Q. A 25-year-old man goes on a hiking trip to a high altitude area. On the first night, he begins to experience symptoms of altitude sickness, including a headache, nausea, and difficulty sleeping. He also notices that he is having to wake up frequently to urinate. The next morning, he visits the nearby clinic and is prescribed acetazolamide. He takes the medication as directed and within a few hours, his symptoms begin to improve. Which of the following is a side effect of acetazolamide when used to treat altitude sickness?