Autonomic drug interactions — MCQs

In patients with chronic obstructive pulmonary disease, stimulation of muscarinic acetylcholine receptors results in an increase in mucus secretion, smooth muscle contraction and bronchoconstriction. The end result is an increase in airway resistance. Which of the following pharmacologic agents interferes directly with this pathway?

A 43-year-old man is brought to the emergency department 45 minutes after his wife found him on the floor sweating profusely. On arrival, he is lethargic and unable to provide a history. He vomited multiple times on the way to the hospital. His temperature is 37.3°C (99.1°F), pulse is 55/min, respirations are 22/min, and blood pressure is 98/65 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 80%. Examination shows profuse diaphoresis and excessive salivation. He withdraws his extremities sluggishly to pain. The pupils are constricted and reactive. Scattered expiratory wheezing and rhonchi are heard throughout both lung fields. Cardiac examination shows no abnormalities. There are fine fasciculations in the lower extremities bilaterally. Muscle strength is reduced and deep tendon reflexes are 1+ bilaterally. His clothes are soaked with urine and feces. Which of the following is the mechanism of action of the most appropriate initial pharmacotherapy?

A 55-year-old man comes to the physician because of episodic retrosternal chest pain and shortness of breath for the past 6 months. His symptoms occur when he takes long walks or climbs stairs but resolve promptly with rest. He has a history of chronic obstructive pulmonary disease, for which he takes ipratropium bromide. His pulse is 81/min and blood pressure is 153/82 mm Hg. Physical examination shows mild expiratory wheezing over both lungs. Additional treatment with a beta blocker is considered. Which of the following agents should be avoided in this patient?

A 65-year-old male with a history of CHF presents to the emergency room with shortness of breath, lower leg edema, and fatigue. He is diagnosed with acute decompensated congestive heart failure, was admitted to the CCU, and treated with a medication that targets beta-1 adrenergic receptors preferentially over beta-2 adrenergic receptors. The prescribing physician explained that this medication would only be used temporarily as its efficacy decreases within 2-3 days due to receptor downregulation. Which of the following was prescribed?

A 75-year-old male arrives by ambulance to the emergency room severely confused. His vitals are T 40 C, HR 120 bpm, BP 80/55 mmHg, RR 25. His wife explains that he injured himself about a week ago while cooking, and several days later his finger became infected, oozing with pus. He ignored her warning to see a doctor and even refused after he developed fever, chills, and severe fatigue yesterday. After being seen by the emergency physician, he was given antibiotics and IV fluids. Following initial resuscitation with IV fluids, he remains hypotensive. The ED physicians place a central venous catheter and begin infusing norepinephrine. Which of the following receptors are activated by norepinephrine?

A 28-year-old woman, gravida 1, para 0, at 32 weeks' gestation is admitted to the hospital for the management of elevated blood pressures. On admission, her pulse is 81/min, and blood pressure is 165/89 mm Hg. Treatment with an intravenous drug is initiated. Two days after admission, she has a headache and palpitations. Her pulse is 116/min and regular, and blood pressure is 124/80 mm Hg. Physical examination shows pitting edema of both lower extremities that was not present on admission. This patient most likely was given a drug that predominantly acts by which of the following mechanisms?

A researcher is studying receptors that respond to epinephrine in the body and discovers a particular subset that is expressed in presynaptic adrenergic nerve terminals. She discovers that upon activation, these receptors will lead to decreased sympathetic nervous system activity. She then studies the intracellular second messenger changes that occur when this receptor is activated. She records these changes and begins searching for analogous receptor pathways. Which of the following receptors would cause the most similar set of intracellular second messenger changes?

Which neurotransmitter is primarily responsible for parasympathetic effects on heart rate?

A 64-year-old man is brought to the emergency department by his wife with a 2-hour history of diarrhea and vomiting. He says that he felt fine in the morning, but noticed that he was salivating, sweating, and feeling nauseated on the way home from his work as a landscaper. The diarrhea and vomiting then started about 10 minutes after he got home. His past medical history is significant for depression and drug abuse. His wife says that he has also been more confused lately and is afraid he may have ingested something unusual. Physical exam reveals miosis, rhinorrhea, wheezing, and tongue fasciculations. Which of the following treatments would most likely be effective for this patient?

A 58-year-old woman presents to her physician complaining of a headache in the occipital region for 1 week. Past medical history is significant for essential hypertension, managed with lifestyle modifications and 2 antihypertensives for the previous 6 months. Her blood pressure is 150/90 mm Hg. Neurological examination is normal. A third antihypertensive drug is added that acts as a selective α2 adrenergic receptor agonist. On follow-up, she reports that she does not have any symptoms and her blood pressure is 124/82 mm Hg. Which of the following mechanisms best explains the therapeutic effect of this new drug in this patient?