Should Metformin (metformin) or Atenolol (atenolol) be discontinued one day prior to surgery?

From the Guidelines

Metformin should be held on the day of surgery, while atenolol should be continued through the perioperative period. This approach is based on the most recent guidelines, which prioritize the management of diabetes and cardiovascular risk in the perioperative period 1. The decision to hold metformin is due to the risk of lactic acidosis, particularly if the patient develops acute kidney injury or receives contrast agents during the procedure. In contrast, beta-blockers like atenolol should be continued without interruption through surgery to prevent withdrawal symptoms that can lead to rebound tachycardia, hypertension, and increased risk of perioperative cardiac events. Abrupt discontinuation of beta-blockers can increase the risk of myocardial ischemia and mortality, as supported by studies such as the 2009 ACCF/AHA focused update on perioperative beta blockade 1. For patients on atenolol, the usual dose should be taken on the morning of surgery with a small sip of water.

Some key points to consider in the perioperative management of patients on metformin and atenolol include:

• Target glucose range for the perioperative period should be 100–180 mg/dL (5.6–10.0 mmol/L) 1
• Perform a preoperative risk assessment for patients at high risk for ischemic heart disease and those with autonomic neuropathy or renal failure 1
• Monitor blood glucose at least every 2–4 h while the individual takes nothing by mouth and dose with short- or rapid-acting insulin as needed 1
• Stricter perioperative glycemic goals are not advised, as they may not improve outcomes and are associated with more hypoglycemia 1

Always consult with the surgical team and anesthesiologist for patient-specific recommendations, as individual circumstances may warrant different approaches.

From the FDA Drug Label

Surgery and other procedures —Withholding of food and fluids during surgical or other procedures may increase the risk for volume depletion, hypotension, and renal impairment. Metformin hydrochloride tablets should be temporarily discontinued while patients have restricted food and fluid intake Major Surgery Chronically administered beta-blocking therapy should not be routinely withdrawn prior to major surgery, however, the impaired ability of the heart to respond to reflex adrenergic stimuli may augment the risks of general anesthesia and surgical procedures.

Metformin should be temporarily discontinued while patients have restricted food and fluid intake, but the label does not specify the exact timing of discontinuation. Atenolol should not be routinely withdrawn prior to major surgery. No specific recommendation is given for stopping Metformin or Atenolol one day prior to surgery. 2 3

From the Research

Metformin and Surgery

• The provided studies do not directly address whether Metformin should be stopped one day prior to surgery 4, 5, 6, 7, 8.
• However, the studies discuss the relationship between Metformin and contrast medium administration, which may be relevant to surgical procedures involving contrast media.
• According to the studies, there is no evidence that continuing Metformin during contrast medium administration is associated with a higher risk of contrast-induced acute kidney injury (CI-AKI), lactic acidosis, or renal function deterioration compared to patients who discontinued Metformin or who were not Metformin users 4, 8.
• Some studies suggest that Metformin can be continued in patients with normal renal function, but it may need to be withheld in patients with decreased renal function or after contrast medium administration if renal failure occurs 5, 7.

Atenolol and Surgery

• There is no information provided in the studies about Atenolol and its relationship to surgery or contrast medium administration.
• Therefore, it is not possible to determine whether Atenolol should be stopped one day prior to surgery based on the provided evidence.

General Considerations

• The decision to stop or continue any medication, including Metformin or Atenolol, before surgery should be made on a case-by-case basis, taking into account the individual patient's medical history, renal function, and other relevant factors.
• It is essential to consult with a healthcare professional to determine the best course of action for each patient 4, 5, 6, 7, 8.