An antagonist is a drug that prevents receptor activation. A selective drug has only the desired response but may not activate receptors. An agonist is a
... [Show More] molecule that activates receptors. A potent drug requires a lower dose to achieve its effect. Answer- The nurse prepares to give a drug that will prevent receptor activation. Which term would describe this drug?
A. Potent
B. Agonist
C. Selective
D. Antagonist
C. Pharmacodynamics
***Pharmacodynamics is the study of what drugs do to the body. Pharmacokinetics is the study of drug movement throughout the body. Pharmacotherapeutics is the use of drugs to diagnose, prevent, or treat disease or to prevent pregnancy. Pharmacology is the study of drugs in humans. Answer- What is the term for the study of how drugs influence the body?
A. Pharmacology
B. Pharmacokinetics
C. Pharmacodynamics
D. Pharmacotherapeutics
D. The highest dose needed to produce a therapeutic effect is close to the lethal dose.
***A low therapeutic index indicates that the high doses needed to produce therapeutic effects in some people may be large enough to cause death. A high therapeutic index is more desirable, because the average lethal dose is higher than the therapeutic dose. Low variability of responses to a drug is not the definition of a low therapeutic index. Answer- Why does the nurse monitor the patient closely after administering a drug with a low therapeutic index?
A. There is a low variability of responses to this drug.
B. The average lethal dose of the drug is much higher than the therapeutic dose.
C. The dose required to produce a therapeutic response in 50% of patients is low.
D. The highest dose needed to produce a therapeutic effect is close to the lethal dose.
A. Monitor the patient's plasma drug level periodically.
***The therapeutic range of a drug is the range between the minimum effective concentration of the drug in the plasma to obtain the desired drug action and the minimum toxic concentration. The nurse must monitor the plasma drug level periodically to avoid drug toxicity while caring for a patient receiving a drug with a low therapeutic index, such as digoxin. Some medications, such as diphenhydramine [Benadryl], cause drowsiness as a side effect. In such cases, the nurse instructs patients not to drive after taking the medication. Some drugs bind to the protein molecules in the body. The nurse monitors serum albumin levels in patients receiving those drugs to determine the possibility of drug toxicity. Patients who are prescribed enteric-coated tablets should not eat a high-fat meal before taking the drug, as that will decrease the absorption rate of the drug. Answer- The nurse is caring for a patient who is receiving a drug with a low therapeutic index. Which is the most important nursing intervention for this patient?
A. Monitor the patient's plasma drug level periodically.
B. Monitor the patient's serum albumin levels periodically.
C. Instruct the patient not to drive after taking the medication.
D. Instruct the patient not to take the drug after a high-fat meal.
B. Increased heart rate
***Dobutamine mimics the action of norepinephrine (NE) at receptors on the heart, thereby causing an increase in the heart's rate and force of contraction. Answer- The drug dobutamine acts as an agonist of norepinephrine (NE) receptors. Which effect is the nurse most likely to observe in a patient receiving this medication?
A. Sinus bradycardia
B. Increased heart rate
C. Reduced cardiac output
D. Atrioventricular heart block
B. Antagonist
***An antagonist drug is one that blocks the histamine receptors to prevent excessive gastric secretion. Drugs that produce a response are called agonists. For example, epinephrine [Adrenalin] is an agonist that stimulates beta1 and beta2 receptors. Nonspecific drugs affect various sites in the body. Bethanechol [Urecholine] is a nonspecific cholinergic drug that affects cholinergic receptors located in the eye, heart, blood vessels, stomach, bronchus, and bladder. Nonselective drugs affect various receptors. Chlorpromazine [Thorazine] acts on the norepinephrine, dopamine, acetylcholine, and histamine receptors, and a variety of responses result from action at these receptor sites. Answer- The nurse is caring for a patient who is prescribed a drug to block the histamine receptors to prevent excessive gastric secretion. Which category of drugs does this medication belong to?
A. Agonist
B. Antagonist
C. Nonspecific
D. Nonselective
A. Antacids
***Antacids do not act through receptors. Antacids neutralize gastric activity by direct chemical interaction with stomach acid. Answer- The nursing student learns that not all drugs produce effects by binding to a receptor. Which drugs do not act through receptors?
A. Antacids
B. Analgesics
C. Antihistamines
D. Steroid hormones
A. Bronchial dilation
B. Increased heart rate
F. Increased force of heart contraction
***Activation of beta1 and beta2 receptors results in dilation of the bronchi, increased cardiac output (by increasing the heart rate and force of contraction); and elevation of the blood glucose level. Answer- The nurse is administering isoproterenol, a beta1 and beta2 agonist. The nurse understands activation of these two receptors will result in which expected drug effects? Select all that apply.
A. Bronchial dilation
B. Increased heart rate
C. Excessive drowsiness
D. Decreased cardiac output
E. Decreased glucose levels
F. Increased force of heart contraction
D. An effect that mimics the natural neurotransmitter for that receptor
***Receptor activation is an effect on receptor function equivalent to that produced by the natural neurotransmitter at a particular synapse. Activation of a receptor may slow down or speed up the process, depending on the function of that particular receptor. Activation does not have to do with improving receptor function or sensitivity. Answer- Which phrase best describes activation of a receptor?
A. An effect that improves the function of the receptor
B. An effect that causes the receptor to be more sensitive
C. An effect that causes the physiologic process to speed up
D. An effect that mimics the natural neurotransmitter for that receptor
B. Reuptake of the transmitter
***5a is an image for reuptake of the transmitter into the nerve terminal; 2 is storage of the transmitter; 1 is synthesis of the transmitter; and 5b is enzymatic degradation of the transmitter. Answer- A nurse is teaching the staff about the effects of drugs on receptor activity. The nurse is using the image in the teaching session. Which concept will the nurse teach about for 5a in the image?
A. Storage of the transmitter
B. Reuptake of the transmitter
C. Synthesis of the transmitter
D. Enzymatic degradation of the transmitter
B. "Agonist drugs decrease receptor activation."
***Drugs that directly activate receptors are called agonists, whereas drugs that prevent receptor activation are called antagonists. Local anesthetics are drugs that work by altering/suppressing axonal conduction. Answer- A nurse is teaching a group of coworkers about the effects of drugs on receptors. Which comment by a coworker would need correction?
A. "Agonist drugs increase receptor activation."
B. "Agonist drugs decrease receptor activation."
C. "Antagonist drugs decrease receptor activation."
D. "Local anesthetics suppress axonal conduction."
C. Higher degree of selectivity
***Selectivity is one of the most desirable qualities a drug can have. Many neuropharmacologic drugs are highly selective, because the nervous system works through multiple receptors to regulate processes under its control. Answer- What is the advantage of patients having multiple types of receptors to regulate bodily functions?
A. Lower therapeutic index
B. Improved maximal efficacy
C. Higher degree of selectivity
D. Reduction of side effects and toxicity
A. Release of renin
B. Increased heart rate
D. Increased AV conduction velocity
***Beta1 receptors are located in the heart and the kidney. The response to receptor activation will result in increased heart rate, increased force of contraction of heart, increased AV conduction velocity, and release of renin. It is beta2 receptors that result in dilation of arterioles. Answer- The nurse is reviewing medications that act as beta1 receptors. Which of these are responses to beta1 receptor activation? Select all that apply.
A. Release of renin
B. Increased heart rate
C. Dilation of arterioles
D. Increased AV conduction velocity
E. Decreased force of contraction of heart
D. Sympathetic nerves to sweat glands promotes secretion of sweat
E. Piloerection induced by sympathetic nerves causes heat conservation
***The sympathetic nervous system helps regulate body temperature in three ways. (1) By regulating blood flow to the skin, sympathetic nerves can increase or decrease heat loss. By dilating surface vessels, sympathetic nerves increase blood flow to the skin and thereby accelerate heat loss. Conversely, constricting cutaneous vessels conserves heat. (2) Sympathetic nerves to sweat glands promote secretion of sweat, thereby helping the body cool. (3) By inducing piloerection (erection of hair), sympathetic nerves can promote heat conservation. Answer- By which of these ways does the sympathetic nervous system (SNS) help to regulate body temperature? Select all that apply.
A. By dilating cutaneous vessels to conserve heat
B. By compensating for blood loss by causing vasoconstriction
C. By constricting surface vessels to increase blood flow to the skin
D. Sympathetic nerves to sweat glands promotes secretion of sweat
E. Piloerection induced by sympathetic nerves causes heat conservation
A. It maintains the body temperature.
C. It regulates the cardiovascular system.
D. It implements the "fight-or-flight" reaction.
***The functions of the sympathetic nervous system include regulating the cardiovascular system, implementing the fight-or-flight reaction, and maintaining the body temperature. The sympathetic nervous system dilates bronchial smooth muscles. The parasympathetic nervous system is responsible for controlling the amount of gastric secretions. Answer- The nurse is teaching a patient about the functions of the sympathetic nervous system related to a prescribed medication. What should the nurse tell the patient about the functions of this system? Select all that apply.
A. It maintains the body temperature.
B. It alters the secretion of gastric juices.
C. It regulates the cardiovascular system.
D. It implements the "fight-or-flight" reaction.
E. It constricts the bronchial smooth muscles.
B. Stimulation of sympathetic nerves to veins causes vasoconstriction.
***Stimulation of sympathetic nerves to arteries and veins causes vasoconstriction; stimulation to the heart causes increased cardiac output, and stimulation to the adrenal medulla causes vasoconstriction in vascular beds. Answer- The nurse is reviewing the sympathetic nervous system (SNS) effects on the heart and blood vessels. Which statement is correct regarding the effect of SNS stimulation?
A. Stimulation of sympathetic nerves to arteries causes vasodilation.
B. Stimulation of sympathetic nerves to veins causes vasoconstriction.
C. Stimulation of sympathetic nerves to the heart decreases cardiac output.
D. Stimulation of sympathetic nerves to the adrenal medulla causes increased heart rate.
B. Beta1
C. Nicotinic
***Beta1 receptors affect the heart by increasing the heart rate. Nicotinic receptors release epinephrine, which can increase heart rate. Alpha1 receptors are present on veins and on arterioles in many capillary beds. Activation of alpha1 receptors in blood vessels produces vasoconstriction, which can increase cardiac output and blood pressure, but not heart rate. Dopamine causes vasodilation, which decreases heart rate. Muscarinic receptors decrease heart rate. Answer- The patient with a heart rate of 48 beats/min has been prescribed a medication to increase heart rate. The nurse recalls that which activated receptors can increase heart rate? Select all that apply.
A. Alpha1
B. Beta1
C. Nicotinic
D. Dopamine
E. Muscarinic
B. Baroreceptor reflex
***From a pharmacologic perspective, the baroreceptor reflex is the most important feedback loop of the autonomic nervous system. This reflex is important because it frequently opposes our attempts to modify blood pressure with drugs. Autonomic tone is the steady, day-to-day influence exerted by the autonomic nervous system on a particular organ or organ system. Innervation refers to how nerves affect systems in the body and are not directly related to pharmacologic effects. Sensor and effector response are processes within every feedback loop. Answer- A nurse is teaching a group of students about pharmacologic effects of the feedback loop on the autonomic nervous system. What will the nurse teach is the most important feedback loop?
A. Autonomic tone
B. Baroreceptor reflex
C. Patterns of innervation
D. Sensor and effector response
B. Sympathetic system
***Stimulation of the sympathetic nervous system produces the fight-or-flight response. The baroreceptor reflex regulates blood pressure. Answer- A patient is experiencing symptoms of the fight-or-flight response. Which autonomic process stimulates this response?
A. Baroreceptor reflex
B. Sympathetic system
C. Parasympathetic system
D. Predominant tone of the organs
C. Postural hypotension
***The main adverse effect of cholinergic drugs in the patient is postural hypotension, which results in dizziness and fainting. This effect can be decreased by changing positions slowly when standing. These drugs do not affect muscular function, gastrointestinal function, or respiratory function. Therefore, muscle cramps, nausea or vomiting, and dyspnea are not adverse effects related to cholinergic drugs. Answer- The nurse advises a patient who is taking cholinergic drugs to avoid standing quickly and to rise to an upright position slowly. Which complication associated with the drug is the nurse trying to prevent?
A. Dyspnea
B. Muscle cramps
C. Postural hypotension
D. Nausea and vomiting
C. Reduction of cardiac output [Show Less]