Pharmacy PEBC Practice Exam

Question: 1 / 20

PB is a 70 year old female who is on the final day of a 10-day course of cotrimoxazole DS, i po bid for mild pyelonephritis. PB’s medical conditions include hypertension and osteoarthritis, for which she takes enalapril 5 mg po bid and acetaminophen 650 mg po qid. PB has been feeling unwell for the past two days, complaining of abdominal pain, diarrhea, and muscle weakness. She presents to the emergency department, where it is discovered that her serum potassium level is 5.9 mmol/L (normal: 3.5-5.0 mmol/L) and her estimated creatinine clearance is 70 mL/min. What drug therapy problem is PB currently experiencing?

Her dosage of cotrimoxazole is too low.

Her dosage of cotrimoxazole is too high.

She is experiencing a drug interaction between enalapril and cotrimoxazole

PB is currently experiencing a drug interaction between enalapril, which is used to treat hypertension, and cotrimoxazole, which is used to treat pyelonephritis. This interaction can lead to an increase in potassium levels in the blood, as seen in PB's case with her elevated serum potassium level of 5.9 mmol/L. The other options, A and B, are incorrect because they do not address the drug interaction and instead focus on the dosage of cotrimoxazole being either too low or too high. Option D is incorrect because there is no known interaction between acetaminophen and cotrimoxazole. Therefore, the correct answer is C PB is experiencing a drug interaction between enalapril and cotrimoxazole.

She is experiencing a drug interaction between acetaminophen and cotrimoxazole.