Exam (elaborations)
Chapter 2 Drug–Receptor Interactions and Pharmacodynamics
- Course
- Pharmacology illustrated
- Institution
- Plaza College
Chapter 2 Drug–Receptor Interactions and Pharmacodynamics
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1. Chapter 2: Drug–Receptor Interactions andPharmacodynamics
1. Drugs do not metabolize the same way in all people. For what patient would a nurse
expect to assess for an alteration in drug metabolism?
A) A 35-year-old woman with cervical cancer
B) A 41-year-old man with kidney stones
C) A 50-year-old man with cirrhosis of the liver
D) A 62-year-old woman in acute renal failure
Ans: C
Feedback:
The liver is the most important site of drug metabolism. If the liver is not functioning
effectively, as in patients with cirrhosis, drugs will not metabolize normally so that toxic
levels could develop unless dosage is reduced. A patient with cervical cancer or kidney
stones would not be expected to have altered ability to metabolize drugs so long as no
liver damage existed. The patient with renal failure would have altered excretion of the
drugs through the renal system but metabolism would not be impacted.
2. A patient presents to the emergency department with a drug level of 50 units/mL. The
half-life of this drug is 1 hour. With this drug, concentrations above 25 units/mL are
considered toxic and no more drug is given. How long will it take for the blood level
to reach the non-toxic range?
A) 30 minutes
B) 1 hour
C) 2 hours
D) 3 hours
Ans: B
Feedback:
Half-life is the time required for the serum concentration of a drug to decrease by 50%.
After 1 hour, the serum concentration would be 25 units/mL (50/2) if the body can
properly metabolize and excrete the drug. After 2 hours, the serum concentration would
be 12.5 units/mL (25/2) and reach the nontoxic range. In 30 minutes the drug level
would be 37.5 units/mL, whereas in 3 hours the drug level would be 6.25.
, 3. A patient has recently moved from Vermont to Southern Florida. The patient presents to
the clinic complaining of dizzy spells and weakness. While conducting the admission
assessment, the patient tells the nurse that he have been on the same antihypertensive
drug for 6 years and had stable blood pressures and no adverse effects. Since his move,
he has been having problems and he feels that the drug is no longer effective. The clinic
nurse knows that one possible reason for the change in the effectiveness of the drug
could be what?
A) The impact of the placebo effect on the patients response.
B) The accumulative effect of the drug if it has been taken for many years.
C) The impact of the warmer environment on the patients physical status.
D) Problems with patient compliance with the drug regimen while on vacation.
Ans: C
Feedback:
Antihypertensive drugs work to decrease the blood pressure. When a patient goes to a
climate that is much warmer than usual, blood vessels dilate and the blood pressure falls.
If a patient is taking an antihypertensive drug and moves to a warmer climate, there is a
chance that the patients blood pressure will drop too low, resulting in dizziness and
feelings of weakness. Even mild dehydration could exacerbate these effects. Most
antihypertensives are metabolized and excreted and do not accumulate in the body.
Patients must be very compliant with their drug regimen on vacation. After several years
on an antihypertensive drug, the effects of that drug are known; therefore, the placebo
effect should not be an issue.
4. An important concept taught by the nurse when providing medication teaching is the need to
provide a complete list of medications taken to health care providers to avoid what?
A) Spending large amounts of money on medications
B) Allergic reactions to medications
C) Drugdrug interactions
D) Critical concentrations of medications in the body
Ans: C
Feedback:
It is important that all health care providers have a complete list of the patients
medications to avoid drugdrug interactions caused by one provider ordering a
medication, unaware of another medication the patient is taking that could interact with
, the new prescription. Using the same pharmacist for all prescriptions will also help to
prevent this from happening. Informing the provider of all medications taken will not
reduce costs of medications, which is best accomplished by requesting generic
medications. Allergies should be disclosed to all health care providers as well, but this is
not why it is important to provide a complete list of medications taken. Critical
concentrations are desirable because that is the amount of drug needed to cause a
therapeutic effect, or, in other words, to have the effect the drug is prescribed for.
5. A pharmacology student asks the instructor what an accurate description of a drug
agonist is. What is the instructors best response?
A) A drug that reacts with a receptor site on a cell preventing a reaction with another
chemical on a different receptor site
B) A drug that interferes with the enzyme systems that act as catalyst for different
chemical reactions
C) A drug that interacts directly with receptor sites to cause the same activity that a
natural chemical would cause at that site
D) A drug that reacts with receptor sites to block normal stimulation, producing no
effect
Ans: C
Feedback:
Agonists are drugs that produce effects similar to those produced by naturally occurring
neurotransmitters, hormones, or other substances found in the body. Noncompetitive
antagonists are drugs that react with some receptor sites preventing the reaction of
another chemical with a different receptor site. Drugenzyme interactions interfere with
the enzyme systems that stimulate various chemical reactions.
6. A nurse is caring for a patient who has been receiving a drug by the intramuscular route
but will receive the drug orally after discharge. How does the nurse explain the
increased dosage prescribed for the oral dose?
A) Passive diffusion
B) Active transport
C) Glomerular filtration
D) First-pass effect
Ans: D
Feedback:
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