Autonomic/CV Drugs — MCQs

A 19-year-old South Asian male presents to the family physician concerned that he is beginning to go bald. He is especially troubled because his father and grandfather "went completely bald by the age of 25," and he is willing to try anything to prevent his hair loss. The family physician prescribes a medication that prevents the conversion of testosterone to dihydrotestosterone. Which of the following enzymes is inhibited by this medication?

A 72-year-old Caucasian woman presents with three months of progressive central vision loss accompanied by wavy distortions in her vision. She has hypertension controlled with metoprolol but has no other past medical history. Based on this clinical history she is treated with intravitreal injections of a medication. What is the mechanism of action of the treatment most likely used in this case?

A 51-year-old woman comes to the physician because of daytime sleepiness and dry mouth for one month. She says her sleepiness is due to getting up to urinate several times each night. She noticed increased thirst about a month ago and now drinks up to 20 cups of water daily. She does not feel a sudden urge prior to urinating and has not had dysuria. She has a history of multiple urinary tract infections and head trauma following a suicide attempt 3 months ago. She has bipolar I disorder and hypertension. She has smoked one pack of cigarettes daily for 25 years. Examination shows poor skin turgor. Mucous membranes are dry. Expiratory wheezes are heard over both lung fields. There is no suprapubic tenderness. She describes her mood as "good" and her affect is appropriate. Neurologic examination shows tremor in both hands. Laboratory studies show a serum sodium of 151 mEq/L. Urine osmolality is 124 mOsm/kg H2O. Which of the following is the most likely explanation for this patient's symptoms?

A scientist is studying mechanisms by which cancer drugs work to kill tumor cells. She is working to optimize the function of a drug class in order to reduce toxicity and increase potency for the target. After synthesizing a variety of analogs for the drug class, she tests these new pharmacologic compounds against a panel of potential targets. Assay results show that there is significant binding to a clustered group of proteins. Upon examining these proteins, she finds that the proteins add a phosphate group to an aromatic amino acid sidechain. Which of the following disorders would most likely be treated by this drug class?

Five days after undergoing an open colectomy and temporary colostomy for colon cancer, a 73-year-old man develops severe pain and swelling of the left calf. He was diagnosed with colon cancer 3 months ago. He has hypothyroidism and hypertension. His father died of colon cancer at the age of 68. He does not smoke. Prior to admission, his medications included levothyroxine, amlodipine, and carvedilol. Since the surgery, he has also been receiving unfractionated heparin, morphine, and piperacillin-tazobactam. He is 172 cm (5 ft 8 in) tall and weighs 101 kg (223 lb); BMI is 34.1 kg/m2. He appears uncomfortable. His temperature is 38.1°C (100.6°F), pulse is 103/min, and blood pressure is 128/92 mm Hg. Examination shows multiple necrotic lesions over bilateral thighs. The left calf is erythematous, tender, and swollen. Dorsiflexion of the left foot elicits pain behind the knee. The abdomen is soft and nontender. There is a healing midline incision and the colostomy is healthy and functioning. The remainder of the examination shows no abnormalities. Laboratory studies show: Hemoglobin 13.6 g/dL Leukocyte count 12,100/mm3 Platelet count 78,000/mm3 Prothrombin time 18 seconds (INR = 1.1) Activated partial thromboplastin time 46 seconds Serum Na+ 138 mEq/L Cl- 103 mEq/L K+ 4.1 mEq/L Urea nitrogen 18 mg/dL Glucose 101 mg/dL Creatinine 1.1 mg/dL Which of the following is the most appropriate next step in management?

A 4-year-old boy is brought to the emergency department by his mother after cutting his buttock on a piece of broken glass. There is a 5-cm curvilinear laceration over the patient's right buttock. His vital signs are unremarkable. The decision to repair the laceration is made. Which of the following will offer the longest anesthesia for the laceration repair?

An 11-year-old boy is brought to a pediatrician by his parents with the complaint of progressive behavioral problems for the last 2 years. His parents report that he always looks restless at home and is never quiet. His school teachers frequently complain that he cannot remain seated for long during class, often leaving his seat to move around the classroom. A detailed history of his symptoms suggests a diagnosis of attention-deficit/hyperactivity disorder. The parents report that he has taken advantage of behavioral counseling several times without improvement. The pediatrician considers pharmacotherapy and plans to start methylphenidate at a low dose, followed by regular follow-up. Based on the side effect profile of the medication, which of the following components of the patient’s medical history should the pediatrician obtain before starting the drug?

A 67-year-old man comes to the physician because of numbness and burning sensation of his legs for the past week. He also complains that his stools have been larger and rougher than usual. He has non-Hodgkin lymphoma and is currently receiving chemotherapy with prednisone, vincristine, rituximab, cyclophosphamide, and doxorubicin. He has received 4 cycles of chemotherapy, and his last chemotherapy cycle was 2 weeks ago. His temperature is 37.1°C (98.8°F), pulse is 89/min, and blood pressure is 122/80 mm Hg. Examination shows decreased muscle strength in the distal muscles of the lower extremities. Ankle jerk is 1+ bilaterally and knee reflex is 2+ bilaterally. Sensation to pain, vibration, and position is decreased over the lower extremities. Serum concentrations of glucose, creatinine, electrolytes, and calcium are within the reference range. Which of the following is the most likely cause of this patient's symptoms?

A 58-year-old woman comes to the physician because of a 6-month history of difficulty walking, clumsiness of her arms and legs, and slurred speech. Physical examination shows masked facies and a slow, shuffling gait. When her ankles are passively flexed, there is involuntary, jerky resistance. Treatment is initiated with a combination of levodopa and carbidopa. The addition of carbidopa is most likely to decrease the risk of which of the following potential adverse drug effects?

A 12-year-old boy presents to the pediatrician with complaints of chronic cough for the past two years. The cough is present during the day, especially after returning from school. His school teacher says he does not cough at school. The cough is absent while he is asleep, although it increases during examinations or when he experiences boredom. His mother reports that there was a one-month period where he did not cough, but during that month, he used to shrug his shoulders frequently, especially when he was stressed or fatigued. There is no history of sneezing, nasal discharge, nasal congestion, headache, ear symptoms, or breathing difficulty. Detailed history does not suggest the presence of a mood disorder, obsessive-compulsive symptoms, or attention-deficit/hyperactivity disorder. There is no past history of a known neurological disorder, and there is no history of substance abuse. On physical examination, his vital signs are stable. Examination of his respiratory and cardiovascular systems is normal. However, the pediatrician notes repeated eye blinking; upon asking about eye blinking, the mother reports that he has had this habit since he was almost eight years old. Further inquiry suggests that eye blinking, coughing, and grunting disappear for a few weeks without explanation, only to reappear again. Which of the following drugs is likely to be most effective to control this patient’s symptoms?