A 62-year-old man with congestive heart failure has been taking a loop diuretic to reduce peripheral edema. His labs reveal a serum potassium of 3.1 mEq/L, so a potassium-sparing diuretic, triamterene, is added to his regimen. Which of the following is the site of action of this agent?

A 62-year-old man with congestive heart failure has been taking a loop diuretic to reduce peripheral edema. His labs reveal a serum potassium of 3.1 mEq/L, so a potassium-sparing diuretic, triamterene, is added to his regimen. Which of the following is the site of action of this agent?

A 42-year-old woman with irritable bowel syndrome with diarrhea predominance presents to her primary care physician for treatment. The physician suggests an exercise regimen, dietary modifications, and a bulk laxative. The likely mechanism of action of this agent would involve which of the following?

A 43-year-old woman with recurrent urinary tract infections who is usually sensitive to ciprofloxacin now has three consecutive UTIs in a 4-month period. Each time, the culture and sensitivity reveal resistance to ciprofloxacin. What is the most likely source of resistance?

A 16-year-old boy with cystic fibrosis undergoes many types of treatments intended to loosen and thin the mucus obstructing his airways in order for him to expel it. He also takes an oral pancreatic enzyme because his pancreas is unable to secrete sufficient amounts because of mucus obstruction. Which of the following medications thins cystic fibrosis mucus by cleaving extracellular DNA?

A 34-year-old construction worker injured his right leg while on the job. His medical history includes poorly controlled Type-2 diabetes mellitus. He now presents with cellulitis in his right leg, for which he is given empiric IV vancomycin. He also complains of nausea, for which he is given an antiemetic. Which of the following antiemetics is also an antihistamine?