08. Procedures – Pre-Op Medication Adjustments

Several medications require careful consideration before surgery due to their effects on bleeding, healing, or other perioperative complications. Here’s a list of common medications that may need to be stopped or adjusted:

  1. Antiplatelet Agents
    • Aspirin, Clopidogrel, Prasugrel, Ticagrelor.
    • Usually stopped 5-7 days before surgery to reduce the risk of bleeding, but this depends on the type of surgery and the patient’s cardiovascular risk.
  2. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
    • Ibuprofen, Naproxen, and others.
    • Typically stopped several days before surgery due to increased bleeding risk.
  3. Diabetes Medications
    • Metformin is usually withheld 24-48 hours before surgery to reduce the risk of lactic acidosis, especially in procedures involving contrast media or anticipated prolonged fasting.
    • SGLT2s are withheld 24 hours before due to the risk of euglycemic ketoacidosis
    • Insulin regimens will need adjustment to prevent hypoglycemia, especially during periods of fasting.
      1. Long-acting insulin is reduced to ~ 50%
      2. Short-acting insulin is withheld
  4. Antihypertensives
    • ACE inhibitors and ARBs are often withheld on the morning of surgery due to the risk of hypotension.
    • Other antihypertensives are typically continued to avoid rebound hypertension.
  5. Diuretics
    • May be withheld on the morning of surgery to avoid electrolyte imbalances and dehydration.
  6. Selective Serotonin Reuptake Inhibitors (SSRIs)
    • May increase the risk of bleeding, especially in combination with other anticoagulants, but stopping them can risk withdrawal or relapse of psychiatric symptoms.
  7. Monoamine Oxidase Inhibitors (MAOIs)
    • Can interact with anesthetics and other medications used during surgery, often requiring discontinuation.
  8. Herbal Supplements and Vitamins
    • Products like Ginkgo biloba, Ginseng, Garlic, Vitamin E, and others can affect bleeding and interact with anesthetics.
  9. Anticoagulants
    • Warfarin is generally stopped 5-7 days before to surgery
    • NOACs are stopped 24-48-72 hours before surgery
    • Bridging with LMWH can be used
  10. Glucocorticoids
    • Chronic steroid use can affect wound healing and stress response.
    • Patients on long-term steroids may need supplemental doses perioperatively.
  11. Thyroid Hormone Replacement
    • Generally continued as usual
  12. Immunosuppressants
    • Cyclosporine, Tacrolimus, or Biologics used for autoimmune diseases or organ transplants, may need adjustment to balance the risk of infection and rejection.

Important Considerations

  • Risk vs. Benefit
    • The decision to stop any medication should weigh the risks of stopping (e.g., thrombosis, hypertension, psychiatric relapse) against the risks of continuing (e.g., bleeding, interactions).
  • Procedure-Specific Risks
    • The type of surgery (e.g., orthopedic, cardiovascular, neurosurgery) may dictate specific risks and medication adjustments.
  • Consultation
    • Coordination between GP, surgeon, and relevant specialists (e.g., cardiologist, endocrinologist) to develop a perioperative plan.
  • Patient Education
    • Inform the patient about any medication changes, the reasons for them, and the plan for restarting medications post-surgery.

Each patient’s medication regimen and health status are unique, so a personalized approach is essential in perioperative medication management.

Warfarin and NOACs

Patients on anticoagulants such as Warfarin or Non-Vitamin K Oral Anticoagulants (NOACs) require careful pre-operative management to balance the risk of thrombosis against the risk of surgical bleeding. Here’s a general overview of the considerations for pre-operative medication changes in these patients:

1. Warfarin:

  • Assessment: Assess the patient’s risk of thromboembolism versus the risk of bleeding associated with the surgery.
  • Management: Generally, Warfarin is stopped 5 days before surgery to allow the INR (International Normalized Ratio) to normalize.
  • Bridging Therapy: For patients at high risk of thromboembolism, consider bridging anticoagulation with short-acting agents like low molecular weight heparin (LMWH). Bridging is typically started when the INR falls below a therapeutic range.
  • Resumption Post-Op: Warfarin is usually resumed 12-24 hours post-surgery, once hemostasis is established with bridging anticoagulation continued until the INR is therapeutic.

2. Non-Vitamin K Oral Anticoagulants (NOACs):

  • Types: Include Rivaroxaban, Apixaban, Dabigatran
  • Management: The timing of discontinuation depends on the specific NOAC, the patient’s renal function, and the bleeding risk of the surgery.
    • For low bleeding risk procedures, NOACs are generally stopped 24-48 hours before surgery.
    • For high bleeding risk procedures, they are typically stopped 48-72 hours before surgery.
  • Bridging Therapy: Usually not required due to the short half-life of these medications.
  • Resumption Post-Op: NOACs can often be restarted relatively soon after surgery (usually within 24-48 hours) provided that adequate hemostasis has been achieved.

General Considerations:

  • Pre-Op Assessment: Comprehensive assessment of the patient’s medical history, including the reason for anticoagulation, is crucial.
  • Communication: Coordinate with the patient’s cardiologist or physician.
  • Risk Stratification: Consider both the risk of thromboembolism and the risk of surgical bleeding.
  • Renal Function: For NOACs, renal function is an important consideration due to their renal excretion.
  • Urgent Surgery: If urgent surgery is required, reversing the effects of anticoagulants (e.g., using Vitamin K for Warfarin or specific reversal agents for NOACs) may be necessary.

Patient Education:

  • Inform the patient about the importance of stopping anticoagulants preoperatively and the plan for resuming them postoperatively.
  • Discuss the signs of bleeding or thrombosis to look out for during the perioperative period.

Diabetes

Patients with diabetes who are undergoing surgery require special consideration regarding their medication management to avoid complications like hyperglycemia or hypoglycemia. Here’s a general guide on pre-operative medication changes for diabetics:

  • Insulin:
    • Type 1 Diabetes: Patients should not stop their insulin. However, the dose may need adjustment. On the day of surgery, typically, half of the usual long-acting insulin dose is recommended. Short-acting insulins are often with held or significantly reduced.
    • Type 2 Diabetes: For those on basal insulin, a reduced dose (often 50-75% of the usual dose) may be given on the morning of surgery. Bolus insulins are usually withheld on the day of surgery.
  • Oral Hypoglycemics:
    • Metformin: Discontinued 24-48 hours before surgery to reduce the risk of lactic acidosis, especially in procedures involving contrast media or anticipated prolonged fasting.
    • Sulfonylureas (e.g., Glibenclamide, Glipizide): Usually withheld on the day of surgery to avoid hypoglycemia, as these drugs increase insulin secretion.
    • DPP-4 Inhibitors (e.g., Sitagliptin): Generally safe but often withheld on the day of surgery to reduce the risk of hypoglycemia.
    • SGLT2 Inhibitors (e.g., Empagliflozin): Discontinued at least 24 hours before surgery due to the risk of euglycemic ketoacidosis, especially in procedures involving fasting or fluid restrictions.
    • GLP-1 Receptor Agonists: Typically withheld on the day of surgery (or earlier) due to gastrointestinal side effects that can complicate surgical procedures.
  • Adjustments for Minor vs. Major Surgery:
    • For minor surgeries with short fasting times, adjustments might be minor.
    • Major surgeries or those requiring prolonged fasting may need more significant adjustments.
  • Blood Glucose Monitoring:
    • Increased monitoring before and after surgery is crucial to manage blood glucose levels effectively.
  • Postoperative Considerations:
    • Resume usual diabetes medications once the patient is eating and drinking normally.
    • Closely monitor blood glucose levels postoperatively.
  • Special Situations:
    • Consider consulting with an endocrinologist for patients with complex diabetic regimens or those with poorly controlled diabetes.
  • Patient Education:
    • Ensure patients understand the changes in their diabetes management and the importance of blood glucose monitoring during the perioperative period.