What is the most likely adverse effect after administering dexamethasone (Decadron), 10mg?

Dexamethasone is a corticosteroid that can cause various metabolic effects due to its influence on glucose metabolism and response to stress. One of the notable adverse effects associated with the administration of dexamethasone, especially at a dose of 10 mg, is hyperglycemia. This occurs because corticosteroids can increase gluconeogenesis and decrease glucose uptake by tissues, leading to elevated blood sugar levels.

This effect is particularly pronounced in individuals who may already be predisposed to diabetes or have underlying insulin resistance. The risk can be further increased with higher doses or in patients taking corticosteroids for extended periods.

While the other options can also be associated with corticosteroid use, hyperglycemia is a common and well-documented response to glucocorticoid therapy, making it the most likely adverse effect in this context. Akathisia, hypertension, and tachycardia could occur but are less directly linked to the administration of dexamethasone compared to hyperglycemia.