Block 9 Pharm Adrenergic W Exp Prt 2
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A 12-year-old boy was stung by a wasp while walking in the woods. Few minutes later he developed pruritus and erythema, a generalized feeling of warm and impending doom, dyspnea, wheezing and dizziness. Increasing swelling of the face, eyes, lips and tongue was prominent. Paramedics were called and they administered a SC drug upon arrival. Which of the following drugs was most likely given?
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Norepinephrine
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Isoproterenol
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Epinephrine
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Ephedrine
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Phenylephrine
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About This Quiz
This quiz assesses knowledge of adrenergic agonists, focusing on their therapeutic uses, effects, and interactions in various medical scenarios. It is designed for medical students and professionals to test their understanding of pharmacological applications and patient management.
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- 2.
A 22-year-old man complained to his physician that his nasal stuffiness was getting worse. The man started two days ago an over-the-counter topical preparation containing phenylephrine because of an annoying common cold. Initially the preparation was effective but later the patient noticed that when the drug effect subsided, nasal stuffiness was worse than it originally had been. Which of the following statements best explains this averse drug effect?
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Poor patient compliance
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Insufficient dosing
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Drug induced increased blood pressure
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Drug induced reflex bradycardia
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Drug induced allergic reaction
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Rebound congestion
Correct Answer
A. Rebound congestionExplanation
Answer: F
Phenylephrine is an alpha-1 agonist frequently used locally as nasal decongestant because of
the vasoconstricting effects on nasal mucosa. The most common adverse effect of topical nasal
decongestants is rebound nasal congestion that mainly occurs after 2-3 days of use, like in the
present case.
A, B, C, D, E) These drugs do not cause vasoconstriction and are not used as nasal
decongestants.Rate this question:
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- 3.
A 65-year-old man is undergoing a prostate biopsy because of a suspected prostate cancer. Before the operation the prostate is infiltrated with a solution of lidocaine plus epinephrine in order to provide local anesthesia. Which of the following statements best explains why epinephrine prolongs the effect of lidocaine in this patient?
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It inhibits microsomal enzymes which metabolize lidocaine
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It blocks Ca++ channels in prostate nerves
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It constricts prostate vessels
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It blocks Na+ channels in prostate nerves
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It relaxes prostate capsule
Correct Answer
A. It constricts prostate vesselsExplanation
Answer: C
Epinephrine is used quite often together with local anesthetics, since vasoconstriction localizes
the anesthetic at the desired site, so prolonging the local anesthetic action.
A, B, D, E) All these listed options are quite unlikely.Rate this question:
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- 4.
A 6 year-old girl presented to the family physician in company of her mother, who was distraught over the teacher’s comment that the child was “unmanageable” at school. The teacher had referred that the girl was unable to remain seated for the duration of a structured activity and to listen when spoken to directly. She also often fidgeted with hands and feet, squirmed and talked excessively. Similar symptoms were noted during the doctor’s visit. Which of the following drugs would be appropriate to treat this condition?
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Phenylephrine
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Epinephrine
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Albuterol
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Dextroamphetamine
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Norepinephrine
Correct Answer
A. DextroamphetamineExplanation
Answer: D
The signs and symptoms of the patient strongly suggests the diagnosis of attention-deficit/
hyperactivity disorder, which is the single most common chronic behavior disorder in
preadolescent children. Pychostimulants are the most extensively prescribed medications to
treat this disorder. Methylphenidate is the most commonly prescribed drug but
dextroamphetamine is equally effective. Pychostimulants significantly improve attention and can
produce long lasting improvement in academic performance. They normalize classroom behavior
and improve peer interactions and self-esteem.
A, B, C, E) These drug are of no value in attention-deficit/ hyperactivity disorder.Rate this question:
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- 5.
A 56-year-old woman suffering from idiopathic orthostatic hypotension is brought unconscious to the emergency department. She regains consciousness after a supportive treatment and an IV administration of phenylephrine. Which of the following actions most likely account for the therapeutic effectiveness of the drug in the present case?
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Dilation of cerebral vessels
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Increased heart rate
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Increased cardiac output
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Increased systemic blood pressure
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Increased levels of angiotensin II
Correct Answer
A. Increased systemic blood pressureExplanation
Answer: D
The history of the patient suggest that the syncope is most likely due to inadequate cerebral
perfusion. There is a long history of successful clinical use of alpha-1 agonists in case of chronic
postural hypotension. The therapeutic effectiveness of these drugs is due to the
vasoconstriction, which increases both the systolic and diastolic blood pressure, so improving
cerebral blood flow.
A) Cerebral blood flow mainly depends on autoregulation, which can maintain a normal blood
flow at arterial pressure of 60 -140 mm Hg. Therefore, in spite of the strong sympathetic
innervation of cranial vessels, it has long being stated that sympathetic activity plays little role in
controlling cerebral blood flow. In any case an alpha agonist would constrict, not dilate, cerebral
vessels.
B) Alpha-1 agonists actually decrease the heart rate since the increase in systolic and diastolic
blood pressure activates the baroreceptor reflex.
C) Cardiac output is usually little affected by Alpha-1 agonists. By decreasing the heart rate they
would decrease cardiac output, but they would increase it by increasing, venous return, which in
turn increases preload. These opposite actions cancel each other, in most cases.
E) Beta-1 agonists, not alpha-1 agonists, activate the renin-angiotensin systemRate this question:
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- 6.
A 52-year-old woman, recently diagnosed with severe bronchial asthma, complained to her physician of tremors, muscle cramping, palpitations and anxiety. She had started an appropriate therapy two weeks previously. Which of the following drugs most likely caused the patient’s symptoms?
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Isoproterenol
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Salmeterol
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Propranolol
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Dobutamine
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Prazosin
Correct Answer
A. SalmeterolExplanation
Answer: B
Beta-2 agonists by inhalatory route are first line drugs for asthma. Tremor is the most frequent
adverse effect of beta-2 agonists (up to 40% of patients). It likely occurs because
beta-2 receptors activation accelerates the sequestration of cytosolic Ca++ (by opening Ca++
channels in the sarcoplasmic reticulum of skeletal muscle) and increases discharge in muscle
spindles. Anxiety is the second most frequent adverse effects of these drugs (up to 20% of
patients).
Palpitations can occur in up to 10% of patients and is related to the cardiac effects of these
drugs (beta-2 specificity is never absolute and, moreover also beta-2 receptors activation
increases heart contractility and rate). Muscle cramping is likely a consequence of hypokalemia
(beta-2 agonists stimulate Na/K+ ATPase, so facilitating K+ entry into the cells), since K+ is
needed for vasodilation in the skeletal muscle.
A) Isoproterenol can cause the pattern of adverse effects reported by the patient but is very
rarely used today in asthmatic patients.
C, D, E) These drugs are not used to treat asthmatic patients.Rate this question:
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- 7.
Which of the following statements correctly pairs the adrenergic agonist with its appropriate therapeutic use?
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Ephedrine - insomnia
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Dopamine - oliguria due to insufficient renal blood flow
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Dobutamine - anaphylactic shock
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Norepinephrine - neurogenic migraine
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Albuterol -intrauterine fetal death
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Salmeterol - exertional angina
Correct Answer
A. Dopamine - oliguria due to insufficient renal blood flowExplanation
Answer: B
Dopamine is the drug of choice in case of oliguria due to insufficient blood flow. This kind of
oliguria occurs most often in case of acute cardiac failure when the low cardiac output cannot
maintain a sufficient blood flow. Therapeutic doses of dopamine can increase cardiac output by
activating beta-1 receptors and, at the same time, they can dilate the renal vessel by activating
D1 receptors. Therefore renal blood flow can be significantly increased.
A) Ephedrine is a mixed acting sympathomimetic drug that can center the brain and can have
actions similar to those of amphetamine. Therefore insomnia is a contraindication, not an
indication, for the use of this drug.
C) Dobutamine is a drug of choice in cardiogenic shock, but epinephrine remains the most
appropriate drug for the anaphylactic shock.
D) There is no rationale for the use of norepinephrine in neurogenic migraine.
E) Albuterol is contraindicated, not indicated, since it can decrease uterine contractions. Instead
labor must be induced in case of intrauterine fetal death.
F) Salmeterol is actually contraindicated, not indicated, in exertional angina since it can cause
tachycardia.Rate this question:
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- 8.
A 33-year-old man was brought to the emergency room after a car accident. Upon admission the patient was lucid but completely paralyzed with loss of all sensation and reflex activity below the thorax. Vital signs were: blood pressure 80/40 mm Hg, heart rate 42 bpm, respiration 36 breaths/min. A preliminary diagnosis of spinal shock, due to spinal cord injury, was made and an IV infusion of a drug was started . Which of the following drugs was most likely administered?
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Isoproterenol
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Clonidine
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Norepinephrine
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Albuterol
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Ephedrine
Correct Answer
A. NorepinephrineExplanation
Answer: C
The shock due to the spinal injury is a vasodilatory shock (also called neurogenic or distributive
shock) which occurs because the injured sympathetic nervous system fails to maintain the
arteriolar tone. Drugs with alpha-1 adrenergic activity like norepinephrine and phenylephrine are
used to restore the arteriolar tone so counteracting the decreased blood pressure.
A, B, D) These drug are devoid of alpha-1 adrenergic activity
E) This drug is a mixed-acting adrenergic agonist with a direct alpha-1 adrenergic activity too
weak to be useful in vasodilatory shock.Rate this question:
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- 9.
A 15-year-old girl was treated topically with eye drops during a routine ophthalmoscopic examination. After fifteen minutes the ophthalmologist registered a moderate increase in pupillary diameter, with negligible changes in lens curvature and intraocular pressure. Which of the following drugs was most likely administered to the patient?
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Phenylephrine
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Timolol
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Acetylcholine
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Apraclonidine
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Epinephrine
Correct Answer
A. PhenylephrineExplanation
Answer: A
Phenylephrine is a selective alpha-1 agonist frequently used to facilitate the examination of the
retina. The drug causes mydriasis by contracting the radial muscle of iris which receives only
sympathetic innervation. Since neither M3, nor alpha-2 and beta-2 receptors are activated, lens
curvature and intraocular pressure are not affected
B, C, D, E) All these drugs, given locally, would affect the intraocular pressure.Rate this question:
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- 10.
A 52-year-old man suffering from renovascular hypertension was admitted to the hospital because of 24 hours anuria. Pertinent plasma levels on admission were K+ 7.9 mEq/L, Ca++ 3 mEq/L, creatinine 7 mg/dL, BUN 52 mg/dL. An appropriate therapy was initiated which included albuterol IV. Which of the following statements best explains why this drug was given to the patient?
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To counteract the high creatinine values
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To counteract the hyperkalemia
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To counteract the hypocalcemia
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To increase kidney blood flow
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To activate diuresis
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To improve micturition
Correct Answer
A. To counteract the hyperkalemiaExplanation
Answer: B
The lab values of the patient indicate that he is suffering from acute renal failure, a condition that
can be caused by prolonged renal ischemia (see the patient’s renovascular hypertension). K+
values higher than 6.5 mEq/L require emergency treatment. The therapy includes:
a) agents that antagonize the cardiac effects of hyperkalemia (like calcium which counteract the
depolarizing effect of hyperkalemia).
b) drugs that shift K+ from the extracellular to the intracellular space (like insulin and beta-2
agonists)
c) drugs that enhance K+ elimination (like ion exchange resins that bind K+ in the bowel lumen).
A, C, D, E, F) (see explanation above)Rate this question:
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- 11.
A 28-year-old woman was experiencing preterm labor in the 30th week of a twin gestation. Five hours after receiving tocolytic therapy to suppress preterm labor, progressive dyspnea associated with severe hypoxemia developed. A diagnosis of pulmonary edema was made and the woman was given intubation, oxygen and ventilatory support. A drug from which of the following classes did most likely contribute to the development of the patient’s syndrome?
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Beta-2 antagonists
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Beta-2 agonists
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Prostaglandins
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Alpha-1 agonists
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Alpha-1 antagonists
Correct Answer
A. Beta-2 agonistsExplanation
Answer: B
Pulmonary edema is a fairly well-recognized complication of tocolysis with beta agonist drugs.
The pathophysiology of the syndrome is not fully understood but it has been suggested that it is
a consequence of volume overload caused by the physiologic increase in aldosterone level in
pregnancy coupled with an increase in ADH level due to the beta agonist. In fact it has been
shown that isoproterenol increase ADH secretion, whereas beta-blockers decrease it. In addition
there may be greater intravascular volume expansion with twins, as in the present case.
A, C, D, E) All the other options are quite unlikely.Rate this question:
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- 12.
A 44-year-old man presented to his local doctor complaining of an impaired voluntary raising of the eyelid. Physical examination showed miosis, ptosis, flushed facial skin and loss of sweating over the left side of the body. The physician instilled into the conjunctival sac of each eye one drop of cocaine, then (after washing) one drop of phenylephrine. The size of the pupils before and after the two treatments are shown in the table below. From the above data the physician concluded that there was a localized lesion in which of the following anatomical structures?
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Postganglionic sympathetic nerves innervating the face
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Preganglionic sympathetic nerves innervating the face
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Postganglionic parasympathetic nerves innervating the face
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Preganglionic parasympathetic nerves innervating the face
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Medulla oblongata
Correct Answer
A. Postganglionic sympathetic nerves innervating the faceExplanation
Answer: A
The patient most likely has Horner’s syndrome, a condition that results from interruption of the
sympathetic nerves to the face. The lesion causes vasodilation (loss of the alpha-1 receptormediated
vascular tone), ptosis (loss of the alpha-1 receptor-mediated contraction of the
superior tarsal muscle) miosis (loss of the alpha-1 receptor-mediated contraction of the radial
muscle of the iris) and anhydrosis (loss of sympathetic cholinergic firing to the sweat glands).
The use of adrenergic drugs can help to localize the lesion. In the present case, the lesion is
postganglionic since cocaine (which act by inhibiting the reuptake of catecholamines) does not
dilate the constricted pupil because catecholamines have been lost from the nerve endings in
the iris (in most cases a lesion of the nerve will cause degeneration of the distal portion of that
nerve). In contrast the pupil will dilate in response to epinephrine which directly activates the
alpha-1 receptors of the iris.
B) A lesion of the preganglionic sympathetic nerve would have caused the same clinical picture
but cocaine would have been effective since the postganglionic adrenergic neurons were intact.
C, D) A lesion of either pre or postganglionic parasympathetic nerves would have cause a
completely different clinical picture (mydriasis, no ptosis, etc.)
E) Lesions of the sympathetic pathways in the medulla oblongata would cause symptoms similar
to those due to lesions of the preganglionic sympathetic nerves.Rate this question:
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- 13.
A 58-year-old man underwent surgery for the removal of a necrotic bowel tissue. Five days later he become confused and disoriented. Physical finding included fever of 103 F, blood pressure of 90/50 mm Hg, pulse 130 bpm, respiratory rate 30 breath/min. Pertinent lab values were Paco2 30 mm Hg (normal 33-45), HCO 3- 18 mEq/L (normal 22-28), serum pH 7.31, WBC count 22,000 cells/mm3. Arterial and pulmonary artery catheters were inserted, revealing a cardiac output of 6 L/min and a systemic vascular resistance of 610 dyneCsecCcm-5 (normal 800-1400). A fluid therapy was initiated but one hour later the mean blood pressure was still 60 mm Hg. An IV infusion of a drug was started . Which of the following drugs was most likely administered?
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Isoproterenol
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Epinephrine
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Norepinephrine
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Albuterol
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Clonidine
Correct Answer
A. NorepinephrineExplanation
Answer: C
The signs and symptoms of the patient strongly suggest the diagnosis of septic shock. Signs
consistent with this diagnosis are the high fever, high WBC count, hypotension, tachycardia,
elevated cardiac output and low systemic vascular resistance. Septic shock is a vasodilatory
shock (vasodilation may be partly due to the vasodilating effects of endotoxins or other chemical
mediators). In this kind of shock even if cardiac output is increased, it is inadequate to maintain
a blood pressure that will perfuse the essential organs in the face of a decrease systemic
peripheral resistance. In fact the patient has metabolic acidosis, indicating anaerobic metabolism
and lactic acidosis.
Even if fluid administration is still the mainstay therapy in septic shock, recent evidence suggests
that early aggressive vasopressor support may be the key to a positive outcome. This is
especially true when fluid administration alone fails to restore adequate hear rate, arterial
pressure and urine output. Dopamine is frequently the initial pharmacological agent chosen for
the treatment, but when the systemic vascular resistance is very low, as in the present case,
norepinephrine was found to be superior to dopamine.
A, B, D, E) All these drugs tend to decrease the systemic vascular resistance and are therefore
not indicated in the present case.Rate this question:
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- 14.
A new autonomic drug that does not enter the brain was given IV to healthy volunteers in a phase 1 clinical trial. The cardiovascular effects are tabulated below. Which of the following drugs does the new agent most resemble?
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Dobutamine
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Albuterol
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Isoproterenol
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Norepinephrine
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Phenylephrine
Correct Answer
A. DobutamineExplanation
Answer: A
The drug causes a negligible change in both systolic and diastolic pressure, a small increase in
heart rate and a substantial increase in cardiac output. This suggest that the increase in cardiac
output is mainly due to the increase in stroke volume. In fact: stroke volume (SV) = cardiac
output/heart rate ; therefore: SV control = 5/70 = 71 mL ; SV drug = 7/80 = 87 mL. The ejection
fraction is also substantially increased, indicating that the drug must have beta-adrenergic
activity (remember that the only way to increase the ejection fraction is to increase the
contractility of the heart). Among the listed drug only dobutamine has negligible effect on
diastolic blood pressure and (for unknown reasons), little effect on the heart rate.
B, C; D; E) (see explanation above)Rate this question:
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- 15.
A new autonomic drug that does not enter the brain was given IV to healthy volunteers. The cardiovascular effects are tabulated below: The effects of the new drug are most similar to those of which of the following agents?
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Dobutamine
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Epinephrine
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Isoproterenol
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Norepinephrine
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Phenylephrine
Correct Answer
A. PhenylephrineExplanation
Answer: E
The drug causes a parallel increase in both systolic and diastolic pressure and a concomitant
decrease in heart rate. This pattern suggests that the decrease in heart rate is due to a reflex
vagal discharge. Drugs that cause this effect must be vasoconstricting agents (like
norepinephrine and phenylephrine) devoid of vasodilating activity. In this case however the
stroke volume has increased only slightly (stroke volume(SV) = cardiac output/heart rate ;
therefore: control SV = 5/70 = 71.4 mL ; SV after drug = 4.5/58 = 77.6 mL.) and the ejection
fraction has not changed. Norepinephrine would increase substantially the stroke volume and
the ejection fraction since it has beta-adrenergic activity (remember that the only way to increase
the ejection fraction is to increase the contractility of the heart).
A, B, C, D) (see explanation above)Rate this question:
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.JPG "A new autonomic drug that does not enter the brain was given IV to healthy volunteers
in a phase 1 clinical trial. The cardiovascular effects are tabulated below.
Which of the following drugs does the new agent most resemble?")
.JPG "A new autonomic drug that does not enter the brain was given IV to healthy
volunteers. The cardiovascular effects are tabulated below:
The effects of the new drug are most similar to those of which of the following agents?")
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Mar 20, 2023Quiz Edited by
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Jun 03, 2012Quiz Created by
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