Is it safe to take Lasix (furosemide) on the day of surgery?

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Last updated: October 28, 2025View editorial policy

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Management of Furosemide (Lasix) on the Day of Surgery

It is safe to continue furosemide (Lasix) on the day of surgery for patients who chronically take this medication, as it does not significantly increase the risk of intraoperative hypotension. 1

Evidence-Based Recommendations

Safety Profile of Furosemide During Surgery

  • Randomized controlled trial evidence shows that administration of furosemide on the day of surgery in chronic users does not significantly increase the risk of intraoperative hypotension compared to placebo (49% vs 51.9%, RR 0.95) 1
  • There is no significant difference in the intraoperative administration of vasopressors or fluids between patients who take or withhold furosemide on the day of surgery 1
  • The risk of developing postoperative cardiovascular events is not significantly different between patients who continue furosemide (4.8%) or receive placebo (2.8%) on the day of surgery 1

Perioperative Medication Management Principles

  • Medication management should be based on the specific medication's risk profile, potential for withdrawal, and impact on surgical outcomes 2
  • Continuing medications where abrupt discontinuation could lead to withdrawal or disease exacerbation is generally recommended 2
  • For diuretics specifically, unlike SGLT2 inhibitors which should be discontinued 3-4 days before surgery 3, furosemide does not carry the same risks and can be continued 1

Clinical Considerations

Benefits of Continuing Furosemide

  • Maintaining fluid balance for patients who require chronic diuretic therapy 4
  • Avoiding potential fluid overload that could occur if the medication is withheld 4
  • Preventing potential rebound fluid retention that might occur with abrupt discontinuation 2

Special Populations

  • For patients undergoing day-case surgery, continuing chronic medications that don't increase surgical risk is generally recommended to maintain physiological stability 3
  • For patients with heart failure or hypertension, continuing medications that control these conditions is important for perioperative hemodynamic stability 3

Common Pitfalls to Avoid

  • Unnecessarily withholding furosemide may lead to fluid retention and potential complications in patients who require chronic diuretic therapy 2
  • Assuming all diuretics carry the same risk profile - unlike SGLT2 inhibitors which should be discontinued before surgery 3, furosemide has been shown to be safe when continued 1
  • Failing to monitor electrolytes postoperatively, as furosemide can affect potassium levels even though studies show no significant difference in electrolyte abnormalities between continuation and withholding 1

In conclusion, based on the highest quality evidence from a randomized controlled trial, furosemide can be safely continued on the day of surgery for patients who chronically take this medication, as it does not significantly increase the risk of intraoperative hypotension or other adverse outcomes.

References

Guideline

Perioperative Medication Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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