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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
Correct Answer: C
Rationale: 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. Drug-enzyme interactions interfere with the enzyme systems that stimulate various chemical reactions.
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The client has a PRN prescription for loperamide hydrochloride (Imodium). The nurse understands that this medication is used for which condition?
- A. Constipation
- B. Abdominal pain
- C. An episode of diarrhea
- D. Hematest-positive nasogastric tube drainage
Correct Answer: C
Rationale: Loperamide is an antidiarrheal agent. It is used to manage acute and also chronic diarrhea in conditions such as inflammatory16inflammatory bowel disease. Loperamide also can be used to reduce the volume of drainage from an ileostomy. It is not used for the conditions in options 1, 2, and 4.
A nurse is providing instructions to the parent of an adolescent client who has a new prescription for Albuterol, PO. Which of the following instructions should the nurse include?
- A. You can take this medication to abort an acute asthma attack.
- B. Tremors are an adverse effect of this medication.
- C. Prolonged use of this medication can cause hyperglycemia.
- D. This medication can slow skeletal growth rate.
Correct Answer: B
Rationale: Tremors are a common side effect of albuterol due to beta-agonist stimulation.
Jim is being treated for hypertension. Because he has a history of heart attack, the drug chosen is atenolol. Beta blockers treat hypertension by:
- A. Increasing heart rate to improve cardiac output
- B. Reducing vascular smooth muscle tone
- C. Increasing aldosterone-mediated volume activity
- D. Reducing aqueous humor production
Correct Answer: B
Rationale: Beta blockers like atenolol reduce vascular tone and heart rate, lowering blood pressure.
Varicella vaccine is recommended to be given to patients who are:
- A. HIV positive with a CD4+ T-lymphocyte percentage less than 15%
- B. Taking corticosteroids (up to 2 mg/kg/day or less than 20 mg/day)
- C. Pregnant
- D. Immunocompromised
Correct Answer: B
Rationale: Varicella vaccine is safe with low-dose steroids; HIV with low CD4 , pregnancy , or immunocompromise contraindicate it.
Which cytochrome is responsible for drug metabolism?
- A. P-450
- B. C-3b
- C. C-3a
- D. C-2a
Correct Answer: A
Rationale: Cytochrome P-450 enzymes in the liver are primary for drug metabolism.