Nucleotides Exam 2- James

Fill in the blanks: Pre-systemic biotransformation, also known as _______ biotransformation, can occur in the _______ and the ______ for orally administered drugs
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1. Drug w/ MW 285: would undergo entero-hepatic cycling because (285 +176 > 400)
Drug w/ MW 151: would not undergo entero-hepatic cycling because (151 + 176 < 400)
2. The glucuronide will be excreted in bile and enter the intestine where in the lower intestine B-glucuronidase will convert the drug-glucuronide to the parent drug, which is reabsorbed.
3. Prolong duration of action
The following reaction occurs at a very slow rate in some individual patients and a very rapid rate in other individuals, compared with the majority of people.
1. Explain why this is the case.
2. Name the enzyme that carries out the reaction.
3. Approximately what percentage of an average US population would carry out this reaction very slowly.
Fill in the blanks: Administration of the drug Interferon to fight a viral illness could result in ______ amounts of CYP2 and CYP3 family isozymes in liver and thus ______ the ability of the patient to metabolize common drugs.decreased reduceWhich pathways of drug biotransformation would be less efficient in patients who eat low protein diets.Glutathione conjugation and amino acid conjucationWhy is it beneficial for an HIV-positive patient to take ritonavir along with indinavir?Both drugs are substrates for CYP3A4 the ritonavir will bind to CYP3A4 in intestine and liver and result in increased bioavailability of the indinavirPatient's are cautioned not to take certain drugs with grapefruit juice. Why?Grapefruit juice contains natural products that inhibit CYP3A4 and p-glycoprotein in intestine and could thus alter drug bioavailabilityThe following anxiolytic drug (lorazepam, MW 321) can be given orally. 1. What major metabolite would you expect from this drug and how would you expect it to be excreted? 2. The graph on the right shows the blood level of the free drug after oral administration- describe and name the process that could explain the spike shown between 2 and 4 hours after the dose?1. Lorazepam glucuronide, excreted in bile 2. Entero-hepatic cycling. The glucuronide is formed in liver and excreted in bile, which is secreted into the intestines. As the glucuronide passes down the GI tract glucuronidase enzymes in the intestine convert the glucuronide conjugate to glucuronic acid and free lorazepam. The lorazepam is reabsorbed and a portion reaches the blood.List the two important properties of a drug molecule that can be altered by the process of biotransformation. For each property listed state the most common result of this alternation by biotransformation.Lipid solubility - converted to greater water solubility Pharmacological activity - commonly lost or changed by biotransformation Toxicity - may be increasedExplain what is meant by the term "genetic polymorphism".Change in a nucleotide of a gene from one person to another.Give two reasons why an individual patient may show slow metabolism of a drug that is mainly cleared by UDP-glucuronosyltransferase 1A1?1. If the patient is a newborn 2. If the patient has Gilbert's syndromeIf an asthmatic patient complained that their usual dose of theophylline was no longer effective, what question could you ask to find out if it was likely that the patient's metabolism of theophylline (Catalyzed by CYP1A2) had changed?Have you been exposed to smoke? Have you eaten a lot of charcoal-broiled food?How could a viral infection affect drug biotransformation in an individual patient and why?Viral infections result in release of cytokines which can suppress (down-regulate) CP450 enzyme synthesis, resulting in slower drug biotransformation.Give on reason why acute injection of a large amount of ethanol could affect the biotransformation of a drug that is metabolized by CP450?The ethanol can use up NADPH in liver so that there is not enough to support normal rates of CP450 catalyzed drug biotransformation