I. Start the exam by click the “Start” button
The Peripheral Nervous Systems: Autonomic and Somatic Nervous System Pharmacology- Part 2
II. Preview all questions below
1.A patient with a history of narrow-angle (angle-closure) glaucoma experiences a sudden ri se of intraocular pressure that i s sufficiently In addition to pain there i s an imminent ri sk of permanent vis ion loss. They require immediate treatment, one element of which i s administration of echothiophate. What enzyme i s affected by this autonomic drug?
- Tyrosine hydroxylase—stimulated
- Acetylcholinesterase (AChE)—inhibited
- Catechol-O-methyltransferase (COMT)—inhibited
- Monoamine oxidase (MAO)—stimulated
- DOPA decarboxylase—stimulated
2. A patient has essential hypertension, and lab tests would show that their ci rculating catecholamine and plasma renin levels are unusually The chosen therapeutic approach for this patient i s to give a s ingle drug that blocks both α- and β-adrenergic receptors, thereby reducing blood pressure by reducing both cardiac output and total peripheral resistance (systemic vascular resistance). What drug i s most capable of doing that?
3. A man who has been “surfing the Web” in search of an aphrodisiac or some other agent to enhance “sexual prowess and performance” discovers He consumes the drug in excess and develops symptoms of toxicity that require your intervention. You consult your preferred drug reference and learn that yohimbine i s a selective α2-adrenergic antagonist that acts mainly in the brain’s medullary “cardiovascular control center.” What would you expect as a response to this drug?
- Excessive secretions by exocrine glands (salivary, lacrimal, etc)
- Reduced cardiac output from reduced left ventricular contractility
- Rise of blood pressure
4. You plan to prescribe scopolamine, as a transdermal drug delivery system (skin patch), for a patient who will be leaving for an expensive cruise and i s very susceptible to motion s i What comorbidity would weigh against prescribing the drug because i t i s most l ikely to pose adverse effects—or be truly contraindicated?
- Angle-closure (narrow-angle) glaucoma
- History of allergic reactions to uncooked shellfish
- Resting blood pressure of 112/70 Hypothyroidism, mild
- Parkinson disease (early onset, not currently treated)
5. A child overdoses on a drug that affects both the autonomic and somatic nervous As blood levels of the drug ri se he experiences hypertension and tachycardia, accompanied by skeletal muscle tremor. Further elevations of blood levels of the drug cause all the expected s igns and symptoms of autonomic ganglionic blockade, plus weakness and eventual paralysis of skeletal muscle. Which drug did the child most l ikely ingest?
- Pi locarpine
- Propranolol (or another β-adrenergic blocker)
6. Many cl inical studies have shown that propranolol will lower blood pressure to varying degrees in nearly every patient with essential hypertension (ie, high BP of unknown etiology or identifiable causes, such as pheochromocytoma or vasopressor drug overdose). What i s the most likely and physiologically most important mechanism for propranolol’s pressure-lowering effect?
- Induced a baroreceptor reflex that reduces vasoconstriction usually caused by activation of the sympathetic nervous system
- Inhibited catecholamine release from adrenergic nerves and the adrenal medulla (suprarenal medulla)
- Reduced heart rate and left ventricular contractility
- Reduced total peripheral resistance via direct vasodilator actions involving nitric oxide synthesis in endothelial cells
- Stimulated renin release, ultimately leading to enhanced synthesis of vasodilator chemicals such as bradykinin
7. A 35-year-old man who weighs 150 pounds and i s 5 feet 10 inches tall i s transported to the emergency department in severe He complains of episodes of severe, throbbing headaches, profuse diaphoresis, and palpitations. Eighteen months ago his physician told him he i s healthy except for essential hypertension, but he refused medication and has not seen a health care provider for the last year and a half. He denies use of any drugs, whether prescription or over-the-counter, legal or otherwise.
Assessment reveals that he i s tachycardic and has an i rregular pulse (occasional premature ventricular beats are noted on his ECG). Heart rate at rest i s approximately 130 beats/min, sometimes more. His resting blood pressure i s 200/140 mm Hg. These cardiovascular findings are shown in the figure below.
The fi rst year house officer who i s caring for this patient knows that all the orally effective β-adrenergic blockers are approved for use to treat essential hypertension, and concludes that prompt lowering of blood pressure i s essential for this patient. Therefore, he orders intravenous administration of propranolol (at the arrow, above), and a large dose of the drug s ince the symptoms seem severe. Unknown to the physician i s the fact that the patient’s s igns and symptoms are due to a pheochromocytoma (epinephrine-secreting tumor of the adrenal/suprarenal medulla).
What i s the most l ikely ultimate outcome of administering this β-blocker (or any other β-blocker that lacks α-blocking or other vasodilator activity), supplemented with no other medication?
- Heart failure, cardiogenic shock, death
- Long-lasting normalization of heart rate, contractility, and blood pressure
- Normalization of blood pressures but persistence of tachycardia
- Restoration of normal s inus rate and rhythm, but no change of blood pressure from predrug levels
- Sudden and s ignificant ri se of systolic blood pressure and heart rate
8. A patient with chronic obstructive pulmonary disease (COPD, eg, emphysema, chronic bronchitis) i s receiving an orally inhaled muscarinic receptor-blocking drug to maintain What drug belongs to that class?
- Ipratropium (or tiotropium)
- Pi locarpine
9. You give an “effective dose” of atropine to a person who was poisoned with an AChE What structure will continue to be overactivated by the excess ACh after the atropine i s given?
- Airway smooth muscle
- S-A node of the heart
- Salivary and lacrimal glands
- Skeletal muscle
- Vascular smooth muscle
10. The house officer considers prescribing nadolol for a 53-year-old What preexisting condition (comorbidity) would most l ikely contraindicate safe use of this drug?
- Angina pectoris, chronic-stable (effort-induced)
- Essential hypertension
- Heart failure, mild
- Sinus tachycardia
11. A variety of ophthalmic drugs, working by several main mechanisms of action, are useful for managing chronic open-angle Which one reduces intraocular pressure by decreasing the formation of aqueous humor, rather than by changing the s i ze of the pupil(s)?
- Pi locarpine
12. It’s fair to say that epinephrine, norepinephrine, and acetylcholine play the most important roles as endogenous agonists for the various receptors under control of the peripheral nervous However, dopamine also plays a small but important therapeutic role, particularly when administered IV at low doses. What other peripheral effects can dopamine cause at usual therapeutic doses?
- Bronchodilation via relaxation of airway smooth muscles
- Direct activation of pressure receptors (eg, baroreceptors) in response to blood pressure changes triggered by other agonists
- Direct activation of the juxtaglomerular apparatus, release of aldosterone
- Inhibition of epinephrine release from chromaffin cells (eg, cells of the adrenal/suprarenal medulla).
- Regulation of renal blood flow via control of renal arterial tone
13. Guanadrel i s an antihypertensive drug: i t reduces arteriolar constriction, and in doing so lowers BP by reducing the amount of NE in peripheral adrenergic Lowered blood pressure i s not accompanied by reflex tachycardia, and in fact a reduction of heart rate from predrug levels i s the more common outcome. The main ocular effect of guanadrel i s miosis. The widespread abolition of sympathetic influences throughout the body often causes diarrhea and urinary frequency. Based on this description, to which prototypic drug i s guanadrel most s imilar in terms of i ts ultimate qualitative autonomic effects, and in terms of overall mechanism of action?
14. An “effective” dose of a drug i s given and the following responses occur:
- Stimulates heart rate and, apparently, left ventricular stroke volume
- Dilates some blood vessels but constricts none
- Dilates the bronchi (relaxes airway smooth muscles)
- Raises blood glucose levels
- Neither dilates nor constricts the pupil of the eye What drug i s capable of causing all these responses?
15. It i s common to include small amounts of epinephrine (EPI) in solutions of local anesthetics that will be administered by infiltration (injection around sensory nerve endings), as when a skin laceration needs What is the most l ikely reason for, or outcome of, including the EPI?
- To antagonize the otherwise intense and common vasoconstrictor and hypertensive effects of the anesthetic
- To counteract cardiac depression caused by the anesthetic
- To prevent anaphylaxis in patients who are allergic to the anesthetic
- To reduce the ri sk of toxicity caused by systemic absorption of the anesthetic
- To shorten the duration of anesthetic action
16. In your third year of medical school, you are conducting a study on s imilarities and differences between two prototypic drugs, phentolamine and prazosin, as they affect cardiovascular You selected two identical twins to ensure their pharmacogenetic make-up, and so their responses to drugs, i s as nearly identical as possible. One twin will get the phentolamine, the other gets prazosin.
Their cardiovascular parameters at baseline (rest) are identical and normal, and everything else that might have an impact on their drug responses i s normal and, well, identical. They aren’t taking any other drugs.
One twin gets an IV injection of phentolamine. His mean blood pressure falls 20 mm Hg in 20 seconds.
The other gets an IV injection of prazosin at an equally effective dose in terms of the blood pressure response. His mean BP falls by an identical amount, 20 mm Hg, over the same time period, 20 seconds.
Which is the most likely difference you will find in the responses of these two lads, one who got phentolamine and the other who got an equivalent pressure-lowering dose of prazosin?
- Phentolamine will trigger a greater baroreceptor-mediated reflex increase of heart rate and contractility than the prazosin will.
- Prazosin will lead to a bigger reflex positive inotropic and chronotropic response than phentolamine.
- Prazosin will block all reflex cardiac responses because i t also has strong β-blocking activity.
- Prazosin will lead to a greater ri se of cardiac output than phentolamine by selectively blocking norepinephrine-mediated
- VasodilationPhentolamine will reduce left ventricular afterload, prazosin will raise i t.
17. A 48-year-old woman has a history of myasthenia She has been treated with an oral acetylcholinesterase (AChE) inhibitor for several years, and has done well until now. Today she presents in your cl inic with muscle weakness and other s igns and symptoms that could reflect either a cholinergic cris i s (excess dosages of her maintenance drug) or a myasthenic cris i s (insufficient treatment). You will use a rapidly acting parenteral acetylcholinesterase inhibitor to help make the differential diagnosis. Which drug would, therefore, be most appropriate to use?