Can Thyronorm (levothyroxine) be given to a patient on the day of surgery?

Management of Thyronorm (Levothyroxine) on the Day of Surgery

Thyronorm (levothyroxine) should be continued and administered on the morning of surgery as it does not increase surgical risks and maintaining consistent thyroid hormone levels is important for patient outcomes. 1

Rationale for Continuing Levothyroxine During Surgery

• Levothyroxine is a thyroid hormone replacement medication that should be maintained at consistent levels to avoid fluctuations in thyroid hormone status 1
• Unlike medications that may increase bleeding risk or interfere with anesthesia, levothyroxine does not need to be held before surgery 1
• Interrupting levothyroxine therapy could lead to rising TSH levels, which is particularly undesirable in thyroid cancer management 1
• The FDA label for levothyroxine does not list surgery as a contraindication for continuing the medication 2

Clinical Considerations

• Patients should notify their physician or dentist that they are taking levothyroxine prior to any surgery, but this is for awareness rather than discontinuation 2
• Hypothyroidism has historically been considered a contraindication to surgery, but modern evidence shows that the risks are manageable with proper perioperative care 3
• Maintaining consistent thyroid hormone levels helps avoid complications such as:
  • Intraoperative hypotension (more common in hypothyroid patients) 3
  • Postoperative gastrointestinal complications 3
  • Neuropsychiatric complications 3

Special Patient Populations

Thyroid Cancer Patients

• For patients with differentiated thyroid cancer, TSH suppression therapy is an important part of treatment 1
• In high-risk thyroid cancer patients, maintaining TSH suppression may decrease progression of metastatic disease 1
• TSH suppression (serum level <0.1 μIU/mL) is recommended for all thyroid cancer patients with persistent structural disease in the absence of specific contraindications 4

Post-Thyroidectomy Patients

• Postoperative levothyroxine is indicated for all thyroidectomy patients, with TSH kept in the normal range through appropriate dosing 1
• Dose requirements vary widely between patients (75-250 μg daily) and should be determined based on TSH and free T4 levels 5
• For patients who have undergone total thyroidectomy, the typical maintenance dose is approximately 1.5 μg/kg 6
• For patients who have undergone lobectomy, the typical maintenance dose is approximately 1.3 μg/kg 6

Potential Pitfalls and Caveats

• Abrupt discontinuation of levothyroxine before surgery can lead to hypothyroid symptoms and potentially complicate surgical recovery 5
• Body mass index (BMI) affects levothyroxine dosing requirements - patients with higher BMI often require lower weight-based dosing 7
• Bioequivalence sometimes differs among generic and brand name levothyroxine products, so patients should ideally continue with their established formulation perioperatively 5
• Laboratory assessment of thyroid function should not be performed until at least 6 weeks after any dose adjustment, as a new equilibrium takes time to establish 5

In conclusion, Thyronorm (levothyroxine) should be continued on the day of surgery to maintain consistent thyroid hormone levels and avoid potential complications associated with fluctuating thyroid status.