What are the pre‑operative guidelines for continuing atenolol (beta‑blocker) on the day of surgery, including monitoring and criteria for withholding the dose?

Preoperative Atenolol Management on Day of Surgery

Patients already taking atenolol should continue their medication on the morning of surgery, as abrupt discontinuation increases risk of myocardial infarction, severe angina exacerbation, and ventricular arrhythmias. 1

Core Recommendation

Beta-blockers like atenolol must be continued through the perioperative period in patients on stable doses. 1 The 2024 ACC/AHA guidelines provide a Class I (strongest) recommendation for continuation based on clinical circumstances. This represents a fundamental shift from initiating beta-blockers for perioperative risk reduction to maintaining them in patients with established indications.

Critical Safety Considerations

Absolute Contraindications to Giving Atenolol Day of Surgery

Withhold the morning dose if:

• Heart rate <50 beats/min 2
• Systolic blood pressure <90 mmHg
• Second or third-degree heart block without pacemaker 3
• Acute decompensated heart failure requiring >80 mg IV furosemide 3
• Active bronchospasm in patients with asthma/COPD 3

Monitoring Requirements

Monitor these parameters before administering the morning dose:

• Heart rate - target >55 bpm
• Blood pressure - ensure systolic >100 mmHg
• Volume status - assess for hypovolemia which increases hypotension risk
• Cardiac rhythm - check for new conduction abnormalities

Dosing Strategy

Give the patient's usual morning dose with a small sip of water 2-4 hours before surgery. 3 Do not increase or decrease the dose on the day of surgery. For patients on twice-daily dosing, give only the morning dose.

Typical maintenance doses:

• Hypertension: 50-100 mg once daily 3
• Angina: 50-200 mg once daily 3
• Post-MI: 50-100 mg once daily 3

Why Continuation is Critical

Withdrawal syndrome is dangerous. Abrupt discontinuation causes:

• Severe angina exacerbation 3
• Acute myocardial infarction 3
• Ventricular arrhythmias 3
• Rebound hypertension

The FDA label explicitly warns that "patients with coronary artery disease should be advised against abrupt discontinuation of therapy." 3 This risk exists even in patients treated only for hypertension, as coronary disease may be unrecognized. 3

Evidence Base

The 2014 ACC/AHA systematic review 2 analyzed multiple trials showing that early studies suggesting benefit from perioperative beta-blockers may have actually demonstrated harm from withdrawal in control groups. The landmark POISE trial 2 demonstrated that initiating beta-blockers on the day of surgery increases mortality (Class III Harm recommendation). 1

However, continuing established therapy is fundamentally different from acute initiation. 1 The 2024 guidelines emphasize this distinction with a Class I recommendation for continuation versus a Class III Harm recommendation for same-day initiation. 1

Postoperative Management

Resume atenolol as soon as oral intake is tolerated, typically within 6-24 hours postoperatively. 3 If oral administration is not possible:

• Consider IV atenolol 5 mg over 5 minutes, may repeat once after 10 minutes 3
• Alternative: switch to IV metoprolol or esmolol infusion
• Do not skip doses - use IV route if necessary to avoid withdrawal

Special Populations

Renal Impairment

Atenolol is renally excreted. 3 For creatinine clearance:

• 15-35 mL/min: Maximum 50 mg daily 3
• <15 mL/min: Maximum 25 mg daily 3
• Hemodialysis: Give 25-50 mg after dialysis under supervision 3

Elderly Patients

Start with lower doses (25 mg) if initiating therapy, but continue established doses on day of surgery. 3 Elderly patients have decreased renal function and may require dose adjustment, but this should be done well before surgery, not on the day of procedure.

Common Pitfalls to Avoid

1. Do not hold beta-blockers "to be safe" - withdrawal is more dangerous than continuation 1, 3
2. Do not start atenolol on day of surgery - this increases mortality 1
3. Do not give with calcium channel blockers (verapamil/diltiazem) without careful monitoring - risk of severe bradycardia and heart block 3
4. Do not assume hypotension means the drug should be held - assess volume status first; hypovolemia is often the culprit
5. Do not forget to document the plan - ensure surgical and anesthesia teams know the patient took their beta-blocker

Intraoperative Considerations

Anesthesiologists should be informed that the patient took atenolol, as:

• Impaired reflex tachycardia response to hypovolemia or anesthetic agents 3
• May require direct-acting vasopressors (phenylephrine, vasopressin) rather than indirect agents 3
• Increased sensitivity to anesthetic agents - may need dose reduction
• Have epinephrine available for severe bradycardia or hypotension unresponsive to usual measures 3