A 37-year-old man is found to have hypercholesterolemia during a routine checkup. The physician prescribes lovastatin and counsels the patient to make healthy dietary and lifestyle changes to keep his cholesterol under control. Two months later, he returns for a follow-up visit, and the physician discovers his LDL level remains virtually unchanged. He insists that he is taking the medication exactly as prescribed. The physician knows lovastatin is metabolized by the cytochrome P450 3A4. What else may he be using that would explain his condition?

A 37-year-old man is found to have hypercholesterolemia during a routine checkup. The physician prescribes lovastatin and counsels the patient to make healthy dietary and lifestyle changes to keep his cholesterol under control. Two months later, he returns for a follow-up visit, and the physician discovers his LDL level remains virtually unchanged. He insists that he is taking the medication exactly as prescribed. The physician knows lovastatin is metabolized by the cytochrome P450 3A4. What else may he be using that would explain his condition?

A 76-year-old man presents to the clinic for follow-up of his benign prostatic hyperplasia. He has been doing well with his symptoms since starting finasteride. He no longer has as much difficulty starting his stream and feels that he empties his bladder completely. What is the mechanism of action of finasteride?

A 23-year-old woman presents to her primary care physician with an enlarging neck mass and weight loss. The large mass is seen in the midline of the neck. She has lost 15lb over the past month, feels like her heart is racing, and is always hot. The patient is diagnosed with Graves' disease and started on propylthiouracil. Which of the following is a side effect of propylthiouracil?

A 54-year-old man with elevated cholesterol levels is treated with niacin. Within 2 weeks of starting therapy, he develops an uncomfortable feeling of warmth and itchiness. Which of the following is the most appropriate next step in the management of this patient?

A young married couple complains of being unable to conceive after 9 months of unprotected sex. The wife has normal TSH and FSH levels and a normal pelvic exam. They agree to a trial of letrozole to see if they can increase their fecundity. How does letrozole work?