The investigators are performing this study to determine if supplementation with calcium and calcitriol (vitamin D) before surgery decreases the rate of hypocalcemia (low calcium) after surgery.

Postoperative hypocalcemia (low calcium) is the most common complication after thyroidectomy. Symptoms range from numbness/tingling around the mouth and fingers to severe problems such as low blood pressure, irregular heartbeat, muscle cramps and uncontrollable muscle spasms.

The current standard of practice at Lahey for patients undergoing total thyroidectomy is to start Tums 1500mg three times daily and Calcitriol 0.25mcg twice daily immediately after surgery. Also current practice is for each patient to have their calcium and albumin levels checked at 8 hours and 24 hours after surgery. If the corrected calcium level drops below 8.5 or they exhibit symptoms of hypocalcemia the dose of the Tums and Calcitriol are increased per protocol. All patients must also follow up in 3-4 days to have their calcium and albumin levels rechecked.

The investigators propose to change the above standard practice at Lahey by making only one change. The investigators wish to start Tums and Calcitriol 5 days before surgery, as opposed to after surgery. This will be the only change to the current standard of care at Lahey.

The investigators hypothesize that initiating Tums and Calcitriol supplementation in the preoperative period will decrease the overall rate of postoperative hypocalcemia and its related symptoms. This will possibly decrease length of hospital stay, decrease cost, and prevent any serious complications associated with low calcium.

The main objective of this study is to determine if treating patients with calcitriol and calcium prior to thyroidectomy decreases postoperative hypocalcemia. The primary outcome to be measured is clinical hypocalcemia, defined as peri-oral numbness and/or tingling, numbness and/or tingling in fingers, tetany, seizures, hypotension, palpitations. A secondary outcome measure of biochemical hypocalcemia will be measured. Biochemical hypocalcemia will be defined as a corrected calcium for albumin of less than 8.5 at 8 hours, 1 day, and 3 days postoperatively. Additional secondary outcome measures will be hospital length of stay, need for calcium gluconate IV supplementation, need for additional calcium monitoring.

Postoperative hypocalcemia is the most common complication after thyroidectomy. Symptoms range from perioral numbness/tingling and tingling in fingers to severe complications such as hypotension, arrhythmias and tetany. In prior studies hypocalcemia after thyroidectomy can occur up to 50% of the time. A retrospective cohort study from 2017 shows that treating patients with vitamin D and calcium preoperatively decreases the rate of postoperative hypocalcemia. Preoperative treatment in that study included calcitriol 0.25mcg PO BID and Tums 1,500mg PO TID starting 5 days before surgery. This showed a significant decrease in postoperative hypocalcemia, decreased hospital stay, and overall decrease in cost for patients undergoing total thyroidectomy. This study was limited by its retrospective and observational nature. By performing a prospective randomized study on preoperative supplementation the investigators hope to provide a stronger level of evidence to support this practice.

Inclusion Criteria:

• All patients, age >18, undergoing total thyroidectomy are eligible.

Exclusion Criteria:

• partial thyroidectomy, lobectomy, or concurrent parathyroidectomy.

Data will be managed by Co-investigators on a secure spread sheet in a password protected folder on the Lahey General Surgery shared drive. Subjects will be assigned a number and there will be no identifying information on this spreadsheet.