Antiparasitic drugs (antiprotozoals) — MCQs

An 87-year-old male nursing home resident is currently undergoing antibiotic therapy for the treatment of a decubitus ulcer. One week into the treatment course, he experiences several episodes of watery diarrhea. Subsequent sigmoidoscopy demonstrates the presence of diffuse yellow plaques on the mucosa of the sigmoid colon. Which of the following is the best choice of treatment for this patient?

You are seeing a patient in clinic who recently started treatment for active tuberculosis. The patient is currently being treated with rifampin, isoniazid, pyrazinamide, and ethambutol. The patient is not used to taking medicines and is very concerned about side effects. Specifically regarding the carbohydrate polymerization inhibiting medication, which of the following is a known side effect?

A 31-year-old male traveler in Thailand experiences fever, headache, and excessive sweating every 48 hours. Peripheral blood smear shows trophozoites and schizonts indicative of Plasmodia infection. The patient is given chloroquine and primaquine. Primaquine targets which of the following Plasmodia forms:

A 24-year-old woman comes to the emergency department because of a 4-hour history of headaches, nausea, and vomiting. During this time, she has also had recurrent dizziness and palpitations. The symptoms started while she was at a friend's birthday party, where she had one beer. One week ago, the patient was diagnosed with a genitourinary infection and started on antimicrobial therapy. She has no history of major medical illness. Her pulse is 106/min and blood pressure is 102/73 mm Hg. Physical examination shows facial flushing and profuse sweating. The patient is most likely experiencing adverse effects caused by treatment for an infection with which of the following pathogens?

A 31-year-old woman presents to your office with one week of recurrent fevers. The highest temperature she recorded was 101°F (38.3°C). She recently returned from a trip to Nigeria to visit family and recalls a painful bite on her right forearm at that time. Her medical history is significant for two malarial infections as a child. She is not taking any medications. On physical examination, her temperature is 102.2°F (39°C), blood pressure is 122/80 mmHg, pulse is 80/min, respirations are 18/min, and pulse oximetry is 99% on room air. She has bilateral cervical lymphadenopathy and a visible, enlarged, mobile posterior cervical node. Cardiopulmonary and abdominal examinations are unremarkable. She has an erythematous induration on her right forearm. The most likely cause of this patient's symptoms can be treated with which of the following medications?

A 26-year-old student arrives to student health for persistent diarrhea. She states that for the past 2 months she has had foul-smelling diarrhea and abdominal cramping. She also reports increased bloating, flatulence, and an unintentional 4 lb weight loss. Prior to 2 months ago, she had never felt these symptoms before. She denies other extra-gastrointestinal symptoms. The patient is an avid hiker and says her symptoms have caused her to miss recent camping trips. The patient has tried to add more fiber to her diet without relief. She feels her symptoms worsen with milk or cheese. Her medical history is insignificant and she takes no medications. She drinks whiskey socially, but denies smoking tobacco or using any illicit drugs. She is sexually active with her boyfriend of 2 years. She went to Mexico 6 months ago and her last multi-day backpacking trek was about 3 months ago in Vermont. Physical examination is unremarkable. A stool sample is negative for fecal occult blood. Which of the following is an associated adverse effect of the most likely treatment given to manage the patient’s symptoms?

An experimental drug, ES 62, is being studied. It prohibits the growth of vancomycin-resistant Staphylococcus aureus. It is highly lipid-soluble. The experimental design is dependent on a certain plasma concentration of the drug. The target plasma concentration is 100 mmol/dL. Which of the following factors is most important for calculating the appropriate loading dose?

A 52-year-old man presents for a routine checkup. Past medical history is remarkable for stage 1 systemic hypertension and hepatitis A infection diagnosed 10 years ago. He takes aspirin, rosuvastatin, enalapril daily, and a magnesium supplement every once in a while. He is planning to visit Ecuador for a week-long vacation and is concerned about malaria prophylaxis before his travel. The physician advised taking 1 primaquine pill every day while he is there and for 7 consecutive days after leaving Ecuador. On the third day of his trip, the patient develops an acute onset headache, dizziness, shortness of breath, and fingertips and toes turning blue. His blood pressure is 135/80 mm Hg, heart rate is 94/min, respiratory rate is 22/min, temperature is 36.9℃ (98.4℉), and blood oxygen saturation is 97% in room air. While drawing blood for his laboratory workup, the nurse notes that his blood has a chocolate brown color. Which of the following statements best describes the etiology of this patient’s most likely condition?

A 65-year-old male with diffuse large B cell lymphoma is treated with a chemotherapy regimen including 6-mercaptopurine. Administration of which of the following agents would increase this patient’s risk for mercaptopurine toxicity?

A 25-year-old woman presented to an urgent care center with a complaint of a cough for more than 3 weeks that was accompanied by night sweats, weight loss, and malaise. On physical examination, the patient had slightly pale palpebral conjunctivae, bilateral posterior cervical lymphadenopathy, but with no adventitious breath sounds in the lung fields bilaterally. The remainder of the physical examination was routine. The patient was started on a drug regimen that was to be taken for 6 months. On follow-up after 2 months, the ALT and AST levels were elevated. Which of the following anti-tubercular drugs could have contributed to this laboratory result?