Pharmacology - Chapter 2

________________ is the process that occurs from the time a drug enters the body to the time it enters the bloodstream to be circulated.

Absorption

The client is taking a 2-mg dose of ropinirole XR. The drug has a half-life of 12 hours. In how many hours will 0.25 mg of this drug remain in the client's system?

Answer: 36 Rationale: The half-life of a drug is the time it takes for the amount of drug in the body to decrease to half of the peak level it previously achieved. At 12 hours, there will be 1 mg of the drug available to the body. At 24 hours, there will be 0.5 mg; at 36 hours, there will be 0.25 mg; at 48 hours, there will be 0.125 mg, and at 60 hours, there will be 0.0625 mg.

A nurse is looking up information about the effects of a drug on different receptors. Characteristics of receptors include which of the following? A. They are carbohydrates located in cell membranes or inside cells. B. They are constantly synthesized and degraded in the body. C. They bind with molecules of any drug circulating in the bloodstream. D. They regulate the actions of all drugs.

D. They regulate the actions of all drugs. Rationale: Receptors are mainly proteins that are manufactured and eliminated like other proteins in the body. Their numbers and binding capacities can be increased or decreased in particular situations. Most receptors bind with relatively few drugs. Some drugs do not require receptor binding for their actions (e.g., antacids such as TUMS or Mylanta).

__________ are used in clinical drug trials to compare the medication being tested with a "dummy" medication.

Placebos

Ingesting tyramine-containing foods with MAO inhibitors may produce severe hypertension. a. TRUE b. FALSE

a. TRUE

What client is most likely to have impaired drug metabolism? a. A client who requires dialysis for renal failure b. A client who has a diagnosis of hepatitis C c. A client who is dehydrated following several days of diarrhea d. A client who is being treated for basal cell skin cancer

b. A client who has a diagnosis of hepatitis C Rationale: The liver is the single most important site of drug metabolism. The skin plays a role in drug excretion. The kidneys play the most important role in drug excretion. The feces via the bowel play a role in drug excretion.

What function is associated with metabolism? a. Aiding in the absorption of a drug b. Initiating the process of digestion c. Converting fat-soluble drugs into water-soluble forms d. Inhibiting cell function by occupying receptor sites

c. Converting fat-soluble drugs into water-soluble forms Rationale: Most drugs are lipid soluble, which aids movement across cell membranes; however, kidneys can only excrete water-soluble substances. Therefore, metabolism of the drug includes conversion from lipid-soluble substances to water-soluble substances for elimination. The process of metabolism is not responsible for initiating digestion or absorption, as these precede metabolism. Drug antagonists occupy receptor sites.

Activated __________ is considered the "universal" antidote.

charcoal

During pregnancy, drugs cross the __________________ and may harm the fetus.

placenta

A client's most recent laboratory result indicates an elevated potassium level. What drug in this client's medication regimen should the care team consider discontinuing? a. A diuretic b. An antianxiety agent c. An antipsychotic d. A narcotic

a. A diuretic Rationale: Elevated potassium levels can result from the use of certain diuretics. Narcotics, antipsychotics, and antianxiety drugs are not associated with this adverse effect.

The nurse is explaining to the client what bioavailability is. What statement is true of bioavailability? a. It is the portion of a dose that reaches the systemic circulation and is available to act on body cells. b. It is the portion of a dose that is absorbed by the system to achieve a therapeutic drug level. c. It is the portion of a dose that reaches the systemic circulation. d. It is the portion of a dose that causes toxicity.

a. It is the portion of a dose that reaches the systemic circulation and is available to act on body cells. Rationale: Bioavailability is the portion of a dose that reaches the systemic circulation and is available to act on body cells.

Naloxone is used to relieve respiratory depression associated with morphine. a. TRUE b. FALSE

a. TRUE

The nurse is caring for a diverse group of clients. In which client should the nurse assess for an alteration in drug metabolism? a. 35-year-old female with cervical cancer b. 50-year-old male with cirrhosis of the liver c. 41-year-old male with kidney stones d. 32-year-old female with urosepsis

b. 50-year-old male with cirrhosis of the liver Rationale: The liver is the most important site of drug metabolism. If the liver is not functioning effectively, as in clients with cirrhosis, drugs will not metabolize normally so that toxic levels could develop unless dosage is reduced. A client with cervical cancer or kidney stones would not be expected to have altered ability to metabolize drugs so long as no liver damage existed. Infections such as urosepsis would not have a direct impact on metabolism.

Distribution is the method by which drugs are inactivated or biotransferred by the body. a. TRUE b. FALSE

b. FALSE

Hyperthyroidism slows metabolism, which shortens drug action and hastens elimination. a. TRUE b. FALSE

b. FALSE

A female client has a 12-year history of ETOH abuse. The client is injured in a motor vehicle accident and requires surgery with general anesthesia. What would the nurse expect for this client? a. No general anesthesia, because general anesthesia should not be given to a client with her history b. A smaller-than-normal dose of the general anesthetic c. A larger-than-normal dose of the general anesthetic d. The same dose of the general anesthetic as another female of her age and medical history

c. A larger-than-normal dose of the general anesthetic Rationale: Drug tolerance occurs when the body becomes accustomed to a particular drug over time, so that larger doses must be given to produce the same effects. Tolerance may be acquired to the pharmacologic action of many drugs, especially opioid analgesics, alcohol, and other CNS depressants. Tolerance to pharmacologically related drugs is called cross-tolerance. For example, a person who regularly drinks large amounts of alcohol becomes able to ingest even larger amounts before becoming intoxicated; this is tolerance to alcohol. If the person is then given sedative-type drugs or a general anesthetic, larger-than-usual doses are required to produce a pharmacologic effect. This is cross-tolerance.

The nurse is assessing a client who is being admitted to the healthcare facility. When asked about allergies, the client states, "I'm allergic to penicillin." What is the nurse's best initial response? a. "We'll make sure that none of your antibiotics are similar to penicillin." b. "Are there other antibiotics that have worked well for you in the past?" c. "I'll make sure to pass that information along to the pharmacy." d. "Do you remember what happened the last time you received penicillin?"

d. "Do you remember what happened the last time you received penicillin?" Rationale: Any report of an allergy should be documented and communicated clearly. However, the nurse also has a responsibility to gather as much data as possible, especially since clients may classify a wide range of adverse effects as allergies. It would be premature for the nurse to state which antibiotics the client may or may not receive.

A client is receiving 250 mg of a drug that has a half-life of 12 hours. How much drug would remain after 36 hours? a. 125 mg b. 63 mg c. 16 mg d. 31 mg

d. 31 mg Rationale: Half of the drug would be gone in 12 hours, leaving 125 mg. Twelve hours more, or 24 hours total, would leave 62.5 mg. In 36 hours, there would be half of what was available at 24 hours, or 31.25 mg. Twelve hours later, or 48 hours total, there would be 15.625 mg remaining.

The nurse administers a specific medication to an older adult client every 4 hours. The client has a history of chronic renal failure. The nurse should assess for indications of which response? a. Impaired absorption b. Drug-drug interactions c. Drug tolerance d. Cumulative drug effects

d. Cumulative drug effects Rationale: If a drug is taken in successive doses at intervals that are shorter than recommended, or if the body is unable to eliminate a drug properly, the drug can accumulate in the body, leading to toxic levels and adverse effects. This is a cumulative effect. Drug-drug interactions are always a risk, but this risk is not increased by impaired renal function. Renal function has no effect on absorption and it does not increase tolerance.

A patient with an overdose of an oral drug usually receives which of the following? A. specific antidote B. activated charcoal C. syrup of ipecac D. strong laxative

B. activated charcoal Rationale: Activated charcoal is considered the "universal antidote." Most therapeutic drugs do not have specific antidotes; syrup of ipecac to induce vomiting with overdoses of some drugs is no longer recommended (questionable effectiveness, danger of aspiration of vomitus), and strong laxatives are not indicated.

A nurse is reading a research report about use of a medication that describes the pharmacokinetics of a particular medication that a patient is taking. Pharmacokinetics involves A. drug effects on human cells B. drug binding with receptors C. drug absorption, distribution, metabolism, and elimination D. drug stimulation of normal cell functions

C. drug absorption, distribution, metabolism, and elimination Rationale: Pharmacokinetics involves movement of a drug through the body and its elimination. Drug binding with receptors and drug effects on cells are pharmacodynamic processes. Drug stimulation of normal cell functions describes an agonist drug.

A nurse is caring for a man who has worsening liver disease. In monitoring his medication, it is important to know that a patient with liver disease may have impaired drug A. absorption B. distribution C. metabolism D. excretion

C. metabolism Rationale: The liver is mainly involved in drug metabolism. The gastrointestinal tract is mainly involved in absorption of oral drugs, the cardiovascular system is concerned with distribution, and the kidneys are concerned with excretion.

The mother of a 14-month-old girl calls a nurse working in a pediatric clinic and reports that her daughter ingested an unknown number of sleeping pills about 4 hours ago and is now drowsy. The mother asks what she should do. The best response to give the mother is A. "Administer a dose of syrup of ipecac to ensure vomiting" B. "Call the Poison Control Center immediately" C. "Administer a strong laxative and observe for a response" D. "Call 911 to transport your daughter to the nearest emergency department"

D. "Call 911 to transport your daughter to the nearest emergency department" Rationale: The main goals of treatment are starting treatment as soon as possible after drug ingestion, supporting and stabilizing vital functions, preventing further damage from the toxic agent by reducing absorption or increasing elimination, and administering antidotes when available and indicated. Given the time since ingestion and the drowsiness of the girl, this is best accomplished by emergency medical personnel.

A nurse practitioner (NP) has just changed a patient's medication from an oral form to a patch formulation to avoid the first-pass effect. The NP has explained it to the patient, but the patient still has questions and asks the nurse to explain again what is meant by the first-pass effect. The nurse would be most correct in explaining that this has to do with how A. drugs initially bind to plasma proteins B. initial renal function is involved in drug excretion C. the way drugs first reach their target cells D. initial metabolism of an oral drug occurs before it reaches the systemic circulation

D. initial metabolism of an oral drug occurs before it reaches the systemic circulation Rationale: The "first-pass effect" involves metabolism of an oral drug in the liver so that only a portion of a drug dose reaches the systemic circulation and becomes available to act on target tissues or to be eliminated from the body. Drug binding to plasma proteins affects drug distribution; an increased amount of drug has to be absorbed before effective therapeutic levels of unbound drug are reached.

The nurse should consider teratogenic effects when caring for what clients? (Select all that apply.) a. 37-year-old client who is taking fertility drugs b. 29-year-old client receiving prenatal care in her first trimester of pregnancy c. 88-year-old client with chronic heart failure and peripheral edema d. 51-year-old post-menopausal client who is immunocompromised following bone marrow transplant e. 65-year-old client being treated in the intensive care unit for multi-organ dysfunction syndrome

a. 37-year-old client who is taking fertility drugs b. 29-year-old client receiving prenatal care in her first trimester of pregnancy Rationale: A teratogen is a drug that can harm the fetus or embryo so the nurse would consider the teratogenic properties of medications when caring for woman of child-bearing age including adolescents and young adult women. Teratogens have no impact on clients who are not pregnant and who may not become pregnant.

Which client would a nurse expect to experience alterations in drug metabolism? a. 50-year-old man with cirrhosis of the liver b. 62-year-old woman in acute renal failure c. 35-year-old woman with cervical cancer d. 41-year-old man with kidney stones

a. 50-year-old man with cirrhosis of the liver Rationale: The liver is the most important site for drug metabolism. If the liver is not functioning effectively, as with cirrhosis, drugs will not be metabolized normally and toxic levels could develop. Drug dosage will have to be altered to ensure normal levels in the body. The person with kidney stones and the person in acute renal failure would most likely have alterations in drug excretion. If there are no complications with the cervical cancer client, there should be no alterations in drug therapy.

Which client is most likely to experience the benefits of the placebo effect? a. A client who states, "I know this drug is going to work for me." b. A client who states, "I'm not the type of person who likes to take pills." c. A client with pain who says, "I hope this drug works faster than the first one you gave me." d. A client who expresses skepticism about the need for medications.

a. A client who states, "I know this drug is going to work for me." Rationale: A drug is more likely to be effective if the client thinks it will work than not work. This is called the placebo effect, as reflected in the statement about the drug curing the infection. Doubt about the effectiveness of a drug or preference for avoiding medication treatment would not demonstrate the placebo effect.

The nurse is assessing a client who has developed shortness of breath, a rash, panic and a blood pressure of 189/106 mm Hg after being administered a new medication. In addition to promptly informing the care team, the nurse should perform what action? a. Administering epinephrine as prescribed b. Providing supplementary oxygen by nasal cannula c. Performing cardiopulmonary resuscitation d. Administering monoclonal antibodies as prescribed

a. Administering epinephrine as prescribed Rationale: This client is likely experiencing anaphylaxis and requires epinephrine. There is no indication that CPR is needed. Supplementary oxygen is likely needed, but nasal cannula would likely be insufficient. Monoclonal antibodies are not used to treat anaphylaxis.

A client develops a skin reaction to one of their prescribed medications. This client also has a specific underlying pathology. This underlying pathology might serve as a: a. Contraindication for the use of certain medications. b. Basis for the nursing care plan. c. Prominent part of client teaching. d. Basis for planning the medication regimen.

a. Contraindication for the use of certain medications. Rationale: The possibility that the adverse effects can occur also accounts for the contraindications for the use of some drugs in clients with a particular history or underlying pathology. The acute problem would serve as a basis for planning the client's medication regimen and the nursing care plan. The acute problem would also be the most prominent part of client teaching.

A client is taking low-dose aspirin daily for her heart. The client is not receiving all the dosage of the aspirin that is being ingested because of: a. First-pass effect. b. Biotransformation. c. Liver metabolism. d. Portal circulation.

a. First-pass effect. Rationale: A large percentage of an oral dose is destroyed when it reaches the liver and never reaches the tissues. This phenomenon is known as the first-pass effect.

A nurse has identified the half-life of drug that will be administered to a client for the first time. The nursing drug guide states the drug's half-life is 90 minutes. The nurse should identify what implication of this fact? a. Ninety minutes after drug levels peak, there will be 50% of the peak level. b. In 3 hours, there will be no detectable levels of the drug presents in the client's body. c. Drug levels will rise steadily after administration, reaching 50% of maximum concentration after 90 minutes. d. Peak drug levels will be achieved 90 minutes after the drug is administered.

a. Ninety minutes after drug levels peak, there will be 50% of the peak level. Rationale: The half-life of a drug is the time it takes for the amount of drug in the body to decrease to half the peak level it previously achieved. In this case, 50% of peak levels will be achieved 90 minutes after the peak.

The nurse is assessing a client whose debilitating headache did not respond to the recommended dose of an OTC analgesic. In response, the client took another dose 30 minutes later and then a double dose one hour after that. The nurse's assessment should focus on the possibility of: a. Poisoning. b. Allergies. c. Hypersensitivity. d. Anaphylaxis.

a. Poisoning. Rationale: Poisoning occurs when an overdose of a drug damages multiple body systems, leading to the potential for fatal reactions. Hypersensitivity, allergies, and anaphylaxis would not be indicated by an overdosage of the medication.

Toxic concentrations may stem from a single large dose or repeated small doses. a. TRUE b. FALSE

a. TRUE

The nurse should have basic knowledge of drug classifications in order to administer medications safely to clients. What drug information is instrumental in determining nursing actions following drug administration? a. Route of administration b. Adverse effects c. Protocols d. Body system affected

b. Adverse effects Rationale: Becoming familiar with classifications of medications helps the nurse to recognize possible adverse effects clients may experience, providing a basis for implementing appropriate nursing actions should undesirable effects occur. The route of administration, body system involved, and protocols are more important to know before medication administration.

A client has not experienced the desired therapeutic effects of a medication. When considering factors that may affect the dynamic equilibrium that influences drug concentration, the nurse should: a. Assess the client for adverse effects. b. Assess for factors that may reduce absorption. c. Educate the client about drug-drug interactions. d. Review the client's electrolyte levels.

b. Assess for factors that may reduce absorption. Rationale: Reduced absorption is among that factors that contribute to the dynamic equilibrium affecting drug concentration. Electrolyte levels do not have a major effect on this dynamic equilibrium. It is important to assess for interactions and adverse effects, but these do not affect the dynamic equilibrium or concentration.

A client has developed a tolerance to a drug. How should the nurse address this when providing care? a. Assess the client for signs and symptoms of an allergy to the drug. b. Assess whether the client needs larger doses to achieve the effect. c. Assess the client for signs and symptoms of adverse drug effects. d. Advocate for a change in the client's medication.

b. Assess whether the client needs larger doses to achieve the effect. Rationale: With tolerance, increasingly larger doses are needed to achieve the therapeutic effect. An allergy would be manifested by reactions ranging from mild, such as a rash, to more severe, such as anaphylaxis. Although a change may be needed, tolerance typically requires an increase in dosage. To avoid the need for continually larger doses, other drugs may be added to regimen to achieve the effect. Tolerance is unrelated to adverse effects.

What would the nurse include in the teaching plan for a client who is to receive a drug that is associated with anticholinergic effects? a. Eat a low-fiber diet to prevent constipation. b. Be sure to drink plenty of fluids to prevent dehydration. c. Try to stay as warm as possible to prevent chilling. d. Avoid strenuous exercise to minimize calorie loss

b. Be sure to drink plenty of fluids to prevent dehydration. Rationale: Drugs with anticholinergic effects often cause dry mouth, constipation, dehydration, and decreased sweating. The client should be instructed to drink fluids to prevent dehydration and to avoid overly warm or hot environments. Avoiding exercise to affect calorie intake is not necessary. A high-fiber diet would be indicated to prevent constipation.

A client in distress is brought to the emergency department by ambulance. Emergency medical technicians state that an anaphylactic reaction from oral penicillin is suspected. Which of the nurse's assessment findings best supports this diagnosis? a. Hematocrit (Hct): 32%, decreased urine output b. Blood pressure: 186/100 mm Hg, shortness of breath c. Profuse sweating, oxygen saturation: 92% d. Temperature: 102º F (38.9º C), swollen joints

b. Blood pressure: 186/100 mm Hg, shortness of breath Rationale: An anaphylactic reaction is an immune reaction that causes a massive release of histamine, which results in edema and swelling that can lead to respiratory distress and increased blood pressure. A decreased hematocrit and decreased urine output suggests a cytotoxic reaction. An increased temperature and swollen joints could suggest serum sickness. Oxygen saturation levels would be decreased due to respiratory distress.

A client is four months' pregnant. She works in the chemical unit of a research department and is responsible for handling various chemicals. Her gynecologist advised her not to expose herself to chemical or industrial vapors and specific drugs. These restrictions are advised because exposure to industrial vapors could: a. Affect the liver of the fetus. b. Damage the immature nervous system of the fetus. c. Affect the eighth cranial nerve of the fetus. d. Affect the kidneys of the fetus.

b. Damage the immature nervous system of the fetus. Rationale: Neurotoxicity can occur as a result of exposure to drugs and other chemicals and gases, such as industrial vapors. Immature nervous systems such as those of the fetus and neonate can easily be damaged by drugs that produce neurotoxicity. Hence, the client has been advised not to expose herself to chemical or industrial vapors and specific drugs. The liver and kidney functions and the eighth cranial nerve of the fetus are not directly affected as a result of exposure to neurotoxic substances.

When researching information about a drug, the nurse finds that the drug tightly binds to protein. The nurse would interpret this to mean that the drug will: a. Be excreted quickly. b. Have a long duration of action. c. Lead to toxicity when given. d. Be released fairly quickly.

b. Have a long duration of action. Rationale: Drugs that are tightly bound to protein are released very slowly and have a very long duration of action because they are not free to be broken down or excreted. Drugs that are loosely bound tend to act quickly and to be excreted quickly. Drugs that compete with each other for protein binding sites alter the effectiveness or cause toxicity when the two drugs are given together.

A nurse is planning client teaching about a newly prescribed drug. What teaching point should the nurse provide to best improve adherence and safety? a. List of pharmacies where the drug can be obtained b. Measures to alleviate any discomfort associated with adverse effects c. Statistics related to phase III testing for the prescribed drug d. The benefits of the prescribed drug over alternatives from the same class

b. Measures to alleviate any discomfort associated with adverse effects Rationale: If a client is aware of certain adverse effects and how to alleviate or decrease the discomfort, he or she is more likely to continue taking the medication. A list of pharmacies can be useful information but will not improve safety or compliance. Knowing the relative benefits of the drug over alternatives may enhance adherence but has no effect on safety. Most clients are not concerned with the statistics related to drug testing and it would not improve adherence or safety even if the client was interested in the information.

The nurse is caring for a client who is receiving gentamicin, 250 mg, and fluconazole, 500 mg, at the same time. What effect should the nurse anticipate if these two drugs competed with each other for protein-binding sites? a. Gentamicin will be metabolized faster than usual. b. The effectiveness of both drugs will be altered. c. Risks of adverse drug effects will increase. d. Potential positive benefits of each drug will cancel each other out.

b. The effectiveness of both drugs will be altered. Rationale: Some drugs compete with each other for protein-binding sites, altering effectiveness or causing toxicity when the two drugs are given together. Metabolism will not be increased, and this does not mean the drugs' effects cancel each other out. Similarly, competition for binding sites does not result in an increased risk of adverse effects.

An elderly client has been taking a new medication for 2 months. During a follow-up visit, the client's son tells the nurse that he feels his mother's memory is getting worse. What concerns should the nurse have at this time? a. All elderly clients have dementia at some point in life, and the medication is making it worse. b. This may be coincidental, and the memory loss may be attributed to changes with aging. c. The client probably has the onset of Alzheimer disease. d. The nurse should not be concerned. Medication is not the cause of the client's confusion.

b. This may be coincidental, and the memory loss may be attributed to changes with aging. Rationale: It is important for nurses and other health care professionals to be alert for adverse effects from drug therapy. Sometimes, determining whether an adverse effect has occurred as a result of drug therapy is difficult. Adverse effects may be mistaken for changes associated with aging or disease pathology.

What changes due to aging in the geriatric client may affect excretion and promote accumulation of drugs in the body? a. Decreased gastric motility. b. Decreased cognition. c. Decreased glomerular filtration rate. d. Decreased activity.

c. Decreased glomerular filtration rate. Rationale: In older adults (65 years and older), physiologic changes may alter all pharmacokinetic processes. Changes in the gastrointestinal tract include decreased gastric acidity, decreased blood flow, and decreased motility. Despite these changes, however, there is little difference in drug absorption. Changes in the cardiovascular system include decreased cardiac output, and therefore slower distribution of drug molecules to their sites of action, metabolism, and excretion. In the liver, blood flow and metabolizing enzymes are decreased. Therefore, many drugs are metabolized more slowly, have a longer action, and are more likely to accumulate with chronic administration. In the kidneys, there is decreased blood flow, decreased glomerular filtration rate, and decreased tubular secretion of drugs; all of these changes tend to slow excretion and promote accumulation of drugs in the body. Impaired kidney and liver function greatly increases the risks of adverse drug effects. In addition, older adults are more likely to have acute and chronic illnesses that require the use of multiple drugs or long-term drug therapy. Therefore, possibilities for interactions among drugs and between drugs and diseased organs are greatly multiplied.

The processes involved in dynamic equilibrium are key elements in the nurse's ability to determine what? a. Amount of solution for mixing parental drugs b. How long the client has to take the drug c. Dosage scheduling d. Timing of other drugs the client is taking

c. Dosage scheduling Rationale: These processes are key elements in determining the amount of drug (dose) and the frequency of dose repetition (scheduling) required to achieve the critical concentration for the desired length of time. The processes in dynamic equilibrium are not key elements in determining the amount of diluents for intramuscular (IM) drugs; they do not aid in the timing of the other drugs the client is taking or how long the client has to take the drug.

The nurse's discussion of the role of cytochrome P-450 (CYP) enzymes is focusing on what aspect of pharmacokinetics? a. Drug transported through the cells of the GI tract b. Elimination of drug proteins through the process of denaturing c. Drug metabolism that takes place in the liver d. The role of the kidneys in pharmacokinetics

c. Drug metabolism that takes place in the liver Rationale: Most drugs are metabolized by cytochrome P-450 (CYP) enzymes in the liver. The CYP system consists of several groups of enzymes, some of which metabolize endogenous substances and some of which metabolize drugs. The CYP system does not participate in elimination, as in denaturing or the role of the kidneys, or drug transport via the GI tract.

Whereas some drugs or metabolites are excreted in bile and then eliminated in feces, others are excreted in bile, reabsorbed from the small intestine, and then returned to the liver. What is the name of this process? a. First-pass effect b. Enterorenal recirculation c. Enterohepatic recirculation d. Pharmacodynamics

c. Enterohepatic recirculation Rationale: Some drugs or metabolites are excreted in bile and then eliminated in feces; others are excreted in bile, reabsorbed from the small intestine, and then returned to the liver in a process called enterohepatic recirculation. The first-pass effect involves drug metabolism, which takes place prior to excretion. Pharmacodynamics is the broad term used to describe drug action are target cells and the resulting cellular biochemical reactions.

What drug administration route should be used to assure the best bioavailability as any particular drug? a. Intramuscular b. Oral c. Intravenous d. Subcutaneous

c. Intravenous Rationale: Bioavailability refers to the portion of a dose that reaches the systemic circulation and is available to act on body cells. Drugs given via the oral, IM, and Sub-Q routes are virtually always less than 100% available because some of the drug is absorbed in the GI or liver before reaching systemic circulation. An intravenous (IV) drug is virtually 100% bioavailable. In contrast, an oral drug is virtually always less than 100% bioavailable because some of it is not absorbed from the GI tract and some goes to the liver and is partially metabolized before reaching the systemic circulation.

A newly admitting client has signs and symptoms of an infection and the nurse anticipates that the client will be prescribed antibiotics. What assessment should the nurse prioritize when determining the client's risk for an excessive drug response due to impaired excretion? a. The client's body mass index and hydration status b. The client's fasting blood glucose level c. The client's blood urea nitrogen level and creatinine clearance rate d. The client's albumin, bilirubin, AST and ALT levels

c. The client's blood urea nitrogen level and creatinine clearance rate Rationale: Renal impairment creates a risk for excessive drug responses due to delayed, or absent, excretion. This variable will likely have a greater bearing than the client's BMI, hydration status and blood glucose, though these may have an effect on pharmacokinetics. The client's hepatic status would primarily affect metabolism, not excretion.

Why does the nurse need to be alert for any indication of an allergic reaction in clients? a. To obtain early warning of noncompliance in drug therapy b. To reduce the risk of adverse effects during drug therapy c. To maintain the client's safety during drug therapy d. To increase the effectiveness of a specific medication

c. To maintain the client's safety during drug therapy Rationale: Being alert to adverse effects—what to assess and how to intervene appropriately—can increase the effectiveness of a drug regimen, provide for client safety, and improve client compliance. Indications of allergic reactions would not indicate noncompliance or improve effectiveness of a specific medication. Indications of allergic reaction would indicate an adverse effect and would not reduce the risk.

A client states, "A few years I could drink 4-5 beers and felt great, but now I need to drink 12 beers to feel great." What is this an example of what type of alcohol-related behavior? a. Physical dependence b. Low self-esteem c. Tolerance d. Withdrawal

c. Tolerance Rationale: The client is describing tolerance. Tolerance is the need for increasingly larger or more frequent doses of a substance to obtain the desired effects originally produced by a lower dose. Withdrawal is development of a substance-specific maladaptive behavioral change, with physiological and cognitive symptoms concomitant due to the cessation of or reduction in heavy and prolonged substance use. Physical dependence is a cluster of cognitive, behavioral, and physiological symptoms, indicating a person continues to use a substance of abuse despite significant substance-related problems. The person may have low self-esteem but the example is not of low self-esteem.

The nurse is caring for a client receiving an aminoglycoside (antibiotic) that can be nephrotoxic. Which will alert the nurse that the client may be experiencing nephrotoxicity? a. Visual disturbances b. Ringing noise in the ears c. Yellowing of the skin d. A decrease in urine output

d. A decrease in urine output Rationale: The client is describing tolerance. Tolerance is the need for increasingly larger or more frequent doses of a substance to obtain the desired effects originally produced by a lower dose. Withdrawal is development of a substance-specific maladaptive behavioral change, with physiological and cognitive symptoms concomitant due to the cessation of or reduction in heavy and prolonged substance use. Physical dependence is a cluster of cognitive, behavioral, and physiological symptoms, indicating a person continues to use a substance of abuse despite significant substance-related problems. The person may have low self-esteem but the example is not of low self-esteem.

A nurse is preparing to administer a prescribed drug to a client who has liver disease. The nurse expects a reduction in dosage based on the understanding that what might be altered? a. Distribution b. Absorption c. Excretion d. Metabolism

d. Metabolism Rationale: The liver is the single most important site of drug metabolism. If it is not functioning properly, the drug may not be metabolized correctly and may reach toxic levels in the body. Liver disease does not affect absorption or distribution. Kidney disease would affect drug excretion.

A client prescribed a drug that has an exceptionally narrow margin of safety should be educated about the need for what intervention? a. Frequent administration of scheduled "drug holidays" b. Half-life analysis c. Regular changes to the administration route d. Serum drug level monitoring

d. Serum drug level monitoring Rationale: Measuring serum drug levels is useful when drugs with a narrow margin of safety are given because their therapeutic doses are close to their toxic doses. None of the other options are relevant to client safety regarding this drug characteristic.

How is pharmacodynamics best defined? a. The method by which a drug is distributed through the body b. The time that elapses between absorption and excretion of a drug c. The way that the liver or kidneys alter the chemical structure of a drug d. The action that the drug has on body cells

d. The action that the drug has on body cells Rationale: Pharmacodynamics involves drug actions on target cells and the resulting alterations in cellular biochemical reactions and functions. Distribution, excretion, and metabolism are all aspects of pharmacokinetics.

An experienced nurse has observed that female clients sometimes experience a drug's effects for a longer time than male clients of similar age and size. The nurse should attribute this to what factor? a. Men commonly lack certain enzyme systems that are necessary for metabolizing a drug. b. Women more often experience electrolyte imbalances, prolonging a drug's effect. c. Men have more vascular muscle so drug effects will take longer to occur. d. Women have more fat cells so drugs depositing in fat will have a prolonged effect.

d. Women have more fat cells so drugs depositing in fat will have a prolonged effect. Rationale: Women have more fat cells, so drugs that deposit in fat may be slowly released and cause effects for a longer period of time. Men have more vascular muscles than women do. As a result, drugs administered to men via the IM route reach a peak level faster than they do in women. Electrolyte imbalances can affect the way a drug works on the body, however, women are not at a greater risk for electrolyte imbalances. Genetic differences, not gender, may result in either a lack of certain enzyme differences or overactivity of enzyme systems, resulting in varied responses to a drug.

Body weight affects drug action mainly in relation to __________.

dose