Pharmacology Quiz on Drug Mechanisms

USMLE Step 1 Sample Test Questions

• Item 1: A 67-year-old woman with a bicuspid aortic valve is admitted with fever and chills. Blood cultures show viridans streptococci susceptible to penicillin. An additional antibiotic is given that is synergistic with penicillin to shorten treatment. The likely mechanism of action of the additional antibiotic is inhibiting DNA gyrase.

• Item 2: A 12-year-old girl presents with jaundice. Total bilirubin is 3 mg/dL, direct component is 1 mg/dL. Haptoglobin, AST, and ALT are normal. The most likely additional finding is decreased UDP glucuronosyltransferase activity.

• Item 3: Drug X is added to a muscle bath containing guinea pig intestinal smooth muscle. The table shows the effects of various agonists on muscle tension before and after drug X. The drug X most likely belongs to a class of drugs like a1-adrenergic antagonists.

• Item 4: A 30-year-old woman at 28 weeks' gestation is given Rho(D) immune globulin. The treatment is most likely to prevent the development of RhD antibodies.

• Item 5: A 55-year-old man with hypertension and chronic kidney disease has shortness of breath and confusion. His ECG shows low voltage with electrical alternans. The most likely physical finding is increased jugular venous pressure and increased pulsus paradoxus.

• Item 6: A 52-year-old woman with type 2 diabetes mellitus begins pharmacotherapy. Four weeks later, her hepatic glucose output is decreased, and target tissue glucose uptake and utilization increase. The most likely prescribed drug is Metformin.

• Item 7: An asymptomatic 44-year-old man has HIV infection. A complete blood count shows 10 g/dL hemoglobin, 30% hematocrit, 4600/mm³ leukocytes, 15,000/mm³ platelets. Petechiae, likely, is the most likely physical finding.

• Item 8: A 23-year-old woman with bone marrow failure is treated with rabbit antithymocyte globulin. Ten days later, she develops fever, lymphadenopathy, arthralgias, and erythema on her hands and feet. The most likely cause is cytokine secretion by natural killer cells.

• Item 9: A 42-year-old woman with a perforated small bowel, facial fracture repair, and femur fixation is awake but not fully alert. She's receiving intravenous morphine via a patient-controlled pump. The physician should switch the patient to oral acetaminophen since she is able to take medication orally.

• Item 10: A 22-year-old woman presents with an itchy, red rash on her right forearm. She uses a new hair dye recently. The most likely ligand-receptor pair that played a primary role in the skin rash is CD28 on T lymphocytes and CD80 on epidermal Langerhans cells.

• Item 11: A study of muscle metabolism during hyperglycemia and hyperinsulinemia measured malonyl-CoA concentrations. Increased malonyl-CoA most likely directly inhibits fatty acid oxidation.

• Item 12: A study of chronic myeloid leukemia in blast crisis uses a tyrosine kinase inhibitor at increasing dose cohorts. The best description of this study is an open-labeled clinical trial.

• Item 13: A 63-year-old man has left leg pain and swelling. A 1-month history of back pain. Weight loss despite normal appetite. The most likely cause is hypercoagulability from advanced malignancy.

• Item 14: A 40-year-old woman presents with increased facial hair growth. Her last menstrual period was four months ago. Her serum testosterone is increased and ultrasonography shows a 12-cm ovarian mass. The most likely diagnosis is Sertoli-Leydig tumor.

• Item 15: A 35-year-old man presents with pain and swelling in his right arm after a scrape. Examination shows edema around a fluctuant erythematous lesion. The primary mechanism of edema is separation of endothelial junctions.

• Item 16: A 12-year-old boy presents with headaches, nausea, and vomiting. Fundoscopic examination shows bilateral papilledema. An MRI shows a tumor in the pineal region compressing the brain stem. The most likely impaired oculomotor function is the vestibulo-ocular reflex.

• Item 17: A 52-year-old male has nausea, vomiting, and right-sided abdominal pain radiating to his back. Past medical history includes diabetes, hyperlipidemia, and atrial fibrillation. The most likely predisposing risk factor is past smoking history.

• Item 18: A 24-year-old man has a red, itchy rash on his buttocks and legs after returning from a cruise to the Caribbean. Physical examination shows the findings seen in the photograph. The most likely location where the infectious agent proliferated is the hair follicle.

• Item 19: A 45-year-old man with epigastric heartburn and weight loss presents with positive stool occult blood test and endoscopy showing a bleeding 3-cm ulcer. The most likely process involved in this case is elaborating of proteases and urease with local tissue destruction.

• Item 20: A 14-year-old male is hit on the lateral side of his leg just below his knee. He is unable to dorsiflex his foot. The most likely injured nerve is common fibular nerve (peroneal).

• Item 21: A 26-year-old woman has severe back and abdominal pain, and vaginal bleeding. The fluid from the rapture will most likely be found in the pouch of douglas.

• and so on...

Test your understanding of pharmacology with this quiz focusing on mechanisms of action of antibiotics, drug effects, and clinical findings in patients. Each question challenges you to apply your knowledge to real-world scenarios in medicine. Suitable for students studying pharmacology or related fields.