Which of the following is a common side effect of corticosteroids?

Moon facies is a common side effect of corticosteroids due to the medication's impact on fat distribution and metabolism. Corticosteroids can cause the body to retain fluid and alter how fat is stored. This can lead to a characteristic rounding of the face, often referred to as "moon facies," which is notably present in patients who are on long-term corticosteroid therapy. This side effect arises from the increased deposition of adipose tissue in the facial area, a phenomenon related to changes induced by glucocorticoids in various metabolic pathways.

In contrast, weight loss, decreased appetite, and bradycardia are not commonly associated with corticosteroid use. Steroids typically lead to weight gain and increased appetite, making them less likely candidates for common side effects. Bradycardia, or slow heart rate, is also not a direct effect of corticosteroids and is more often related to other factors or medications. Therefore, moon facies accurately represents a typical and recognizable side effect of corticosteroid therapy.