Exam 11: Pharmacology and Toxicology

A 31-year-old male farm worker visits the doctor with an itchy rash on his chest. Physical examination reveals a five-centimeter-diameter annular and scaling plaque with central clearing on the chest. KOH preparation of skin scrapings reveals branching septate hyphae, and terbinafine topical application was recommended. Which of the following mechanisms of action explains the antifungal activity of this drug?

A 6-day-old boy in the neonatal intensive care unit has a heart murmur.  The patient was born at 27 weeks gestation and intubated due to surfactant deficiency.  Birth weight was 1.14 kg (2 lb 8 oz).  Temperature is 37 C (98.6 F), blood pressure is 66/12 mm Hg, and pulse is 182/min.  A continuous murmur with systolic accentuation is best heard at the left heart border.  There are bounding femoral and palmar pulses.  Abdominal examination is unremarkable.  Blood culture is sterile. Elevated levels of which of the following substances is most likely contributing to this patient's condition?

A 50-year-old woman comes to the hospital because of epigastric abdominal pain that started after her last meal and has become progressively worse over the past 6 hours. She has had intermittent pain similar to this before, but it has never lasted this long. Abdominal examination is notable for right upper quadrant tenderness to palpation that is worsened by deep inspiration. Her temperature is 39°C (102.2°F). Laboratory studies show leukocytosis. An ultrasound of the abdomen reveals multiple gallstones and gallbladder wall thickening with pericholecystic fluid. The patient is admitted and started on intravenous piperacillin combined with tazobactam.  Which of the following is the most likely reason to use this drug combination in this patient?

A 45-year-old woman visits the office for a check-up on her type 2 diabetes mellitus. After experiencing polyuria, polydipsia, and recurrent vulvovaginal candidiasis, the patient was diagnosed with diabetes three years ago. She tried lifestyle changes first, but there was no significant glycemic improvement, so she was put on metformin. The patient follows her therapy and eats a low-carbohydrate diet. Her mother's osteoporotic fracture has a significant family history. The blood pressure is 134/86 mm Hg, and the pulse rate is 72 / min. The BMI is 33 kg/m2². A physical examination reveals no anomalies. The hemoglobin A1c level measured in the lab is 8.2 percent.   After further discussion, a sodium-glucose cotransporter-2 inhibitor is added to the patient's drug regimen.  Which of the following is the most likely additional effect of the newly prescribed medication?

A 26-year-old woman comes to the physician requesting advice regarding contraception. She previously used condoms but stopped using them a few weeks ago after a condom broke during intercourse. Today, she is interested in other contraceptive options and has asked for a "more reliable and uncomplicated contraceptive method." She was diagnosed with deep vein thrombosis 2 years ago. Her menses occur at regular 30-day intervals with normal flow. Medical history is otherwise unremarkable and she takes no medications. She does not smoke cigarettes. She is sexually active with one male partner and uses condoms inconsistently. Vital signs are within normal limits. Pelvic examination shows no abnormalities. A urine pregnancy test is negative. Which of the following is the most appropriate recommendation regarding contraception for this patient?

A 24-year-old female presents to the physician because of feeling sad over the past few months. She has lost interest in swimming, which she previously found enjoyable. Additionally, she has had trouble getting a full night's sleep and has had trouble concentrating during the day. She has lost 15 pounds since her last visit one year prior. Treatment with medication is initiated.  Three weeks later, the patient is brought to the emergency department by her mother for not sleeping at all for 3 nights.  The patient reports that she does not feel tired despite lack of sleep.  She spent a large amount of money on plane tickets and plans to travel around the world to promote world peace.  Her mother adds that she herself has suffered from severe mood swings in the past.  This patient was most likely started on which of the following medications 3 weeks ago?

A 65-year-old man comes to the physician for a follow-up. He underwent prostatectomy for prostate cancer one year ago. After surgery, his serum prostate-specific antigen (PS A) concentration was 1 ng/mL. Initial staging evaluation revealed no evidence of metastatic disease.  PSA level is now 8 ng/dL, and repeat imaging reveals regional lymphadenopathy.  The patient is prescribed combination therapy with buserelin and bicalutamide.  Which of the following is the main reason for adding bicalutamide to this patient's treatment regimen?

A 28-year-old woman comes to the emergency department because of a 2-day history of dark urine, increasing abdominal pain, and a tingling sensation in her arms and legs. She has a history of epilepsy. Her current medication is phenytoin. She is nauseated and confused. Following the administration of hemin and glucose, her symptoms improve. The beneficial effect of this treatment is most likely due to inhibition of which of the following enzymes?

A 49-year-old woman arrives at the emergency department complaining of squeezing chest pain and profuse sweating for the past two hours. Diabetes mellitus type 2 is a diet-controlled condition. The electrocardiogram shows ST-segment elevation in leads I, aVL, and V1-V4. The patient is immediately taken to the cardiac catheterization laboratory, where it is discovered that the left anterior descending coronary artery is completely occluded. Percutaneous coronary intervention with stenting is used to open the blockage, but she then experiences recurrent and sustained episodes of ventricular arrhythmia. She is given an antiarrhythmic medication that binds preferentially to rapidly depolarizing and ischemic ventricular myocardial fibers while having little effect on normal ventricular myocardium.   Which of the following agents was most likely used in this patient?

Four days after undergoing a total abdominal hysterectomy for atypical endometrial hyperplasia, a 59-year-old woman reports abdominal bloating and discomfort. She has also had nausea without vomiting. She has no appetite despite not having eaten since the surgery and drinking only sips of water. Her postoperative pain has been well controlled on a hydromorphone patient-controlled analgesia (PC A) pump. Her indwelling urinary catheter was removed on the second postoperative day and she is now voiding freely. Although she lays supine in bed for most of the day, she is able to walk around the hospital room with the help of a physical therapist. Her temperature is 36.5°C (97.7°F), pulse is 84/min, respirations are 10/min, and blood pressure is 132/92 mm Hg. She is 175 cm (5 ft 9 in) tall and weighs 115 kg (253 lb); BMI is 38 kg/m2. Examination shows a mildly distended, tympanic abdomen; bowel sounds are absent. Laboratory studies are within normal limits. An x-ray of the abdomen shows uniform distribution of gas in the small bowel, colon, and rectum without air-fluid levels. Which of the following is the most appropriate next step in the management of this patient?

A 48-year-old woman comes to the physician because of recurrent right upper abdominal pain for 3 weeks. The pain usually occurs after meals and tends to radiate to the right shoulder. She reports that she otherwise feels well. She has more energy since she started an intermittent fasting diet and has rapidly lost 9.0 kg (20 lbs). She is 160 cm (5 ft 3 in) tall and weighs 100 kg (220 lb); BMI is 39 kg/m2. Physical examination shows a nontender abdomen. Abdominal ultrasonography shows several small stones in the gallbladder without calcification. When discussing treatment options, she states that she does not wish to undergo surgery and asks about other possibilities. Which of the following is the most appropriate pharmacotherapy to address the underlying cause of this patient's condition?

A 68-year-old woman visits the office because she experiences frequent syncopal attacks. The most recent occurrence happened three days ago while she was making her way to her car and lasted roughly one minute. Even though she was exhausted, she was able to return to her regular activities after that. She had no previous heart palpitations or chest pain. The patient has experienced frequent episodes of intermittent dizziness as well as two similar syncopal episodes in the last two months. Chronic renal disease and hypertension are among the past medical conditions. She regularly takes clonidine, amlodipine, and lisinopril. Pulse rate is 44/min and blood pressure is 155/85 mm Hg. Lung and heart sounds are typical. She stops having syncopal episodes once the offending medication is stopped.   The drug responsible for this patient's episodes most likely functions through which of the following mechanisms?

A 59-year-old man with a history of type 1 diabetes mellitus and depression is brought to the emergency department because of increasing confusion and fever over the past 14 hours. Four days ago, he was prescribed metoclopramide by his physician for the treatment of diabetic gastroparesis. His other medications include insulin and paroxetine. His temperature is 39.9°C (103.8°F), pulse is 118/min, and blood pressure is 165/95 mm Hg. Physical examination shows profuse diaphoresis and flushed skin. There is generalized muscle rigidity and decreased deep tendon reflexes. His serum creatine kinase is 1250 U/L. The antidote for this patient's current condition most likely has which of the following mechanisms of action?

A 60-year-old male is admitted to the hospital after an infectice endocardaitis diagnosis. As part of the patient's treatment, 240 mg of intravenous gentamicin is started.  The pharmacy calculates that, in this patient, gentamicin has a volume of distribution of 30 L, a half-life of 4 hours, and demonstrates first-order and one-compartment kinetics.  Which of the following is the most likely serum drug concentration just before the next dose 8 hours later?

A 26-year-old woman is brought to the emergency department because of a 1-day history of lower abdominal pain and vaginal bleeding. Her last menstrual period was 8 weeks ago. A urine pregnancy test is positive. A pelvic ultrasound shows a normal appearing uterus with an empty intrauterine cavity and a minimal amount of free pelvic fluid. The patient is counseled on recommended medical treatment.  Which of the following is the mechanism of action of the agent of choice for this patient?

A 60-year-old man comes in for a check-up after visiting the emergency room for a cough. The patient was diagnosed with acute bronchitis, and the symptoms were alleviated by symptomatic treatment. During that visit, a chest x-ray revealed no lung abnormalities, but the bones appeared osteopenic. There is no bone pain and no fractures, according to the patient. He has had radiation therapy for prostate cancer and is currently taking leuprolide. The patient has no other health issues and no known drug allergies. He enjoys a glass of wine every day and does not use tobacco or illegal drugs. He follows a healthy diet and exercises on a regular basis Blood pressure is 120/80 mm Hg and pulse is 80/min.  Physical examination shows no abnormalities.  A dual-energy x-ray absorptiometry (DX A) scan shows low bone mineral density.  Which of the following is the most likely underlying mechanism of the observed finding in this patient?

Breast cancer is diagnosed in a 55-year-old woman, who has a breast-sparing mastectomy. The tumor margin was free of invasion, and a sentinel axillary lymph node biopsy revealed no evidence of nodal metastasis. The tumor expressed estrogen and progesterone receptors but not HER-2. Tamoxifen is prescribed after a discussion of treatment options with the patient. She has hot flashes that come and go in waves while taking this medication, which has a significant impact on her sleep. following conditions is the patient also likely to experience as a result of this therapy?

A 10-year-old boy is brought to the physician by his father for follow up care. He was having trouble in school until he was started on ethosuximide by a previous physician. The father says that the patient is doing well and has not had any seizures since starting the medication.  His school performance has improved significantly, Which of the following is the most likely mechanism of action of the medication used in this patient?

A 69-year-old man is brought to the emergency department 30 minutes after sudden onset of painless loss of vision in his right eye. Over the last several years, he has noticed increased blurring of vision; he says the blurring has made it difficult to read, but he can read better if he holds the book below or above eye level. He has smoked 1 pack of cigarettes daily for 40 years. He has no history of diabetes mellitus or hypertension Ophthalmologic examination of the right eye shows a grayish discoloration of the macula with areas of adjacent hemorrhage.  Which of the following should be specifically targeted in treatment of this patient's condition?

A 22-year-old woman is brought to the emergency department because of a 2-day history of fever, intermittent rigors, and night sweats. She also has a 1-month history of progressive fatigue. Five weeks ago, she was hospitalized and received intravenous antibiotics for treatment of bacterial meningitis while visiting relatives in Guatemala. Her temperature is 39.4°C (102.9°F), pulse is 130/min, and blood pressure is 105/70 mm Hg. Examination shows pallor and scattered petechiae and ecchymoses. Laboratory studies show a hemoglobin concentration of 9.0 g/dL, a leukocyte count of 1100/mm3 with 30% segmented neutrophils, and a platelet count of 20,000/mm3. The patient was most likely treated with which of the following antibiotics?