Many patients undergoing ambulatory shoulder arthroscopy experience moderate to severe pain after surgery. Finding ways to minimize postoperative pain are ideal. Dexamethasone is a corticosteroid that is commonly used to prevent and/or treat nausea and inflammation. The addition of higher doses of dexamethasone to nerve blocks, which are injections of local anesthetics into the upper shoulder area, has been shown to prolong block duration and reduce pain. However, it is unclear whether the advantage of longer pain relief outweighs patient dissatisfaction with the prolonged feeling of a numb arm. Furthermore, recent studies have shown that systemic, intravenously administered dexamethasone may similarly reduce pain levels when compared with dexamethasone in the block. In our study, the investigators propose to examine the effect of low-dose IV versus block dexamethasone on interscalene block duration in patients undergoing shoulder arthroscopy. Most studies have used 4 mg or more. One study suggests that 1 mg may have the same effect as larger doses. Our aims are to determine whether the addition of low-dose dexamethasone to a local anesthetic in the block can prolong its duration, and whether there are differences in postoperative pain, consumption of painkillers, side effects, and satisfaction in patients who received IV or block dexamethasone. Patients (128 total) will be randomly assigned to either receive IV or block dexamethasone, and postoperative assessments (pain, painkiller use, side effects, block duration, satisfaction, complications) will be made via phone at 2, 3, 4 (if needed), and 7-10 days after surgery. Results from this study will reveal whether patients prefer the longer-duration analgesia that may be obtained with low-dose dexamethasone in the block.