Bioprecursor Prodrugs Quiz
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Questions and Answers

What is the primary purpose of using sentry drugs?

  • To assist or enhance the effects of the primary drug (correct)
  • To monitor drug levels in the bloodstream
  • To replace the primary drug completely
  • To create new therapeutic drugs

    • What role does clavulanic acid play in relation to penicillins?

  • It enhances the absorption of penicillins
  • It inhibits an enzyme that deactivates penicillins (correct)
  • It increases the excretion rate of penicillins
  • It acts as a replacement for penicillins

    • How does uracil enhance the effectiveness of Tegafur in chemotherapy?

  • By converting Tegafur into a more potent drug
  • By speeding up the metabolic rate of Tegafur
  • By inhibiting the enzyme that metabolizes 5-fluorouracil (correct)
  • By increasing drug resistance in cancer cells

    • In the combination of Kaletra, what is the function of ritonavir?

    <p>To inhibit the enzyme that degrades lopinavir</p> Signup and view all the answers

    What is a prodrug, as exemplified by Tegafur?

    <p>A drug that has no effect until metabolized</p> Signup and view all the answers

    What is the primary requirement for antimetabolites that are nitrogenous base analogues to exert their effects?

    <p>They need to be converted into a triphosphate derivative.</p> Signup and view all the answers

    Which enzyme is specifically involved in the conversion of 6-Mercaptopurine to its active form?

    <p>HGPRT</p> Signup and view all the answers

    What is the action of 5-Fluorouracil once it is activated into its corresponding deoxyribonucleotide?

    <p>It inhibits thymidylate synthetase.</p> Signup and view all the answers

    Which of the following drugs also functions similarly to 5-Fluorouracil and 6-Mercaptopurine in terms of requiring activation?

    <p>Zidovudine</p> Signup and view all the answers

    The mechanism involving antimetabolites typically targets which cellular synthesis process?

    <p>De novo purine synthesis</p> Signup and view all the answers

    What is the primary reason large doses of levodopa are required for effective treatment?

    <p>It rapidly metabolizes into dopamine before entering the CNS.</p> Signup and view all the answers

    Why does carbidopa itself not affect levodopa conversion in the brain?

    <p>It cannot pass through the blood-brain barrier.</p> Signup and view all the answers

    What role does adrenaline play when combined with local anesthetics?

    <p>It constricts blood vessels to minimize the anesthetic's distribution.</p> Signup and view all the answers

    How does metoclopramide assist in the treatment of migraines when used with analgesics?

    <p>It increases gastric motility for faster absorption of the analgesic.</p> Signup and view all the answers

    What side effects may result from high doses of levodopa?

    <p>Nausea and vomiting.</p> Signup and view all the answers

    What defines a bioprecursor prodrug?

    <p>Compounds that owe their activity to oxidative or reductive metabolic products.</p> Signup and view all the answers

    Which of the following is an example of a bioprecursor prodrug and its activation mechanism?

    <p>Cyclophosphamide; metabolized to phosphoramide mustard.</p> Signup and view all the answers

    What was significant about prontosil in the context of bioprecursor prodrugs?

    <p>It acted as an antibacterial agent only after being metabolized to sulfanilamide.</p> Signup and view all the answers

    Which of the following statements regarding activation mechanisms of bioprecursor prodrugs is true?

    <p>Oxidation and reduction are common activation mechanisms.</p> Signup and view all the answers

    Which of the following prodrugs is activated by an azo reductase enzyme?

    <p>Sulphasalazine</p> Signup and view all the answers

    What characterizes a mutual prodrug?

    <p>It is made of two pharmacologically active agents that enhance each other's activity.</p> Signup and view all the answers

    Which statement about sultamicillin is true?

    <p>It combines ampicillin with a β-lactamase inhibitor.</p> Signup and view all the answers

    What is the primary challenge faced by ampicillin when used alone?

    <p>Resistance from bacteria due to high levels of β-lactamase enzymes.</p> Signup and view all the answers

    Why are mutual prodrugs like sultamicillin beneficial in treating infections?

    <p>They facilitate the simultaneous release of two active compounds that work synergistically.</p> Signup and view all the answers

    What is a key requirement for the components of an ideal mutual prodrug?

    <p>Their absorption, distribution, and elimination profiles should be similar.</p> Signup and view all the answers

    What is the primary role of Levodopa in the treatment of Parkinson's disease?

    <p>It is a prodrug that generates dopamine in the brain.</p> Signup and view all the answers

    Why can't dopamine be directly used in therapies for Parkinson's disease?

    <p>It is too polar to effectively cross the blood-brain barrier.</p> Signup and view all the answers

    What modification do GABA analogs undergo to enhance their effectiveness as anticonvulsants?

    <p>Enhancing their lipophilicity to cross the blood-brain barrier.</p> Signup and view all the answers

    What mechanism enables Levodopa to cross cell membranes?

    <p>It mimics a natural amino acid, utilizing transport proteins.</p> Signup and view all the answers

    The effectiveness of GABA analogs in treating epilepsy is primarily due to their ability to:

    <p>Cross the blood-brain barrier and release GABA in the brain.</p> Signup and view all the answers

    What is the primary reason Sulindac is considered a prodrug?

    <p>It requires metabolic conversion to become pharmacologically active.</p> Signup and view all the answers

    What is the significance of the lipophilicity of Sulindac sulfide compared to Sulindac?

    <p>It leads to a higher concentration inside the cell.</p> Signup and view all the answers

    Which of the following describes the first step in the bioactivation of Cyclophosphamide?

    <p>Hydrolysis to form a carbinolamine.</p> Signup and view all the answers

    What is a major toxic metabolite formed during the activation of Cyclophosphamide?

    <p>Acrolein.</p> Signup and view all the answers

    What is the role of the 4° Aziridinium ion in the bioactivation of Cyclophosphamide?

    <p>It is a highly reactive alkylating intermediate responsible for cytotoxicity.</p> Signup and view all the answers

    What is the pKa value of phosphoramide mustard?

    <p>4.75</p> Signup and view all the answers

    Which statement about Sulindac's action mechanism is correct?

    <p>It is reduced to a more potent sulfide metabolite.</p> Signup and view all the answers

    What differentiates Sulindac from Cyclophosphamide in terms of activation?

    <p>Cyclophosphamide requires oxidative mechanisms for activation.</p> Signup and view all the answers

    What is the primary active component that Sulfasalazine gets converted into for its therapeutic effects in inflammatory bowel disease?

    <p>5-Aminosalicylic acid</p> Signup and view all the answers

    Which statement accurately describes the pharmacokinetics of Sulfasalazine?

    <p>It is poorly absorbed and mainly acts on the distal bowel.</p> Signup and view all the answers

    What is the mechanism by which Prednimustine becomes cytotoxic?

    <p>It undergoes hydrolysis by serum esterases.</p> Signup and view all the answers

    What therapeutic use is associated with Prednimustine?

    <p>Management of chronic lymphatic leukaemia and non-Hodgkin's lymphomas</p> Signup and view all the answers

    What property does the esterification of NSAIDs, like Benorylate, significantly affect?

    <p>Suppresses gastric ulcerogenic activity</p> Signup and view all the answers

    What is the primary mechanism by which Clopidogrel and Prasugrel exert their effect on platelet aggregation?

    <p>They irreversibly bind to the P2Y12 receptor.</p> Signup and view all the answers

    Which of the following statements accurately describes the metabolic activation of Primidone?

    <p>It requires N-Oxidation metabolic activation.</p> Signup and view all the answers

    Why does Pro-2-PAM readily enter the central nervous system (CNS)?

    <p>It is uncharged and hydrophilic, facilitating uptake.</p> Signup and view all the answers

    What is the effect of Clopidogrel and Prasugrel lasting for 7-10 days after discontinuation?

    <p>Prevents reactivation of platelet aggregation.</p> Signup and view all the answers

    Which of the following best describes the relationship between 2-PAM and its prodrug form?

    <p>The charge of 2-PAM restricts its transfer from the CNS.</p> Signup and view all the answers

    Study Notes

    Bioprecursor Prodrugs

    • Normal prodrugs rely on hydrolysis reactions for effectiveness.
    • Bioprecursor prodrugs use either oxidative or reductive activation to become active.
    • Bioprecursor prodrugs are inactive until activation.
    • The birth of bioprecursors occurred when the agent was demonstrated to be an actual drug.
    • Examples of bioprecursor prodrugs: Prontosil, sulfasalazine, cyclophosphamide, L-DOPA, chloroguanide, primidone, sulindac, and Pro-2-PAM.

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    Description

    Test your knowledge on bioprecursor prodrugs, their mechanisms, and examples. Learn how these prodrugs differ from traditional ones and their activation processes. Explore the significance of bioprecursor prodrugs in pharmacology.

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