Pharmacology Chapter9 Questions And Answers

Pharmacology Chapter9 Questions And Answers 1. Which of the following are probable signs of the anaphylactic reaction to bee stings? (A) Bronchodilator, tachycardia, hypertension, vomiting, diarrhea (B) Bronchospasm, tachycardia, hypotension (C) Bronchodilator, bradycardia, vomiting, diarrhea (D) Bronchospasm, bradycardia, hypotension, diarrhea (E) Bronchodilator, tachycardia, vomiting, diarrhea - Answer-Anaphylaxis is caused by the release of several mediators. Leukotriene’s and certain proteins are the most important of these. They cause *bronchospasm* and laryngeal edema and marked *vasodilation with severe hypotension* . *Tachycardia* is a common reflex response to the hypotension. Gastrointestinal disturbance is not as common nor as dangerous. The answer isB. 2. If this child has signs of anaphylaxis, what is the treatment of choice? (A) Diphenhydramine (an antihistamine) (B) Ephedrine (C) Epinephrine (D) Methylprednisolone (a corticosteroid) (E) Phenylephrine - Answer-The treatment of anaphylaxis requires a powerful physiologic antagonist with the ability to cause bronchodilation (β2effect), and vasoconstriction (α effect). *Epinephrine* is the most effective agent with these properties. Antihistamines and corticosteroids are sometimes used as supplementary agents, but the use of epinephrine is mandatory. The answer is C. 3.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 - Answer-*Antimuscarinics* (tropicamide) are mydriatic and cycloplegic; *α-sympathomimetic agonists* are only mydriatic. Isoproterenol has negligible effects on the eye. Norepinephrine penetrates the conjunctiva poorly and would produce intense vasocon-striction. Pilocarpine causes miosis . The answer is C. 4. A 30-year-old man is admitted to the emergency department after taking a suicidal overdose of reserpine. His blood pressure is 50/0 mm Hg and heart rate is 40 bpm. Which of the following would be the most effective cardiovascular stimulant? (A) Amphetamine (B) Clonidine (C) Cocaine (D) Norepinephrine (E) Tyramine - Answer-A large overdose of reserpine causes marked depletion of stored catecholamine transmitter. *The indirect-acting agents* (amphet-amines, cocaine, and tyramine) act through catecholamines in (or released from) the nerve terminal and would therefore be ineffective in this patient. *Clonidine* acts primarily on pre-synaptic nerve endings although it can activate α2 receptors located elsewhere. *Norepinephrine* has the necessary combi-nation of direct action and a spectrum that includes α1,α2,andβ1 effects. The answer is D. 5. An anesthetized dog is prepared for recording blood pressure and heart rate in a study of a new blocking drug. Results show that the new drug prevents the tachycardia evoked by isoproterenol? Which of the following standard agents does the new drug most resemble? (A) Atropine (B) Hexamethonium (C) Phentolamine (an α blocker) (D) Physostigmine (E) Propranolol (a β blocker) - Answer-When considering questions that may involve reflex homeo-static responses, it helps to recall the pathway and receptors involved in the baroceptor reflex. In the case of isoproterenol-induced tachycardia, a reflex is evoked by the β2-mediateddecrease in blood pressure. This reflex will be processed by the vasomotor center and result in increased sympa-thetic autonomic nervous system outflow to the sinus node to increase heart rate. This reflex would be blocked by a ganglion blocker such as hexamethonium. However, isoproterenol also causes tachycardia directly by activating the β receptors in the sinus node, an effect not blocked by gan-glion blockers. Only a β blocker (propranolol) will prevent both the reflex tachycardia and the direct tachycardia induced by isoproterenol. The answer is E. 6. Your new 10-year-old patient has asthma, and you decide to treat her with a β2 agonist. In considering the possible drug effects in this patient, you would note that β2 stimulants frequently cause (A) Direct stimulation of renin release (B) Hypoglycemia (C) Increased cGMP (cyclic guanine monophosphate) in mast cells (D) Skeletal muscle tremor (E) Vasodilation in the skin - Answer-*Tremor is a common β2 effect*. Blood vessels in the skin have almost exclusively α (vasoconstrictor) receptors. Stimulation of renin release is a β1 effect. Beta2 agonists cause hyperglycemia. The answer is D. 7. Mr Green, a 54-year-old man, 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 - Answer-Heart transplantation involves the cutting of autonomic nerves to the heart. As a result, autonomic nerve endings degenerate, and cardiac transmitter stores are absent for 2 years or longer after surgery. Therefore, *indirect-