Protease inhibitors – Saquinavir, Indinavir, Ritonavir MCQs With Answer

Protease inhibitors – Saquinavir, Indinavir, Ritonavir MCQs With Answer

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Protease inhibitors – Saquinavir, Indinavir, Ritonavir MCQs With Answer

Protease inhibitors (PIs) are cornerstone antiretroviral agents that block HIV-1 protease, preventing maturation of viral particles. Saquinavir, Indinavir and Ritonavir are first-generation PIs with distinct pharmacokinetics, adverse effects and drug interactions important for B. Pharm students. Learn the mechanism of action, CYP3A4 metabolism, ritonavir boosting, resistance mutations, nephrolithiasis with indinavir, QT/PR effects, lipid and glucose abnormalities, dosing, monitoring and clinically relevant interactions (e.g., statins, rifampicin). This focused review emphasizes clinical application, therapeutic drug monitoring and safe dispensing practices. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which of the following best describes the primary mechanism of action of protease inhibitors like saquinavir, indinavir and ritonavir?

  • Inhibition of reverse transcriptase enzyme
  • Blocking entry of HIV into host cells
  • Inhibition of HIV-1 protease preventing cleavage of Gag-Pol polyprotein
  • Integration of viral DNA into host genome

Correct Answer: Inhibition of HIV-1 protease preventing cleavage of Gag-Pol polyprotein

Q2. Ritonavir is commonly used in modern antiretroviral therapy primarily because it:

  • Has the strongest independent antiretroviral activity among PIs
  • Acts as a potent CYP3A4 inhibitor to boost plasma levels of other PIs
  • Directly prevents viral entry
  • Is free of metabolic adverse effects

Correct Answer: Acts as a potent CYP3A4 inhibitor to boost plasma levels of other PIs

Q3. A distinctive adverse effect associated with indinavir is:

  • Severe QT prolongation
  • Nephrolithiasis and crystalluria
  • Bone marrow suppression
  • Optic neuritis

Correct Answer: Nephrolithiasis and crystalluria

Q4. Saquinavir bioavailability is significantly increased when administered:

  • With a high-fat meal
  • On an empty stomach only
  • With proton pump inhibitors
  • Via intravenous infusion

Correct Answer: With a high-fat meal

Q5. Which CYP enzyme primarily metabolizes most protease inhibitors including saquinavir, indinavir and ritonavir?

  • CYP2D6
  • CYP1A2
  • CYP3A4
  • CYP2C9

Correct Answer: CYP3A4

Q6. The rationale for “ritonavir boosting” is to:

  • Increase renal excretion of other PIs
  • Induce hepatic enzymes to lower other PI levels
  • Inhibit hepatic metabolism of coadministered PIs, increasing their AUC
  • Prevent protease inhibitor resistance mutations

Correct Answer: Inhibit hepatic metabolism of coadministered PIs, increasing their AUC

Q7. Which PI is most associated with marked elevations in triglycerides and lipodystrophy?

  • Saquinavir
  • Indinavir
  • Ritonavir
  • None of the above

Correct Answer: Ritonavir

Q8. Indinavir dosing advice to reduce risk of nephrolithiasis includes:

  • Avoid adequate hydration to prevent dilution
  • Take with a large fatty meal
  • Maintain high fluid intake and take on an empty stomach as recommended
  • Co-administer with antacids only

Correct Answer: Maintain high fluid intake and take on an empty stomach as recommended

Q9. An important drug interaction with ritonavir is contraindication with:

  • Atorvastatin at low dose
  • Simvastatin due to risk of severe myopathy and rhabdomyolysis
  • Acetaminophen
  • Metformin at usual dose

Correct Answer: Simvastatin due to risk of severe myopathy and rhabdomyolysis

Q10. Resistance to protease inhibitors most commonly arises from:

  • Mutations in reverse transcriptase gene
  • Mutations in the protease active site and substrate cleft
  • Enhanced drug efflux only
  • Horizontal gene transfer

Correct Answer: Mutations in the protease active site and substrate cleft

Q11. Which monitoring parameter is most important when a patient is on ritonavir-boosted PI therapy?

  • Complete blood count weekly
  • Lipid profile and liver function tests periodically
  • Serum amylase monthly
  • Serum magnesium only

Correct Answer: Lipid profile and liver function tests periodically

Q12. Saquinavir is best described as:

  • A nucleoside reverse transcriptase inhibitor
  • A first-generation protease inhibitor with low oral bioavailability improved by boosting
  • A non-nucleoside protease inhibitor
  • An integrase inhibitor

Correct Answer: A first-generation protease inhibitor with low oral bioavailability improved by boosting

Q13. Which adverse effect is classically linked to protease inhibitors as a group?

  • Peripheral neuropathy without metabolic changes
  • Lipodystrophy, insulin resistance and dyslipidemia
  • Pancytopenia as the main toxicity
  • Severe neutrophilia

Correct Answer: Lipodystrophy, insulin resistance and dyslipidemia

Q14. When switching from rifampicin to rifabutin in a patient on ritonavir-boosted PI, the main reason is:

  • Both rifamycins have identical interactions
  • Rifampicin is a strong CYP3A4 inducer that lowers PI levels; rifabutin has less induction
  • Rifabutin causes more severe interactions with PIs
  • Rifampicin increases PI half-life

Correct Answer: Rifampicin is a strong CYP3A4 inducer that lowers PI levels; rifabutin has less induction

Q15. Which statement about therapeutic drug monitoring (TDM) of protease inhibitors is correct?

  • TDM is never useful for PIs
  • TDM can help optimize dosing in patients with variable absorption, drug interactions or adherence concerns
  • TDM replaces the need for viral load monitoring
  • TDM is useful only for indinavir due to stone risk

Correct Answer: TDM can help optimize dosing in patients with variable absorption, drug interactions or adherence concerns

Q16. A patient on indinavir presents with flank pain and hematuria. The most likely cause is:

  • Acute interstitial nephritis
  • Indinavir-induced nephrolithiasis due to urinary precipitation of the drug
  • Renal cell carcinoma
  • Prostatic hypertrophy

Correct Answer: Indinavir-induced nephrolithiasis due to urinary precipitation of the drug

Q17. Which PI is most notably associated with PR and QT interval prolongation?

  • Indinavir
  • Saquinavir
  • Zidovudine
  • Lamivudine

Correct Answer: Saquinavir

Q18. In the context of antiretroviral therapy, cobicistat differs from ritonavir because cobicistat:

  • Is an antiretroviral protease inhibitor itself
  • Has no antiretroviral activity and is used solely as a pharmacokinetic booster
  • Is a potent inducer of CYP3A4
  • Causes nephrolithiasis like indinavir

Correct Answer: Has no antiretroviral activity and is used solely as a pharmacokinetic booster

Q19. Which of the following clinical uses is most appropriate for ritonavir today?

  • Monotherapy for HIV infection
  • Low-dose pharmacokinetic booster for other PIs
  • Primary therapy for opportunistic infections
  • Management of acute hepatitis C

Correct Answer: Low-dose pharmacokinetic booster for other PIs

Q20. A major counseling point for patients starting indinavir is:

  • Avoid fluids to reduce urine drug concentration
  • Increase fluid intake to at least 1.5–2 liters/day to prevent kidney stones
  • Take with dairy to improve absorption
  • Stop other medications without consulting a clinician

Correct Answer: Increase fluid intake to at least 1.5–2 liters/day to prevent kidney stones

Q21. Which lab abnormality is most directly associated with protease inhibitor therapy?

  • Hypolipidemia
  • Hypertriglyceridemia and elevated LDL cholesterol
  • Severe hypoglycemia
  • Marked eosinophilia

Correct Answer: Hypertriglyceridemia and elevated LDL cholesterol

Q22. Which statement about saquinavir resistance is true?

  • Resistance cannot develop to saquinavir
  • Single mutations always abolish activity; multi-mutation patterns create high-level resistance
  • Resistance is only related to reverse transcriptase mutations
  • Resistance is mediated by reduced renal excretion

Correct Answer: Single mutations always abolish activity; multi-mutation patterns create high-level resistance

Q23. Which dosing consideration is important for saquinavir when used without a booster?

  • It achieves high plasma levels without boosting
  • It has low oral bioavailability and is typically given with ritonavir to improve levels
  • It must be given intravenously only
  • It is only active against hepatitis viruses

Correct Answer: It has low oral bioavailability and is typically given with ritonavir to improve levels

Q24. The chemical basis for protease inhibitor activity is that they:

  • Are nucleoside analogues incorporated into viral DNA
  • Mimic the transition state of peptide bond cleavage and bind the protease active site
  • Disrupt viral envelope fusion by altering membrane lipids
  • Act as monoclonal antibodies against protease

Correct Answer: Mimic the transition state of peptide bond cleavage and bind the protease active site

Q25. Which adverse endocrine/metabolic effect should pharmacists warn patients about when taking PIs?

  • Persistent hypolipidemia
  • New-onset diabetes mellitus or insulin resistance
  • Decreased appetite and weight loss only
  • Hypothyroidism

Correct Answer: New-onset diabetes mellitus or insulin resistance

Q26. Which of the following antimicrobials is contraindicated or requires adjustment when coadministered with ritonavir due to CYP interactions?

  • Azithromycin with no precautions
  • Clarithromycin without dose change
  • Voriconazole without monitoring
  • Rifampicin should be avoided due to potent induction of CYP3A4

Correct Answer: Rifampicin should be avoided due to potent induction of CYP3A4

Q27. Cross-resistance among protease inhibitors implies that:

  • Resistance to one PI never affects others
  • Certain protease mutations can reduce susceptibility to multiple PIs
  • Resistance develops only to NNRTIs
  • PIs remain effective irrespective of mutation patterns

Correct Answer: Certain protease mutations can reduce susceptibility to multiple PIs

Q28. A patient on ritonavir reports numbness and altered taste; this adverse effect is most consistent with:

  • Cardiac toxicity typical of saquinavir
  • Neuropsychiatric adverse effects unrelated to PIs
  • Known ritonavir-associated paresthesias and taste disturbance
  • Classic sign of indinavir nephrolithiasis

Correct Answer: Known ritonavir-associated paresthesias and taste disturbance

Q29. Which statement about protease inhibitor use in pregnancy is correct?

  • PIs are absolutely contraindicated in all trimesters
  • Certain PIs, especially when boosted, are used in pregnancy but require specialist input and monitoring
  • PIs completely prevent vertical transmission without other measures
  • PIs have no interactions and do not require monitoring during pregnancy

Correct Answer: Certain PIs, especially when boosted, are used in pregnancy but require specialist input and monitoring

Q30. For a B. Pharm student counseling a patient, which practical advice is essential for those on ritonavir-boosted regimens?

  • There are no important drug interactions to consider
  • Always check for CYP3A4-metabolized drugs, advise lipid and glucose monitoring and counsel on adherence
  • Advise stopping other chronic medications while on PIs
  • Recommend unlimited grapefruit juice to improve absorption

Correct Answer: Always check for CYP3A4-metabolized drugs, advise lipid and glucose monitoring and counsel on adherence

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