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The Peripheral Nervous Systems: Autonomic and Somatic Nervous System Pharmacology- Part 4
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1.“First-generation” (older) histamine H1 blockers such as diphenhydramine, phenothiazine antipsychotic drugs (eg, chlorpromazine), and tri – cyclic antidepressants (eg, imipramine) have pharmacologic actions, s ide effects, toxicities, and contraindications that are very s imilar to those of which other drug?
2. A 6-year-old i s transported to the Emergency Department by a parent, who says the boy took a large amount of an allergy The sole active ingredient in the product the parent mentions i s diphenhydramine, and i t i s clear the child i s experiencing toxicity from an overdose. The intern, fresh out of medical school, orders parenteral administration of neostigmine, and the medication order i s not questioned. What adverse effect of the diphenhydramine will persist following neostigmine administration?
- Bronchoconstriction and wheezing
- Delirium, hallucinations, and other CNS manifestations of toxicity
- Profuse secretions from lacrimal, mucus, and sweat glands
- Skeletal muscle tremor or fasciculations
3. In between your M1 and M2 years you are volunteering in a hospital in a very poor part of the Their drug selection i s l imited. A patient presents with acute cardiac failure, for which your preferred drug i s dobutamine, given intravenously. However, there i s none available. Which other drug, or combination of drugs, would be a suitable alternative, giving the pharmacologic equivalent of what you want the dobutamine to do? (All these drugs are available in parenteral formulations.)
- Dopamine (at a very high dose)
- Ephedrine plus propranolol
- Norepinephrine plus phentolamine
- Phenylephrine plus atropine
4. In general, structures that are affected by sympathetic influences respond to both sympathetic neural activation and to the hormonal component, epinephrine released from the adrenal Which structure/function i s unique in that i t responds to epinephrine, but not norepinephrine, and has no direct sympathetic neural control?
- Airway (tracheal, bronchiolar) smooth muscle: relaxation
- Atrioventricular node: increased automaticity and conduction velocity
- Coronary arteries: constriction
- Iri s of the eye: dilation (mydriasis)
- Renal juxtaglomerular apparatus: renin release
5. Adrenergic nerves to the heart are activated, leading to a reflex increase of heart rate and cardiac contractility, in response to a sudden and s ignificant fall of blood pressure. Those sympathetic nerves release norepinephrine (NE). What i s the main physiologic mechanism by which the actions of the released NE are terminated?
- Diffusion away from postsynaptic receptors
- Hydrolysis by nonspecific deaminases
- Metabolic inactivation by MAO
- Metabolic inactivation by catechol-O-methyltransferase
- Reuptake into the adrenergic nerve from which the NE was released
6. The figure below shows several responses measured in a subject (healthy; receiving no other drugs) at rest (before) and after receiving a dose of an unknown Note: The blood pressures shown can be considered mean blood pressure; the fall caused by the unknown was mainly due to a fall of diastolic pressure.
Which drug most l ikely caused the observed responses?
7. A 59-year-old man has a history of emphysema from 40 years of cigarette smoking; hypercholesterolemia that i s being managed with atorvastatin; and Stage 2 essential hypertension for which he i s taking He presents in cl inic today with his main new complaints: nocturia, urinary frequency, and an inability to urinate forcefully and empty his bladder. Following a complete work-up, the physician arrives at a diagnosis of benign prostatic hypertrophy (BPH). We start daily therapy with tamsulosin. What i s the most l ikely s ide effect the patient may experience from the tamsulosin, and about which he should be forewarned?
- Increased ri sk of statin-induced skeletal muscle pathology
- Orthostatic hypotension
- Photophobia and other painful responses to bright l ights
- Wheezing or other exacerbations of the emphysema
8. A patient walks out of the ophthalmologist’s office and into bright sunlight after a comprehensive eye exam, for which he received a topical ophthalmic The drug has not only dilated his pupils, but also impaired his ability to focus his eyes up-close.
The drug this patient received was most l ikely classified as, or worked most s imilar to, which prototype?
- Pi locarpine
9. You’ve received approval from the Institutional Review Board to study the in vi tro (ti ssue bath) responsiveness of i solated human arteriolar segments (obtained during surgery) to a variety of pharmacologic and other The ti ssue samples are 1 cm-long “cylinders” of otherwise-normal (but now denervated) arterioles obtained from the lower legs of patients undergoing amputation surgery.
The setup allows you to perfuse the vessels with a solution that will keep the ti ssue functionally and structurally intact for many hours; to monitor and change perfusion pressure (mm Hg; analogous to “blood pressure” in the intact organism) and perfusate flow (mL/min); and to assess the effects of various vasoactive drugs on the system.
You add ACh to the perfusate to give a concentration identical to the plasma concentration of ACh that causes “expected responses” in an intact human.
Under this experimental setup, adding ACh causes a ri se of perfusion pressure and a decrease of flow, both of which basically reflect vasoconstriction.
What i s the most l ikely explanation for these findings?
- ACh released norepinephrine from the endothelium, which caused vasoconstriction
- Atropine was added to the ti ssue bath before adding the ACh
- Botulinum toxin was added to the bath before adding the ACh
- The vascular endothelium has been damaged or removed (denuded)
- This response i s precisely what we’d expect with injection of ACh into the intact human
10. A 33-year-old woman becomes poisoned after receiving an injection of i l l i ci tly prepared and overly concentrated botulinum What i s the main neurochemical mechanism by which this Clostridium toxin causes i ts effects?
- Directly activates all muscarinic and nicotinic receptors
- Inhibits ACh release from all cholinergic nerves
- Prevents neuronal norepinephrine reuptake
- Releases norepinephrine via a nonexocytotic process
- Selectively and competitively blocks nicotinic receptors
11. A 43-year-old woman with diagnosed myasthenia gravis, and taking pyridostigmine daily, presents in the neurology cl inic with profound skeletal muscle You are unsure whether she i s experiencing a cholinergic cris i s or a myasthenic cris i s , so you administer a usually appropriate diagnostic dose of parenteral edrophonium. Assume the patient was actually experiencing a cholinergic cris i s . What i s the most l ikely response to the edrophonium?
- Hypertensive cris i s from peripheral vasoconstriction
- Myocardial i schemia, and angina, from drug-induced tachycardia and coronary vasoconstriction
- Premature ventricular contractions from increased ventricular automaticity
- Prompt improvement of skeletal muscle tone and function
- Ventilatory distress or failure
12. A patient takes a massive overdose of diphenhydramine, suffering not only s ignificant CNS depression but also numerous and serious peripheral autonomic s ide By what mechanism did diphenhydramine exert i ts untoward peripheral autonomic actions?
- Activation of both β1 and β2 adrenoceptors
- Blockade of α-adrenergic receptors
- Competitive antagonism of ACh actions on muscarinic receptors
- Massive, direct overactivation of ganglionic nicotinic receptors
- Sudden release of epinephrine from the adrenal medulla (suprarenal medulla)
13. A patient with a recent drug poisoning i s transported to the emergency The physician correctly orders administration of pralidoxime as part of the comprehensive emergency treatment plan. Which best describes who the patient was?
- A 13-year-old boy who to took an overdose of methylphenidate for his ADD/ADHD.
- A 43-year-old who took an overdose of neostigmine, prescribed for her myasthenia gravis, in a suicide attempt.
- A 6-year-old who got into the family medicine cabinet and took 10 “adult doses” of her dad’s prazosin.
- A farm/field worker accidentally doused with insecticide from an overflying crop-duster plane.
- An asthma patient who accidentally gave himself an intravenous injection of epinephrine in an attempt to self-treat a developing anaphylactic reaction.
14. To facilitate a certain eye exam you want to cause mydriasis, but not alter normal control of All of the following drugs are available as topical ophthalmic formulations. Which one will dilate the pupil without altering accommodation?
- Pi locarpine
15. A 26-year-old woman has rhinorrhea, excessive lacrimation, and ocular congestion from a bout with the common Diphenhydramine provides symptomatic relief. What i s the most l ikely mechanism by which this drug relieved her symptoms?
- α-adrenergic activation (agonist, vasoconstrictor)
- β-adrenergic blockade
- Calcium channel blockade
- Histamine (H2) receptor blockade
- Muscarinic receptor blockade
16. You have treated dozens of patients with acute hypotension from various causes, including overdoses of antihypertensive drugs, all of which can cause Your usual approach to restoring blood pressure, and one that has worked well every time before, i s to inject x mg of phenylephrine intravenously. Today a patient with severe drug-induced hypotension presents in the Emergency Department. He has been taking this drug for many months. He i s not volume-depleted, nor hemorrhaging. You give the phenylephrine at the same dose and by the same route as you always have. It causes no change of blood pressure. Which drug did the patient most l ikely take and overdose on?
17. This i s a strange day for you in the ED. Now you have to treat another normovolemic patient with acute drug-induced hypotension, and give the usually correct and effective dose of This time the drug causes a vasopressor response that i s far greater than you’ve ever encountered when giving the very same dose: systolic pressure ri ses dramatically, i f not dangerously. What drug did the patient most l ikely take?
18. A patient who will be new to your practice makes an appointment for their fi rst vis i t. Your nurse asks them to bring in all their current prescribed medications and any OTC drugs they take They comply. One OTC drug i s a popular brand-name product that contains doxylamine as i ts sole active ingredient. Which property or characteristic best describes this drug?
- Likely to lower heart excessively
- May be a cause of diarrhea that the patient says he often gets
- Should not be used by patients with prostatic hypertrophy or angle-closure glaucoma
- Tends to raise blood pressure through a typical catecholamine-like vasoconstrictor (α-adrenergic) mechanism
- Used during the day, helps them keep awake and alert via a weak amphetamine-like action in the CNS