Katzung (CVS) Flashcards
- A 27-year-old compulsive drug user injected a drug he thought was methamphetamine, but he has not developed any signs of methamphetamine action. He has been admitted to the emergency department and antimuscarinic drug overdose is suspected. Probable signs of atropine overdose include which one of the following?
A. Gastrointestinal smooth muscle cramping
B. Increased heart rate
C. Increased gastric secretion
D. Pupillary constriction
E. Urinary frequency
B. Increased heart rate
Atropine is an antimuscarinic drug that blocks the action of acetylcholine at muscarinic receptors. One of the effects of this blockade is an increase in heart rate, or tachycardia. While bradycardia (a slowed heart rate) can sometimes be observed after small doses of atropine, tachycardia is the more characteristic sign of an overdose. Neither gastrointestinal cramping, increased gastric secretion, pupillary constriction, nor urinary frequency are typical signs of atropine or methamphetamine overdose.
Atropine overdose leads to the inhibition of parasympathetic nervous system effects, resulting in symptoms that are often summarized by the phrase “hot as a hare, blind as a bat, dry as a bone, red as a beet, and mad as a hatter.”
- Which of following is the most dangerous effect of belladonna alkaloids in infants and toddlers?
A. Dehydration
B. Hallucinations
C. Hypertension
D. Hyperthermia
E. Intraventricular heart block
D. Hyperthermia
Hyperthermia in Infants: Atropine and other belladonna alkaloids can cause a range of symptoms. In infants, the inability to sweat due to the antimuscarinic effects can lead to a dangerous increase in body temperature, or hyperthermia. This is especially concerning because infants have a limited ability to regulate their body temperature. Enhanced Rationale: The use of atropine-containing eye drops in children has been linked to cases of severe hyperthermia, emphasizing the need for caution when using these medications in pediatric populations.
- Which one of the following can be blocked by atropine?
A. Decreased blood pressure caused by hexamethonium
B. Increased blood pressure caused by nicotine
C. Increased skeletal muscle strength caused by neostigmine
D. Tachycardia caused by exercise
E. Sweating caused by exercise
E. Sweating caused by exercise
Sweating caused by exercise: Atropine’s primary mechanism of action is the blockade of muscarinic receptors. While nicotine can induce a range of effects, including those that mimic the sympathetic and parasympathetic nervous systems, the effects related to blood pressure and heart rate are not typically blocked by atropine. However, sweating, which is mediated by acetylcholine released from sympathetic nerve fibers at sweat glands, can be blocked by atropine. Enhanced Rationale: This highlights the unique role of acetylcholine in mediating sweat production, even though it’s released from sympathetic fibers.
Questions 4-5. Two new synthetic drugs (X and Y) are to be studied for their cardiovascular effects. The drugs are given to three anesthetized animals while the blood pressure is recorded. The first animal has received no pretreatment (control), the second has received an effective dose of a long-acting ganglion blocker, and the third has received an effective dose of a long-acting muscarinic antagonist.
- Drug X caused a 50 mm Hg rise in mean blood pressure in the control animal, no blood pressure change in the ganglion-blocked animal, and a 75 mm mean blood pressure rise in the atropine-pretreated animal. Drug X is probably a drug similar to
A. Acetylcholine
B. Atropine
C. Epinephrine
D. Hexamethonium
E. Nicotine
E. Nicotine
Drug X: The response pattern of Drug X suggests that it acts as a ganglion stimulant. The increased blood pressure response in the atropine-pretreated animal indicates that the drug’s effect might have been partially offset by a compensatory vagal discharge in the control animal. Enhanced Rationale: Nicotine, a known ganglion stimulant, produces similar effects, emphasizing the importance of understanding the interactions between drugs and the autonomic nervous system.
Questions 4-5. Two new synthetic drugs (X and Y) are to be studied for their cardiovascular effects. The drugs are given to three anesthetized animals while the blood pressure is recorded. The first animal has received no pretreatment (control), the second has received an effective dose of a long-acting ganglion blocker, and the third has received an effective dose of a long-acting muscarinic antagonist.
- The net changes in heart rate induced by drug Y in these experiments are shown in the following graph.
Drug Y is probably a drug similar to
A. Acetylcholine
B. Edrohonium
C. Hexamethonium
D. Nicotine
E. Pralidoxime
A. Acetylcholine
Drug Y: The effects of Drug Y suggest that it acts as a direct-acting muscarinic stimulant. The reversal of its effect by a ganglion blocker indicates involvement of the baroreceptor reflex. Enhanced Rationale: Acetylcholine, when given in doses that significantly lower blood pressure, can produce a similar response pattern. This underscores the intricate balance of the autonomic nervous system and how drugs can tip this balance in various directions.
- A 30-year-old man has been treated with several autonomic drugs for 4 weeks. He is now admitted to the emergency department showing signs of drug toxicity. Which of the following signs would distinguish between an overdose of a ganglion blocker versus a muscarinic blocker?
A. Cycloplegia
B. Dry skin in a warm environment
C. Miosis
D. Postural hypotension
E. Tachycardia
D. Postural hypotension
Postural hypotension: Both ganglion blockers and muscarinic blockers can produce a range of symptoms. However, postural hypotension, a drop in blood pressure upon standing, is indicative of sympathetic blockade. Enhanced Rationale: This symptom highlights the role of the sympathetic nervous system in maintaining blood pressure, especially during postural changes.
- Which of the following is an accepted therapeutic indication for the use of antimuscarinic drugs?
A. Atrial fibrillation
B. Botulinum poisoning
C. Chronic obstructive pulmonary disease (COPD)
D. Glaucoma
E. Postoperative urinary retention
C. Chronic obstructive pulmonary disease (COPD)
COPD: Antimuscarinic drugs can be beneficial in conditions like COPD where bronchospasm, or tightening of the airways, is a concern. Enhanced Rationale: By blocking the effects of acetylcholine on the airways, antimuscarinic drugs can help relax and open the airways, improving breathing in conditions like COPD.
- Which of the following is an expected effect of a therapeutic dose of an antimuscarinic drug?
A. Decreased cAMP (cyclic adenosine monophosphate) in cardiac muscle
B. Decreased DAG (diacylglycerol) in salivary gland tissue
C. Increased IP; (inositol trisphosphate) in intestinal smooth muscle
D. Increased potassium efflux from smooth muscle
E. Increased sodium influx into the skeletal muscle end plate
B. Decreased DAG (diacylglycerol) in salivary gland tissue
DAG in salivary gland tissue: Muscarinic receptors play a role in various cellular pathways. Blocking these receptors can impact these pathways and the cellular responses they mediate. Enhanced Rationale: Understanding the cellular effects of drugs provides insights into their broader physiological effects.
- Which one of the following drugs causes vasodilation that can be blocked by atropine?
A. Benztropine
B. Bethanechol
C. Botulinum toxin
D. Cyclopentolate
E. Edrophonium
F. Neostigmine
G. Pralidoxime
B. Bethanechol
Bethanechol: This drug can cause vasodilation by directly activating muscarinic receptors on blood vessel endothelium. Enhanced Rationale: This effect underscores the diverse roles of muscarinic receptors in the body, from the heart to the blood vessels to the glands.
- Which one of the following drugs has a very high affinity for the phosphorus atom in parathion and is often used to treat life-threatening insecticide toxicity?
A. Atropine
B. Benztropine
C. Bethanechol
D. Botulinum
E. Cyclopentolate
F. Neostigmine
G. Pralidoxime
G. Pralidoxime
Pralidoxime: This drug has a high affinity for the phosphorus atom in certain insecticides, making it valuable in treating toxicities from these chemicals. Enhanced Rationale: The ability of pralidoxime to bind to and neutralize these insecticides can be life-saving in cases of poisoning.
Questions 1 and 2. While playing in the garden, a 7-year-old boy is stung by 3 bees. Because he has a previous history of bee sting allergy, he is brought to the emergency department by his mother who is very concerned about a possible anaphylactic reaction.
- Which of the following are probable signs of an anaphylactic reaction to bee stings?
(A) Bronchodilation, tachycardia, hypertension, vomiting, diarrhea
(B) Bronchospasm, tachycardia, hypotension, laryngeal edema
(C) Diarrhea, bradycardia, vomiting
(D) Laryngeal edema, bradycardia, hypotension, diarrhea
(E) Miosis, tachycardia, vomiting, diarrhea
(B) Bronchospasm, tachycardia, hypotension, laryngeal edema
Questions 1 and 2. While playing in the garden, a 7-year-old boy is stung by 3 bees. Because he has a previous history of bee sting allergy, he is brought to the emergency department by his mother who is very concerned about a possible anaphylactic reaction.
- If this child has signs of anaphylaxis, what is the treatment of choice?
(A) Diphenhydramine (an antihistamine)
(B) Ephedrine
(C) Epinephrine
(D) Isoproterenol
(E) Methylprednisolone (a corticosteroid)
(C) Epinephrine
Questions 1 and 2. While playing in the garden, a 7-year-old boy is stung by 3 bees. Because he has a previous history of bee sting allergy, he is brought to the emergency department by his mother who is very concerned about a possible anaphylactic reaction.
- A 65-year-old woman with impaired renal function and a necrotic ulcer in the sole of her right foot is admitted to the ward from the emergency department. She has long-standing type 2 diabetes mellitus and you wish to examine her retinas for possible vascular changes. Which of the following drugs is a good choice when pupillary dilation —but not cycloplegia— is desired?
(A) Isoproterenol
(B) Norepinephrine
(C) Phenylephrine
(D) Pilocarpine
(E) Tropicamide
(C) Phenylephrine
- A 60-year-old woman was told she had hypertension and should be taking antihypertensive medication. She decides to take an herbal medication from an online “holistic pharmacy.” One week after starting the medication, she is found unconscious in her apartment. In the emergency department, her blood pressure is 50/0 mm Hg and heart rate is 40 bpm. Respirations are 20/min; pupils are slightly constricted. Bowel sounds are present. Which of the following would be the most effective cardiovascular stimulant?
(A) Amphetamine
(B) Clonidine
(C) Isoproterenol
(D) Norepinephrine
(E) Tyramine
(D) Norepinephrine
- A group of volunteers are involved in a phase 1 clinical trial of a new autonomic drug. When administered by intravenous bolus, the blood pressure increases. When given orally for 1 week, the blood pressure decreases. Which of the following standard agents does the new drug most resemble?
(A) Atropine
(B) Clonidine
(C) Phentolamine (an a blocker)
(D) Phenylephrine
(E) Propranolol (a ß blocker)
(B) Clonidine
- Your 30-year-old patient has moderately severe new onset asthma, and you prescribe a highly selective 2 agonist inhaler to be used when needed. In considering the possible drug effects in this patient, you would note that 2 stimulants frequently cause
(A) Direct stimulation of renin release
(B) Hypoglycemia
(C) Itching due to increased GMP (cyclic guanine mono-phosphate) in mast cells
(D) Skeletal muscle tremor
(E) Vasodilation in the skin
(D) Skeletal muscle tremor
- Mr Green, a 54-year-old banker, had a cardiac transplant
6 months ago. His current blood pressure is 120/70 mm Hg and heart rate is 100 bpm. Which of the following drugs would have the least effect on Mr Green’s heart rate?
(A) Albuterol
(B) Epinephrine
(C) Isoproterenol
(D) Norepinephrine
(E) Phenylephrine
(E) Phenylephrine
Questions 8 and 9. Several new drugs with autonomic actions were studied in preclinical tests in animals. Autonomic drugs X and Y were given in moderate doses as intravenous boluses. The systolic and diastolic blood pressures changed as shown in the diagram below.
- Which of the following drugs most resembles drug X?
(A) Bethanechol
(B) Epinephrine
(C) Isoproterenol
(D) Methacholine
(E) Phenylephrine
(C) Isoproterenol
The drug X dose caused a decrease in diastolic blood pressure and little change in systolic pressure. Thus, there was a large increase in pulse pressure. The decrease in diastolic pressure suggests that the drug decreased vascular resistance, that is, it must have significant muscarinic or 3-agonist effects. The fact that it also markedly increased pulse pressure suggests that it strongly increased stroke volume, a ß-agonist effect. The drug with these ß effects is isoproterenol (Figure 9-1). The answer is C.
Questions 8 and 9. Several new drugs with autonomic actions were studied in preclinical tests in animals. Autonomic drugs X and Y were given in moderate doses as intravenous boluses. The systolic and diastolic blood pressures changed as shown in the diagram below.
- Which of the following most resembles drug Y?
(A) Bethanechol
(B) Epinephrine
(C) Isoproterenol
(D) Methacholine
(E) Phenylephrine
(E) Phenylephrine
- A new drug was given by subcutaneous injection to 25 normal subjects in a phase 1 clinical trial. The cardiovascular effects are summarized in the table below.
Which of the following drugs does the new experimental agent most resemble?
(A) Atropine
(B) Epinephrine
(C) Isoproterenol
(D) Phenylephrine
(E) Physostigmine
(B) Epinephrine
- A patient presents at the emergency department with threatened anaphylaxis. Respiratory obstruction appears likely if she is not treated immediately. Her past medical history includes hypertension, for which she is receiving an adrenoceptor blocker. The emergency physician plans to use epinephrine to treat her anaphylactic reaction. Which of the following effects of epinephrine would be blocked by prazosin but not by metoprolol?
(A) Cardiac stimulation
(B) Increase of cAMP (cyclic adenosine monophosphate) in fat cells
(C) Mydriasis
(D) Relaxation of bronchial smooth muscle
(E) Relaxation of the uterus
(C) Mydriasis
Mydriasis caused by contraction of the pupillary dilator radial smooth muscle is mediated by a receptors. All the other effects listed are mediated by ß receptors.
- 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?
(A) Bronchoconstriction (from a-blocking agents)
(B) Acute heart failure exacerbation (from ß blockers)
(C) Impaired blood sugar response (with a blockers)
(D) Increased intraocular pressure (with ß blockers)
(E) Sleep disturbances (from a-blocking drugs)
(B) Acute heart failure exacerbation (from ß blockers)
Although chronic heart failure is often treated with certain B blockers, acute heart failure can be precipitated or made worse by any ß blocker. Choices A, C, and E reverse the correct pairing of receptor subtype (a versus B) with effect. Choice D reverses the direction of change of intraocular pressure.
- When given to a patient, phentolamine blocks which one of the following?
(A) Bradycardia induced by phenylephrine
(B) Bronchodilation induced by epinephrine
(C) Increased cardiac contractile force induced by norepinephrine
(D) Miosis induced by acetylcholine
(E) Vasodilation induced by isoproterenol
(A) Bradycardia induced by phenylephrine
Phenylephrine, an a agonist, increases blood pressure and causes bradycardia through the baroreceptor reflex. Blockade of this drug’s d-mediated vasoconstrictor effect prevents the bradycardia.
- Your 75-year-old patient with multiple comorbidities is to receive aß-blocking drug. For which of the following conditions are ß-blocking drugs NOT indicated?
(A) Acute arrhythmias during surgery
(B) Atherosclerotic angina pectoris (angina of effort)
(C) Chronic heart failure
(D) Hypertension
(E) Hypoglycemia in diabetes
(D) Hypertension
The ß blockers have several important cardiovascular indica-tions, including acute arrhythmias, angina, chronic (but not acute) heart failure, and hypertension. In addition they are useful in glaucoma, hyperthyroidism, tremor, and possibly, COPD. However, they mask the signs of hypoglycemia and are potentially hazardous in diabetic patients.
- A 56-year-old man has hypertension and an enlarged pros-tate, which biopsy shows to be benign prostatic hyperplasia.
He complains of urinary retention. Which of the following drugs would be the most appropriate initial therapy?
(A) Albuterol
(B) Atenolol
(C) Metoprolol
(D) Prazosin
(E) Timolol
(D) Prazosin
An a blocker is appropriate therapy in a man with both hypertension and benign prostatic hyperplasia because both conditions involve contraction of smooth muscle containing a receptors. Prazosin is the only a blocker in the list of choices.
- A 32-year-old woman with hypertension wishes to become pregnant. Her physician informs her that she will have to switch to another antihypertensive drug. Which of the following drugs is absolutely contraindicated in pregnancy?
(A) Atenolol
(B) Losartan
(C) Methyldopa
(D) Nifedipine
(E) Propranolol
(B) Losartan
Methyldopa is recommended in pregnancy due to its safety record.
ACE inhibitors and ARBs are contraindicated as they can be teratogenic.
Calcium channel blockers are not contraindicated.
- A patient is admitted to the emergency department with severe tachycardia after a drug overdose. His family reports that he has been depressed about his hypertension. Which one of the following drugs increases the heart rate in a dose-dependent manner?
(A) Captopril
(B) Hydrochlorothiazide
(C) Losartan
(D) Minoxidil
(E) Verapamil
(D) Minoxidil
ACE inhibitors, ARBs, and diuretics do not significantly increase heart rate.
Verapamil and diltiazem inhibit the sinoatrial node and decrease heart rate.
Other direct vasodilators increase heart rate.
- Which one of the following is characteristic of nifedipine treatment in patients with essential hypertension?
(A) Competitively blocks angiotensin II at its receptor
(B) Decreases calcium efflux from skeletal muscle
(C) Decreases renin concentration in the blood
(D) Decreases calcium influx into smooth muscle
(E) Increases calcium excretion in the urine
(D) Decreases calcium influx into smooth muscle
Nifedipine is a calcium channel blocker that lowers blood pressure by reducing calcium influx.
It has no effect on angiotensin-converting enzyme.
Calcium efflux from skeletal muscle cells is not involved.
Plasma renin levels may increase due to reduced blood pressure.
Calcium channel blockers have negligible effects on urine calcium.
- A 73-year-old man with a history of a recent change in his treatment for moderately severe hypertension is brought to the emergency department because of a fall at home. Which of the following drug groups is most likely to cause postural hypotension and thus an increased risk of falls?
(A) ACE inhibitors
(B) Alpha,-selective receptor blockers
(C) Arteriolar dilators
(D) Beta1-selective receptor blockers
(E) Calcium channel blockers
(B) Alpha1-selective receptor blockers
Drug-induced postural (orthostatic) hypotension is due to venous pooling or excessive diuresis.
Alpha-1 blockers like prazosin can exacerbate orthostatic hypotension.
- A significant number of patients started on ACE inhibitor therapy for hypertension are intolerant and must be switched to a different class of drug. What is the most common manifestation of this intolerance?
(A) Angioedema
(B) Glaucoma
(C) Headache
(D) Incessant cough
(E) Ventricular arrhythmias
(D) Incessant cough
Chronic cough is an adverse effect of ACE inhibitors like captopril.
It may be associated with increased bradykinin levels.
ACE inhibitors are commonly used in hypertensive diabetic patients.
ACE inhibitors are not associated with glaucoma.
Angioedema is less common than cough.