1.
Pindolol and some other β adrenergic receptor antagonists have an additional property that is referred to as intrinsic sympathomimetic activity (ISA). This additional property indicates these agents are:
Correct Answer
E. Partial agonists
Explanation
Pindolol and some other β adrenergic receptor antagonists have intrinsic sympathomimetic activity (ISA), which means that they can partially activate the β adrenergic receptors. Unlike full agonists, which fully activate the receptors, and neutral antagonists, which have no effect on the receptors, partial agonists have a moderate level of activation. Therefore, Pindolol and other β adrenergic receptor antagonists with ISA can partially activate the receptors while still blocking the effects of other agonists.
2.
A 28-year-old woman is brought to the emergency department after overdosing on oxycodone, an opiate analgesic. She is unconscious and barely breathing when she arrives at the hospital, but revives and is breathing normally within 2 minutes after receiving an injection of naloxone. After about an hour, she requires another dose of naloxone as the symptoms of opiate overdose begin to redevelop. Naloxone is likely acting as a:
Correct Answer
D. Competitive antagonist of opioid receptors.
Explanation
Naloxone is a competitive antagonist of opioid receptors. Opioid receptors are the targets of opioids like oxycodone, and naloxone competes with these opioids for binding to the receptors. By binding to the receptors, naloxone blocks the effects of the opioids, reversing their depressant effects on the central nervous system. This explains why the woman revives and begins breathing normally after receiving naloxone. However, since naloxone has a shorter half-life than oxycodone, the symptoms of opiate overdose start to redevelop after some time, requiring another dose of naloxone.
3.
The therapeutic window is an indication of the:
Correct Answer
D. Range of concentrations over which a drug is safe and efficacious for most patients
Explanation
The therapeutic window refers to the range of concentrations at which a drug is both safe and effective for most patients. This means that the drug is within the desired therapeutic range, where it can produce the desired therapeutic effects without causing significant adverse effects. It is important to monitor drug concentrations within this window to ensure optimal treatment outcomes.
4.
Preclinical characterization of a new drug indicates that it is an inverse agonist for adenosine receptors. It interacts syntopically with adenosine. In the presence of adenosine, this drug will behave like a(n):
Correct Answer
E. Competitive antagonist with inhibitory effects on receptor activation
Explanation
Based on the information provided, the drug is described as an inverse agonist for adenosine receptors, meaning it has an opposite effect to adenosine. Therefore, in the presence of adenosine, the drug will act as a competitive antagonist, inhibiting the activation of the receptor. This indicates that the drug will have inhibitory effects on receptor activation, making the correct answer "competitive antagonist with inhibitory effects on receptor activation."
5.
The term “first-pass effect” refers to the
Correct Answer
C. Ability of the intestines and liver to reduce the bioavailability of a drug.
Explanation
The term "first-pass effect" refers to the ability of the intestines and liver to reduce the bioavailability of a drug. This means that after oral administration of a drug, the drug may undergo metabolism and elimination in the intestines and liver before it can reach systemic circulation and exert its therapeutic effects. This can result in a lower concentration of the drug reaching the target tissues, reducing its effectiveness.
6.
The term “blood-brain barrier” (BBB) refers to a:
Correct Answer
B. Cellular barrier that includes brain capillary endothelial cells that limits drug entry into the brain.
Explanation
The term "blood-brain barrier" refers to a cellular barrier that includes brain capillary endothelial cells that limits drug entry into the brain. This barrier is formed by tight junctions between the endothelial cells of the brain capillaries, which prevents the free diffusion of drugs and other substances from the blood into the brain. Only certain molecules that are transported by specific carriers can cross this barrier and enter the central nervous system.
7.
Phase 1 drug metabolism differs from phase 2 metabolism in that:
Correct Answer
E. pHase 1 metabolic reactions functionalize drugs, whereas pHase 2 metabolic reactions conjugate drugs.
Explanation
Phase 1 drug metabolism and phase 2 drug metabolism are two distinct processes. Phase 1 metabolic reactions involve the functionalization of drugs, which can include processes such as oxidation, reduction, and hydrolysis. These reactions often result in the formation of more polar and water-soluble metabolites. In contrast, phase 2 metabolic reactions involve the conjugation of drugs with endogenous compounds, such as glucuronic acid, sulfate, or amino acids. This conjugation process further increases the water solubility of the drugs, facilitating their elimination from the body through urine or bile. Therefore, phase 1 metabolism functionalizes drugs, while phase 2 metabolism conjugates drugs.
8.
The most important pharmacokinetic concept to consider when designing a rational long-term pharmacotherapy is
Correct Answer
D. Clearance.
Explanation
Clearance is the most important pharmacokinetic concept to consider when designing a rational long-term pharmacotherapy because it determines the rate at which a drug is removed from the body. Clearance is the volume of plasma cleared of the drug per unit of time, and it is influenced by factors such as liver and kidney function. Understanding clearance is crucial in determining the appropriate dosage and dosing interval to maintain therapeutic drug levels over an extended period of time.
9.
A drug that is a weak acid (pKa = 5) is largely excreted unchanged by the kidneys. To increase its rate of excretion
Correct Answer
A. The pH of the urine should be increased.
Explanation
To increase the rate of excretion of a weak acid drug, the pH of the urine should be increased. This is because weak acids are more ionized in alkaline conditions. When the pH of the urine is increased, the weak acid drug will become more ionized, making it less likely to be reabsorbed by the renal tubules and more likely to be excreted in the urine. Therefore, increasing the pH of the urine will enhance the elimination of the drug from the body.
10.
A 3-year-old is brought to the emergency department having just ingested a large overdose of tolbutamide, an oral antidiabetic drug. Tolbutamide is a weak acid with a pKa of 5.3. It is capable of entering most tissues, including the brain. On physical examination, the heart rate is 100/min, blood pressure 90/50 mm Hg, and respiratory rate 20/min. Which of the following statements about this case of tolbutamide overdose is most correct?
Correct Answer
B. Urinary excretion would be accelerated by giving NaHCO3, an alkalinizing agent
Explanation
Tolbutamide is a weak acid, and weak acids are more likely to be excreted in the urine when the urine is alkaline. By giving NaHCO3, an alkalinizing agent, the pH of the urine will increase, promoting the excretion of the drug. This is the most correct statement because it aligns with the pharmacokinetics of weak acids. The other options are not correct because NH4Cl would acidify the urine, which would decrease excretion, less of the drug would be ionized at blood pH than at stomach pH, and the absorption of the drug would not be affected by the pH of the stomach or small intestine. Hemodialysis may be considered in severe cases, but it is not the only effective therapy.
11.
Botulinum toxin is a large protein molecule. Its action on cholinergic transmission depends on an intracellular action within nerve endings. Which one of the following processes is best suited for permeation of very large protein molecules into cells?
Correct Answer
B. Endocytosis
Explanation
Endocytosis is the process by which cells engulf large molecules or particles by forming a vesicle around them and bringing them into the cell. This process is best suited for the permeation of very large protein molecules into cells because it allows the protein to be enclosed within a vesicle and transported across the cell membrane. Aqueous diffusion, lipid diffusion, and special carrier transport are not suitable for large protein molecules, as they are primarily used for smaller molecules. The first-pass effect refers to the metabolism of drugs in the liver before they reach the systemic circulation and is not relevant to the permeation of protein molecules into cells.
12.
A 12-year-old child has bacterial pharyngitis and is to receive an oral antibiotic. She complains of a sore throat and pain on swallowing. The tympanic membranes are slightly reddened bilaterally, but she does not complain of earache. Blood pressure is 105/70 mm Hg, heart rate 100/mm, temperature 37.8 °C (100.1 °F). Ampicillin is a weak organic acid with a pKa of 2.5. What percentage of a given dose will be in the lipid-soluble form in the duodenum at a pH of 4.5?
Correct Answer
A. About 1%
13.
Ampicillin is eliminated by first-order kinetics. Which of the following statements best describes the process by which the plasma concentration of this drug declines?
Correct Answer
B. The half-life is the same regardless of the plasma concentration
Explanation
The half-life of a drug refers to the time it takes for the concentration of the drug in the plasma to decrease by half. In this case, the statement that the half-life is the same regardless of the plasma concentration suggests that the rate of elimination of Ampicillin remains constant over time. This indicates that Ampicillin follows first-order kinetics, where the rate of elimination is proportional to the drug concentration. Therefore, as the drug concentration decreases, the rate of elimination also decreases, resulting in a consistent half-life.
14.
The pharmacokinetic process or property that distinguishes the elimination of ethanol and high doses of phenytoin and aspirin from the elimination of most other drugs is called
Correct Answer
E. Zero-order elimination
Explanation
Zero-order elimination is the pharmacokinetic process or property that distinguishes the elimination of ethanol and high doses of phenytoin and aspirin from the elimination of most other drugs. In zero-order elimination, the rate of elimination remains constant regardless of the concentration of the drug in the body. This is different from first-order elimination, where the rate of elimination is proportional to the drug concentration. Zero-order elimination is typically seen when the elimination pathways for the drug become saturated at higher doses, resulting in a constant rate of elimination.
15.
A new drug was administered intravenously, and its plasma levels were measured for several hours. A graph was prepared as shown below, with the plasma levels plotted on a logarithmic ordinate and time on a linear abscissa.
It was concluded that the drug has first-order kinetics. From this graph, what is the best estimate of the half-life?
Correct Answer
C. 3h
Explanation
The best estimate of the half-life can be determined by finding the time it takes for the plasma levels to decrease by half. In the given graph, it can be observed that the plasma levels decrease by half at around 3 hours. Therefore, the best estimate of the half-life is 3 hours.
16.
A large pharmaceutical company has conducted extensive animal testing of a new drug for the treatment of advanced prostate cancer. The chief of research and development recommends that the company now submit an IND application in order to start clinical trials. Which of the following statements is most correct regarding clinical trials of new drugs?
Correct Answer
A. pHase 1 involves the study of a small number of normal volunteers by highly trained clinical pHarmacologists
Explanation
Phase 1 of clinical trials involves studying a small number of normal volunteers under the supervision of highly trained clinical pharmacologists. This phase is focused on assessing the safety and dosage of the new drug in humans. It helps determine the drug's pharmacokinetics, pharmacodynamics, and potential side effects. The goal is to gather preliminary data on the drug's safety profile and establish a safe dosage range for further testing. This phase is crucial in determining whether the drug can progress to the next phases of clinical trials.
17.
Which of the following statements about the testing of new compounds for potential therapeutic use in the treatment of hypertension is most correct?
Correct Answer
B. Human studies in normal individuals will be done before the drug is used in individuals with hypertension
Explanation
Before a new compound is used in individuals with hypertension, human studies in normal individuals will be conducted. This is because it is important to first understand the safety and effectiveness of the compound in a controlled setting before testing it on individuals with the specific condition. By conducting studies in normal individuals, researchers can gather valuable information about the compound's potential therapeutic use and any potential risks or side effects. This helps to ensure the safety and efficacy of the compound before it is used in individuals with hypertension.
18.
Which of the following statements about new drug development is most correct?
Correct Answer
A. Drugs that test positive for teratogenicity, mutagenicity, or carcinogenicity can be tested in humans
19.
A 55-year-old woman with hypertension is to be treated with a thiazide diuretic. Thiazide A in a dose of 5 mg produces the same decrease in blood pressure as 500 mg of thiazide B. Which of the following statements best describes these results?
Correct Answer
B. Thiazide A is about 100 times more potent than thiazide B
Explanation
The statement "Thiazide A is about 100 times more potent than thiazide B" best describes the results because it indicates that a much lower dose of Thiazide A (5 mg) produces the same decrease in blood pressure as a higher dose of Thiazide B (500 mg). This suggests that Thiazide A is more effective and has a greater potency than Thiazide B.
20.
Prior to clinical trials in patients with heart failure, an animal study was carried out to compare two new positive inotropic drugs (A and B) to a current standard agent (C). The results of cardiac output measurements are shown in the graph below.
Which of the following statements is correct?
Correct Answer
D. Drug B is more potent than drug C and more effective than drug A
Explanation
Based on the graph, the cardiac output for drug B is higher than drug C, indicating that drug B is more potent than drug C. Additionally, the cardiac output for drug A is lower than both drug B and drug C, suggesting that drug B is more effective than drug A. Therefore, the correct statement is "Drug B is more potent than drug C and more effective than drug A."
21.
A study was carried out in isolated intestinal smooth muscle preparations to determine the action of a new drug “novamine,” which in separate studies bound to the same receptors as acetylcholine. In the absence of other drugs, acetylcholine caused contraction of the muscle. Novamine alone caused relaxation of the preparation. In the presence of a low concentration of novamine, the EC50 of acetylcholine was unchanged, but the Emax was reduced. In the presence of a high concentration of novamine, extremely high concentrations of acetylcholine had no effect. Which of the following expressions best describes novamine?
Correct Answer
B. An irreversible antagonist
Explanation
Novamine is best described as an irreversible antagonist because it binds to the same receptors as acetylcholine and causes relaxation of the smooth muscle. In the presence of a low concentration of novamine, the effectiveness of acetylcholine is reduced (Emax is reduced), and in the presence of a high concentration of novamine, acetylcholine has no effect. This suggests that novamine irreversibly blocks the receptors, preventing acetylcholine from causing muscle contraction.
22.
Sugammadex is a new drug that reverses the action of rocuronium and certain other skeletal muscle-relaxing agents (nondepolarizing neuromuscular blocking agents). It appears to interact directly with the rocuronium molecule and not at all with the rocuronium receptor. Which of the following terms best describes sugammadex?
Correct Answer
A. Chemical antagonist
Explanation
Sugammadex is classified as a chemical antagonist because it directly interacts with the rocuronium molecule to reverse its action. It does not bind to the rocuronium receptor, making it different from a competitive or noncompetitive antagonist. It also does not have any agonistic activity, ruling out partial agonist. Sugammadex is a specific drug that acts chemically to counteract the effects of rocuronium, making it a chemical antagonist.
23.
A 42-year-old man has just been prescribed a new drug. After several doses he notices dry mouth, dry eyes, and a rapid heart rate. This is most likely due to an inhibition of which of the following neurotransmitter:
Correct Answer
D. Acetylcholine
Explanation
The symptoms of dry mouth, dry eyes, and rapid heart rate are consistent with the side effects of anticholinergic drugs. Acetylcholine is a neurotransmitter that is involved in the regulation of various bodily functions including salivation, tear production, and heart rate. Inhibition of acetylcholine can lead to decreased production of saliva and tears, as well as an increased heart rate. Therefore, the most likely explanation for the symptoms experienced by the man is an inhibition of acetylcholine.
24.
A 23-year-old man is accosted by 3 men late at night. Immediately his heart rate increases due to an increase in epinephrine in his circulation. This release of epinephrine from the adrenal medulla is the result of the action of acetylcholine on
Correct Answer
C. Nicotinic receptors.
Explanation
Acetylcholine is the neurotransmitter responsible for activating nicotinic receptors in the adrenal medulla. When acetylcholine binds to nicotinic receptors, it triggers the release of epinephrine from the adrenal medulla, leading to an increase in heart rate. Therefore, the correct answer is nicotinic receptors.
25.
A 56-year-old woman goes to an ophthalmologist for an eye examination. The ophthalmologist administers an eye drop to dilate her pupils prior to the eye examination. The medication in the eye drop is most likely acting on
Correct Answer
B. &alpHa;1 adrenergic receptors.
Explanation
The medication in the eye drop is most likely acting on α1 adrenergic receptors. This is because α1 adrenergic receptors are responsible for pupil dilation. When these receptors are stimulated, the muscles in the iris contract, causing the pupil to dilate. Therefore, the medication in the eye drop is likely targeting these receptors to achieve pupil dilation for the eye examination.
26.
The neurotransmitter at the neuromuscular junction is
Correct Answer
A. Acetylcholine.
Explanation
Acetylcholine is the correct answer because it is the primary neurotransmitter responsible for transmitting signals from motor neurons to muscle fibers at the neuromuscular junction. It is released by the motor neuron and binds to receptors on the muscle fiber, leading to muscle contraction. Norepinephrine, serotonin, aspartate, and epinephrine are all neurotransmitters involved in other functions within the nervous system, but they are not specifically associated with the neuromuscular junction.
27.
A 33-year-old woman with a brain infection (meningitis) is administered her antibiotic directly into the cerebrospinal fluid because the
Correct Answer
B. Blood brain barrier excludes the antibiotic if it is administered systemically.
Explanation
The correct answer is that the blood brain barrier excludes the antibiotic if it is administered systemically. The blood brain barrier is a protective barrier that separates the circulating blood from the brain and spinal cord. It is composed of specialized cells that tightly regulate what substances can pass through into the brain. Many antibiotics are unable to cross this barrier when administered systemically, which can limit their effectiveness in treating brain infections. Therefore, administering the antibiotic directly into the cerebrospinal fluid bypasses the blood brain barrier and allows for direct delivery to the site of infection.
28.
An 80-year-old woman is administered a CNS depressant drug for anxiety. When she abruptly stops the drug, after taking it for many years, she is likely to experience
Correct Answer
B. Hyperexcitability.
Explanation
When the 80-year-old woman abruptly stops taking the CNS depressant drug for anxiety, she is likely to experience hyperexcitability. This is because long-term use of CNS depressants can lead to tolerance and dependence. Abruptly stopping the drug can cause withdrawal symptoms, and in this case, hyperexcitability is a common withdrawal symptom. This means that the woman may experience increased agitation, restlessness, and heightened sensitivity to stimuli.
29.
A 35-year-old man has ingested Amanita muscaria mushrooms. He is experiencing a heart rate of 40 beats per minute. This bradycardia is most likely due to an interaction of the chemical(s) in the mushrooms with which receptors at the sinoatrial node?
Correct Answer
D. M2 muscarinic
Explanation
The bradycardia observed in the 35-year-old man who ingested Amanita muscaria mushrooms is most likely due to an interaction of the chemical(s) in the mushrooms with M2 muscarinic receptors at the sinoatrial node. M2 muscarinic receptors are found in the heart and their activation leads to a decrease in heart rate.
30.
A 49-year-old woman is treated with pilocarpine hydrochloride for xerostomia (dry mouth) following head and neck radiation treatments. As a result of taking this drug she may experience which of the following side effects?
Correct Answer
A. Sweating
Explanation
Pilocarpine hydrochloride is a medication that stimulates the sweat glands, leading to increased sweating. Therefore, it is expected that a 49-year-old woman who is being treated with this drug for xerostomia may experience sweating as a side effect.
31.
A 54-year-old woman is receiving Botox injections to remove facial wrinkles. Botox (botulinum toxin) acts by
Correct Answer
C. Blocking the release of ACh.
Explanation
Botox (botulinum toxin) is known to block the release of acetylcholine (ACh). Acetylcholine is a neurotransmitter that plays a role in muscle contraction. By blocking its release, Botox inhibits the communication between nerves and muscles, resulting in temporary muscle paralysis. This paralysis helps to reduce the appearance of facial wrinkles by preventing the repetitive muscle contractions that contribute to their formation.
32.
A 23-year-old man has deliberately ingested an organophosphate insecticide. His initial symptoms of salivation, lacrimation, and diarrhea are a consequence of inhibition of
Correct Answer
B. Acetylcholinesterase.
Explanation
The initial symptoms of salivation, lacrimation, and diarrhea are consistent with the effects of increased acetylcholine activity. Organophosphate insecticides inhibit acetylcholinesterase, the enzyme responsible for breaking down acetylcholine. This inhibition leads to an accumulation of acetylcholine in the body, causing excessive stimulation of cholinergic receptors and resulting in symptoms such as increased salivation, tearing, and gastrointestinal disturbances. Therefore, the correct answer is acetylcholinesterase.
33.
The patient in Question 10 should be treated with atropine and which additional drug in the following list?
Correct Answer
C. Pralidoxime
Explanation
Pralidoxime is the correct additional drug to be used in combination with atropine for the treatment of the patient in Question 10. Atropine is commonly used to treat symptoms of organophosphate poisoning, such as excessive salivation, sweating, bronchospasm, and bradycardia. Pralidoxime is another medication used in the treatment of organophosphate poisoning, as it helps to reactivate the enzyme acetylcholinesterase, which is inhibited by organophosphates. By combining atropine and pralidoxime, the effects of organophosphate poisoning can be effectively counteracted.
34.
A 65-year-old man with the diagnosis of Alzheimer’s disease is being treated with donepezil. This drug acts by
Correct Answer
E. Inhibiting AChE.
Explanation
Donepezil is a medication used to treat Alzheimer's disease. It works by inhibiting acetylcholinesterase (AChE), an enzyme that breaks down acetylcholine (ACh) in the brain. By inhibiting AChE, donepezil increases the levels of ACh in the brain, which helps to improve cognitive function in individuals with Alzheimer's disease. Therefore, the correct answer is inhibiting AChE.
35.
A 72-year-old woman receives succinylcholine as an adjuvant muscle relaxant during knee surgery. This drug acts by
Correct Answer
C. Increasing Na+ and K+ permeability of the postsynaptic neuromuscular membrane.
Explanation
Succinylcholine acts by increasing the permeability of Na+ and K+ ions in the postsynaptic neuromuscular membrane. This leads to depolarization of the muscle fiber and subsequent muscle relaxation. Blocking ACh at nicotinic receptors of the neuromuscular endplate, blocking ACh at nicotinic receptors in the adrenal medulla, blocking the transmission of the action potential along the nerve axon, and blocking the release of ACh from neuromuscular presynaptic vesicles are not the correct mechanisms of action for succinylcholine.
36.
A 3-year-old boy is brought to the emergency room because he has ingested a large amount of a nicotine-containing product. Serious nicotine toxicity in this child is the result of
Correct Answer
A. Blockade of transmission at autonomic ganglia and neuromuscular junctions.
Explanation
Ingesting a large amount of a nicotine-containing product can lead to serious nicotine toxicity. Nicotine acts by binding to and activating nicotinic acetylcholine receptors (nAChRs) in the autonomic ganglia and neuromuscular junctions. When these receptors are activated, transmission at these sites is facilitated. However, in this case, the child is experiencing serious nicotine toxicity, which suggests that there is a blockade of transmission at these autonomic ganglia and neuromuscular junctions instead. This blockade can lead to various symptoms such as muscle weakness, respiratory distress, and cardiovascular effects.
37.
A 53-year-old woman with COPD is using an albuterol inhaler for symptomatic relief of bronchospasm. She does not like using her inhaler because it causes
Correct Answer
B. Her heart to beat faster.
Explanation
The correct answer is "her heart to beat faster." Albuterol is a bronchodilator medication that works by relaxing the muscles in the airways, allowing for easier breathing. One of the common side effects of albuterol is an increased heart rate or palpitations. This occurs because albuterol can stimulate the beta-2 adrenergic receptors in the heart, leading to an increase in heart rate. It is important for patients with COPD to be aware of this side effect and to monitor their heart rate while using albuterol.
38.
A 34-year-old woman has been frequently using a nasal spray containing the α adrenergic receptor agonist oxymetazoline for nasal decongestion. She has recently noticed that it is less effective and her symptoms are worse. T is loss of efficacy is most likely due to
Correct Answer
E. Rebound hyperemia of her nasal mucosa
Explanation
The loss of efficacy of the nasal spray is most likely due to rebound hyperemia of the nasal mucosa. Rebound hyperemia occurs when the blood vessels in the nasal mucosa dilate excessively after the vasoconstrictive effects of the nasal spray wear off. This can lead to worsening symptoms and decreased effectiveness of the spray.
39.
A 32-year-old woman with the diagnosis of a pheochromocytoma is scheduled for surgery to remove her adrenal tumor. The best drug to control her episodes of severe hypertension prior to surgery would be
Correct Answer
A. A nonselective &alpHa; adrenergic antagonist such as pHenoxybenzamine.
Explanation
The correct answer is a nonselective α adrenergic antagonist such as phenoxybenzamine. Pheochromocytoma is a tumor of the adrenal glands that secretes excessive amounts of catecholamines, leading to severe hypertension. α adrenergic antagonists block the effects of catecholamines on α receptors, reducing blood pressure. Phenoxybenzamine is a nonselective α adrenergic antagonist and is the drug of choice for preoperative management of pheochromocytoma. Selective α2 adrenergic receptor agonists, selective β2 adrenergic receptor agonists, nonselective β adrenergic receptor antagonists, and selective α1 adrenergic receptor antagonists are not recommended for this condition.
40.
The typical dose of oral propranolol for the treatment of hypertension is 320 mg/day. The typical dose of IV propranolol to treat a life-threatening arrhythmia is 1 to 3 mg administered slowly. The reason for the discrepancy in these doses is
Correct Answer
B. The IV dose avoids the “first pass” metabolism of oral propranolol.
Explanation
The reason for the discrepancy in the doses of oral and IV propranolol is that the IV dose avoids the "first pass" metabolism of oral propranolol. When a drug is taken orally, it first passes through the liver before entering the systemic circulation. This process, known as first pass metabolism, can lead to the breakdown and inactivation of a significant portion of the drug. By administering propranolol intravenously, the drug bypasses the liver and enters the systemic circulation directly, resulting in a higher bioavailability and therefore a lower required dose compared to oral administration.
41.
A 32-year-old woman is taking sertraline for mild depression. This drug increases the availability of serotonin (5-HT) at the postsynaptic membrane because it
Correct Answer
C. Inhibits the presynaptic uptake of 5-HT.
Explanation
Sertraline is a selective serotonin reuptake inhibitor (SSRI), which means it inhibits the presynaptic uptake of serotonin (5-HT). This means that sertraline prevents the reuptake of serotonin into the presynaptic neuron, allowing more serotonin to remain in the synaptic cleft and increase its availability at the postsynaptic membrane. This mechanism of action helps to alleviate symptoms of depression by increasing serotonin levels in the brain.
42.
Clinical studies have shown that adrenoceptor blockers have many useful effects in patients. However, a number of drug toxicities have been documented. Adverse effects that limit the use of adrenoceptor blockers include which one of the following?
Correct Answer
B. Acute heart failure exacerbation from β blockers
Explanation
Clinical studies have shown that adrenoceptor blockers have many useful effects in patients. However, one of the adverse effects that limit the use of adrenoceptor blockers is acute heart failure exacerbation from β blockers. This means that β blockers can worsen heart failure symptoms in patients, making it a potential risk for those with heart failure.
43.
A 56-year-old man who has a 30-year history of smoking cigarettes is being treated for schizophrenia with clozapine. He is hospitalized for an acute exacerbation of his psychoses; his clozapine therapy is continued. During the third week of his hospital stay, he has a seizure that is thought to be due to clozapine toxicity. The clozapine toxicity in this patient is likely due to
Correct Answer
D. Decreased metabolism of clozapine.
Explanation
The correct answer is decreased metabolism of clozapine. Clozapine is primarily metabolized by the liver, specifically by the cytochrome P450 enzyme system. In individuals with decreased liver function, such as those with liver disease or older age, the metabolism of clozapine may be impaired. This can lead to higher levels of the drug in the body, increasing the risk of toxicity. In this case, the patient's long history of smoking cigarettes may have contributed to liver dysfunction, resulting in decreased metabolism of clozapine and subsequent toxicity.
44.
A 22-year-old woman is being treated with amitriptyline or depression. She, and her family, should be cautioned about not seeing a therapeutic effect for
Correct Answer
E. 3 to 4 weeks.
Explanation
The therapeutic effect of amitriptyline for depression may take 3 to 4 weeks to become noticeable. It is important for the woman and her family to be aware of this timeframe to manage their expectations and avoid premature discontinuation of the medication.
45.
A 75-year-old man with obsessive compulsive disorder is treated with risperidone. After 3 weeks of therapy, he develops bradykinesia, masked facies, and reduced arm movements when walking. These symptoms are due to
Correct Answer
D. D2 receptor antagonism.
Explanation
The symptoms described, including bradykinesia (slowness of movement), masked facies (reduced facial expression), and reduced arm movements when walking, are characteristic of parkinsonism. These symptoms are commonly associated with D2 receptor antagonism, which is a known side effect of risperidone, an atypical antipsychotic medication. D2 receptor antagonism can lead to a decrease in dopamine activity in the brain, resulting in the development of parkinsonian symptoms.
46.
A 43-year-old woman is being treated with olanzapine for schizophrenia. Although olanzapine appeared to be improving her behavioral symptoms, she stopped using the drug likely due to
Correct Answer
C. Weight gain.
Explanation
The most likely reason for the woman to stop using olanzapine is weight gain. Olanzapine is an atypical antipsychotic medication commonly associated with significant weight gain as a side effect. This can be concerning for patients, as weight gain can lead to various health issues and impact their overall well-being. Therefore, the woman may have decided to discontinue the medication due to this side effect.
47.
A 36-year-old woman presents with symptoms of major depression that are unrelated to a general medical condition, bereavement, or substance abuse. She is not currently taking any prescription or over-the-counter medications. Drug treatment is to be initiated with sertraline. In your information to the patient, you would tell her that
Correct Answer
E. All of the above
Explanation
The explanation for the correct answer "All of the above" is that all of the statements provided are true and relevant to the patient's treatment with sertraline. Sertraline is an antidepressant medication that may take 2 weeks or more to show its full effectiveness. It is generally recommended to take the drug in the morning to minimize the risk of insomnia. Muscle cramps and twitches can be potential side effects of sertraline. It is important for the patient to notify the healthcare provider if she anticipates using other prescription drugs to avoid potential drug interactions.
48.
SSRIs are much less effective than tricyclic antidepressants in the management of
Correct Answer
B. Chronic pain of neuropathic origin
Explanation
Tricyclic antidepressants are more effective than SSRIs in managing chronic pain of neuropathic origin. This is because tricyclic antidepressants have a stronger analgesic effect and can help alleviate the neuropathic pain symptoms more effectively. SSRIs, on the other hand, are commonly used for the treatment of depression and anxiety disorders but have limited efficacy in managing chronic pain. Therefore, for patients with chronic pain of neuropathic origin, tricyclic antidepressants would be a more suitable treatment option.
49.
A 19-year-old college student has overdosed on phenobarbital. After standard supportive care, the physician in the ER should do which of the following to hasten the elimination of phenobarbital?
Correct Answer
D. Alkalinize the urine
Explanation
Alkalinizing the urine can help hasten the elimination of phenobarbital. Phenobarbital is a weak acid, and increasing the pH of the urine can promote its ionization and decrease its reabsorption in the renal tubules. This leads to increased excretion of the drug in the urine, effectively eliminating it from the body at a faster rate.
50.
A 32-year-old woman is taking ramelteon for chronic insomnia. Ramelteon binds to
Correct Answer
A. Melatonin receptors M1 and M2.
Explanation
Ramelteon is a medication used to treat chronic insomnia. It works by binding to melatonin receptors M1 and M2. Melatonin is a hormone that regulates the sleep-wake cycle, and by binding to these receptors, ramelteon helps to promote sleep. This explanation aligns with the information provided in the question and accurately describes the mechanism of action of ramelteon.