A 55 year-old male comes to your office for the management of hypertension, chronic heart failure and type 2 diabetes mellitus. His current medications include spironolactone, metformin, metoprolol and furosemide. While you discuss spironolactone, he asks you about the common side effects of spironolactone he should be aware of. Which of the following common side effects is associated with spironolactone?