Autonomic/CV Drugs — MCQs

A 27-year-old woman was found lying unconscious on the side of the street by her friend. He immediately called the ambulance who were close to this neighborhood. On initial examination, she appears barely able to breathe. Her pupils are pinpoint. The needles she likely used were found on site but the drug she injected was unknown. The first responders were quick to administer a drug which is effectively used in these situations and her symptoms slowly began to reverse. She was taken to the nearest emergency department for further workup. Which of the following best describes the mechanism of action of the drug administered by the first responders?

A 40-year-old man presents to the emergency department with a chief complaint of chest pain for the last 3 hours. His ECG shows normal sinus rhythm with ST-segment elevation in leads II, III, and aVF and reciprocal segment depression in leads V1–V6. On physical examination, cardiac sounds are normal on auscultation. His blood pressure is 92/64 mm Hg and heart rate is 93/min. A tissue plasminogen activator is administered to the patient intravenously within 1 hour of hospital arrival due to a lack of available percutaneous coronary intervention. After 6 hours of therapy, the patient's clinical condition starts to deteriorate. ECG on the monitor shows accelerated idioventricular rhythm, which within a couple of minutes changes to ventricular fibrillation. Before any measures could be started, the patient deteriorates further and must be transferred to the ICU. What is the most likely etiology of the ECG findings in this patient?

A 50-year-old male is brought to the dermatologist's office with complaints of a pigmented lesion. The lesion is uniformly dark with clean borders and no asymmetry and has been increasing in size over the past two weeks. He works in construction and spends large portions of his day outside. The dermatologist believes that this mole should be biopsied. To prepare the patient for the biopsy, the dermatologist injects a small amount of lidocaine into the skin around the lesion. Which of the following nerve functions would be the last to be blocked by the lidocaine?

An investigator is developing a drug that results in contraction of the pupillary dilator muscle when instilled topically. The drug works by increasing neurotransmitter release from the presynaptic nerve terminal. When administered intravenously, this drug is most likely to have which of the following additional effects?

A 39-year-old man comes to the physician because of frequent urination for the past 2 months. He has been urinating 10–12 times during the day and 3–4 times during the night. He says he is drinking a lot of water to compensate for any dehydration. He has no history of serious illness and takes no medications. Vital signs are within normal limits. Physical examination shows no abnormalities. He is concerned he may have diabetes mellitus like his parents. Laboratory studies show: Hemoglobin 14.3 g/dL Serum Na+ 149 mEq/L K+ 3.9 mEq/L Cl- 102 mEq/L Glucose 90 mg/dL Osmolality 306 mOsmol/kg H2O Urine Osmolality 210 mOsmol/kg H2O A water deprivation test is conducted. After 2 hours of fluid restriction, his plasma osmolality is 315 mOsmol/kg H2O and his urine osmolality is 210 mOsmol/kg H2O. One hour after an ADH analog injection, his plasma osmolality is 276 mOsmol/kg H2O and his urine osmolality is 425 mOsmol/kg H2O. Which of the following is the most appropriate next step in management?

A 36-year-old female presents to her primary care provider for tremor. She reports that she has always had a mild tremor but that she has begun noticing it more since learning to paint. She feels that she has trouble dipping her paintbrush in the paint and making precise strokes on the canvas. She has taken to painting while drinking wine, as she notices that the wine seems to improve her tremor. Her temperature is 97.6°F (36.4°C), blood pressure is 105/61 mmHg, pulse is 58/min, and respirations are 12/min. On exam, she has a high frequency bilateral hand tremor elicited on finger-to-nose testing. Her neurological exam is otherwise unremarkable. The patient is started on a new medication for her symptoms. One week later, she returns with a new complaint of abdominal pain for one day. She reports that she has noticed a darkening of her urine and now has difficulty raising her arms over her head to brush her hair. This patient was most likely treated with which of the following medications?

A 23-year-old G1P0 woman presents to the emergency department with regular and painful contractions that occur every 3 minutes. She was at home cooking dinner when she experienced a deluge of clear fluid between her legs followed by painful contractions. The patient has a past medical history of obesity. Her pregnancy was not followed by an obstetrician, but she notes that she experienced abdominal pain and headaches frequently towards the end of her pregnancy. Her temperature is 99.5°F (37.5°C), blood pressure is 187/128 mmHg, pulse is 110/min, respirations are 17/min, and oxygen saturation is 98% on room air. The patient is started on magnesium sulfate and labetalol. The patient delivers her baby vaginally 2 hours later. On the labor and delivery floor, the patient is notably somnolent. Vitals are notable for respirations of 6 per minute. Physical exam reveals a somnolent woman who is minimally responsive. Cardiopulmonary exam is notable for hypopnea. Neurological exam reveals absent deep tendon reflexes and 3/5 strength in her upper and lower extremities. Which of the following is the next best step in management?

An investigator is studying a drug that acts on the thyroid hormone pathway. Levels of serum free T3 and T4 in healthy participants are measured before and after administration of the drug. After administration, there is a decrease in the average serum free T3 level, while the average serum free T4 level is increased compared to initial serum studies. Inhibition of which of the following is the most likely mechanism of action of this drug?

A 48-year-old man comes to the emergency room for a persistent painful erection for the last 4 hours. Three weeks ago, he had a deep vein thrombosis following a 13-hour flight. He also has a history of sickle cell trait, gastroesophageal reflux disease, major depressive disorder, and hypertension. He has smoked 1 pack of cigarette daily for the past 9 years. He takes warfarin, propranolol, citalopram, trazodone, lisinopril, and omeprazole. He is alert and oriented but in acute distress. His temperature is 37°C(98.6°F), pulse is 109/min, and blood pressure is 139/88 mm Hg. Examination shows a rigid erection with no evidence of trauma, penile discharge, injection, or prosthesis. Which of the following is the most likely cause of his condition?

A 37-year-old woman, gravida 3, para 2, at 28 weeks' gestation comes to the physician for a follow-up examination. One week ago, an oral glucose tolerance screening test showed elevated serum glucose levels. She has complied with the recommended diet and lifestyle modifications. Over the past week, home blood glucose monitoring showed elevated fasting and post-prandial blood glucose levels. Which of the following describes the mechanism of action of the most appropriate pharmacotherapy for this patient?