transmission
• Increase maternal CD4 counts acutely

Correct Answer: Reduce mother-to-child transmission of HIV

Q19. Which of the following is a reason to avoid co-administration of ganciclovir with strong nephrotoxic drugs?

• Ganciclovir increases hepatic enzymes of nephrotoxic drugs
• Combined nephrotoxicity and risk of increased ganciclovir levels
• They form inactive complexes in plasma
• They reduce ganciclovir oral absorption

Correct Answer: Combined nephrotoxicity and risk of increased ganciclovir levels

Q20. The intracellular activation of ganciclovir to its triphosphate form requires:

• Only host cell kinases
• Initial phosphorylation by viral kinase then cellular kinases
• Activation by CYP450 enzymes
• Conversion by plasma esterases

Correct Answer: Initial phosphorylation by viral kinase then cellular kinases

Q21. Which clinical scenario is a primary indication for zidovudine therapy?

• Acute CMV encephalitis in transplant recipients
• Combination antiretroviral therapy for HIV infection
• Prophylaxis for herpes simplex labialis
• Treatment of hepatitis B infection

Correct Answer: Combination antiretroviral therapy for HIV infection

Q22. Which of the following laboratory signs suggests ganciclovir-induced myelosuppression?

• Elevated ALT and AST
• Decreased absolute neutrophil count
• Hypercalcemia
• Elevated creatine kinase

Correct Answer: Decreased absolute neutrophil count

Q23. Which viral disease is ganciclovir most specifically used to treat?

• Herpes zoster
• Cytomegalovirus (CMV) infections
• Hepatitis C
• Influenza A

Correct Answer: Cytomegalovirus (CMV) infections

Q24. Dose adjustment of ganciclovir is particularly important in patients with:

• Severe hepatic impairment only
• Renal impairment
• Hypothyroidism
• Controlled diabetes mellitus

Correct Answer: Renal impairment

Q25. Which resistance mechanism reduces zidovudine efficacy in HIV?

• Mutations in CMV UL97 gene
• Mutations in HIV reverse transcriptase that excise incorporated zidovudine
• Increased renal clearance of the drug
• Enhanced hepatic activation of zidovudine

Correct Answer: Mutations in HIV reverse transcriptase that excise incorporated zidovudine

Q26. Which clinical monitoring is least relevant for a patient on zidovudine?

• Complete blood count for anemia
• Liver function tests for hepatic injury
• Fasting lipid profile for dyslipidemia
• Assessment for lactic acidosis symptoms

Correct Answer: Fasting lipid profile for dyslipidemia

Q27. Which statement about oral bioavailability is true?

• Ganciclovir has excellent oral bioavailability similar to valganciclovir
• Valganciclovir greatly improves oral bioavailability compared to ganciclovir
• Zidovudine has no oral bioavailability and must be IV
• Both ganciclovir and zidovudine are poorly absorbed orally

Correct Answer: Valganciclovir greatly improves oral bioavailability compared to ganciclovir

Q28. Concomitant use of zidovudine with which drug class may increase risk of myopathy or mitochondrial toxicity?

• Statins
• Other nucleoside reverse transcriptase inhibitors (NRTIs)
• Beta blockers
• Proton pump inhibitors

Correct Answer: Other nucleoside reverse transcriptase inhibitors (NRTIs)

Q29. In management of CMV infection, when ganciclovir resistance is suspected due to UL97 mutation, an alternative antiviral often considered is:

• Acyclovir
• Foscarnet
• Zidovudine
• Oseltamivir

Correct Answer: Foscarnet

Q30. Which of the following best describes the role of therapeutic drug monitoring or laboratory surveillance for these antivirals?

• Not necessary because both drugs have no toxicities
• Essential to detect hematologic toxicity and manage dose adjustments based on renal/hepatic function
• Only used to measure plasma concentrations routinely
• Only required for pediatric patients

Correct Answer: Essential to detect hematologic toxicity and manage dose adjustments based on renal/hepatic function

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com