1. The percentage of hospital admissions in older adults due to drug interactions and adverse events is: a. 30% b. 60% c. 50% d. 10%
Answer : d
The elderly are the most medicated segment of the population, with the average older person taking three times more drugs compared to the young. Since there is a higher incidence of disease as we age, 80% of older adults have at least one chronic disease state. In addition, the elderly have significant changes in the physiology of many systems, which also affect the pharmacokinetics and pharmacodynamics. All of these contribute to a higher incidence of adverse events with polypharmacy in the elderly. In fact,
10% of all hospital admissions in the elderly are related to drug interactions. Pharmacotherapy is a major challenge for the health care practitioner because it is of vital importance to adjust the dosage appropriately to account for the age-related changes in older adults.
2. The parameter most likely to change in the elderly with respect to total body mass (muscle and fat) and total body water is: a. Clearance b. Volume of distribution c. Bioavailability d. Metabolism
Answer : b
Pharmacokinetics refers to the absorption, distribution, metabolism, and excretion of drugs in the body. Changes occur in these parameters with aging. With aging, the volume of distribution is decreased, which depends on total body mass (muscle and fat) and total body water. In older adults the relative proportion of lean muscle mass to total body fat is also reduced; therefore, many drugs tend to accumulate in fat with chronic dosing. Prolonged effects tend to occur since the elimination of these drugs from fatty tissue is decreased, leading to long-term exposure to the drug and potential adverse effects.
3. Pharmacodynamics refers to which one of the following pharmacological mechanisms at its particular targets?
Effects include therapeutic as well as the adverse effects.
a. Excretion of a drug b. Absorption of a drug c. Action of a drug d. Metabolism of a drug
Answer : c
When a drug is administered, it is distributed to its site of action where it is metabolized before excretion.
Pharmacodynamics refers to the pharmacological mechanism of action of a drug at its particular targets. This includes the therapeutic effects as well as the adverse effects. Various enzymes, transporters, and receptors are psychotropic drug targets that regulate the synthesis, transmission, and degradation of different chemical neurotransmitters in the central nervous system. How a drug will affect patient function overall depends on the net effect of its intended therapeutic use, together with any unintended effect on the other organ systems throughout the body. Older patients are more sensitive to the pharmacological effects of medications due to pharmacodynamic changes associated with aging.
4. The enzyme known to be inhibited by specific PPIs such as omeprazole is: a. CYP2C19 b. CYP2D6 c. CYP2C9 d. CYP1A2
C.S. Pitchumoni and T.S. Dharmarajan (eds.), Geriatric Gastroenterology,
DOI 10.1007/978-1-4419-1623-5_9, © Springer Science+Business Media, LLC 2012
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Answer : a
Omeprazole represents the best probe for CYP2C19 among the widely used PPIs. This PPI was studied in
Japanese volunteers who were given a single intravenous dose to examine the effect of aging and the pharmacokinetics of the three CYP2C19 phenotypes, poor metabolizer, intermediate metabolizer, and extensive metabolizer.
This resulted in some genotype and age-related differences in drug exposure. The AUC was more pronounced
(about twofold) in the elderly EMs and IMs but not in elderly PMs.
5. Evaluation of which of the following measures is essential before administration of most medications in an older adult?
a. Coagulation properties b. Waist circumference c. Fasting blood glucose d. Glomerular filtration rate
Answer : d
Evaluation of the GFR is essential before administration of any drug in an elderly patient. Renal function can be measured by using one of several formulae; currently these include the Cockroft–Gault formula (which approximates GFR from creatinine clearance), the MDRD equation, and the recently introduced CKD-EPI equation.
6. Various PPIs differ in their pharmacokinetic properties and concomitant intake of food or antacids, resulting in variable absorption rates and differences in which of the following?
a. Biomedicine b. Biotransformation c. Bioavailability d. Biodegradation
Answer : c
Acid-related disorders are a common problem in clinical practice with the elderly. Although as a class PPIs are highly effective, differences in their pharmacokinetics, such as bioavailability, elimination, half-life, and metabolism, may translate into different clinical outcomes. Most
PPIs have short elimination half-lives. PPIs differ in their pharmacokinetic properties; concomitant intake of food or antacids may result in variable absorption rates and differences in bioavailability.
7. With regard to drug metabolism in the elderly, the following changes in hepatic blood flow and drug extraction are best reflected by which of the following?
a. Increased; high extraction b. Decreased; low extraction c. Increased; low extraction d. Decreased; high extraction
Answer : d
Drug metabolism takes place primarily in the liver, although the small bowel may also be a site. Hepatic size and blood flow generally decline with age; therefore, high-extraction drugs might be affected by the changes.
Routine hepatic function tests do not alter with age.