When should atenolol (beta-blocker) be held?

When to Hold Atenolol

Atenolol should be held when heart rate drops below 50 beats per minute, systolic blood pressure falls below 90 mmHg, or when patients develop signs of cardiogenic shock, heart failure, or symptomatic bradycardia. 1

General Considerations for Holding Atenolol

Atenolol is a cardioselective beta-1 blocker commonly used for hypertension, angina, and post-myocardial infarction management. While it provides significant cardiovascular benefits, there are specific situations when it should be temporarily withheld:

Vital Sign Parameters

• Heart rate < 50 beats per minute 1, 2
• Systolic blood pressure < 90 mmHg 2
• Signs of hypoperfusion (oliguria, altered mental status) 2

Cardiac Conditions

• Acute heart failure or pulmonary edema 3
• Cardiogenic shock 2
• Severe bradycardia with symptoms 1
• Second or third-degree heart block (without functioning pacemaker) 2
• Marked first-degree AV block (PR interval > 0.24 seconds) 2

Special Clinical Scenarios

Perioperative Management

• For patients undergoing high-risk surgery, continue beta-blockers if already taking them 2
• For non-cardiac surgery, do not abruptly discontinue atenolol due to risk of rebound hypertension and tachycardia 2
• If bradycardia or hypotension occurs during perioperative period, reduce dose rather than completely discontinuing 2

Thyrotoxicosis

• Do not abruptly withdraw atenolol in patients with suspected thyrotoxicosis as this may precipitate thyroid storm 3
• Gradually taper dose under close monitoring if discontinuation is necessary 3

Pregnancy

• Atenolol is classified as category D by FDA for pregnancy 3
• Consider holding or switching to alternative agents, especially in first trimester 2
• Avoid atenolol during pregnancy when possible due to risk of fetal growth restriction 2, 3

Important Precautions When Holding Atenolol

Avoid Abrupt Discontinuation

• Abrupt discontinuation can cause rebound hypertension, tachycardia, and exacerbation of angina 3
• In patients with coronary artery disease, abrupt withdrawal may precipitate myocardial infarction or ventricular arrhythmias 3
• If discontinuation is necessary, taper gradually over 1-2 weeks when possible 3

Monitoring After Dose Reduction or Holding

• Monitor vital signs closely (every 4-6 hours) 1
• Watch for symptoms of beta-blocker withdrawal (tachycardia, increased blood pressure, angina) 3
• Consider ECG monitoring if there are concerns about conduction abnormalities 1

Management Algorithm for Bradycardia on Atenolol

1. Asymptomatic bradycardia (HR 50-60 bpm):

   • Continue atenolol with increased monitoring
   • Consider dose reduction if persistent

2. Mild symptomatic bradycardia (HR < 50 bpm) or SBP < 90 mmHg:

   • Hold current dose
   • Reduce subsequent doses by 50%
   • Reassess in 24-48 hours

3. Severe symptomatic bradycardia or hypotension:

   • Hold atenolol completely
   • Monitor until symptoms resolve
   • Consider gradual reintroduction at lower dose when stable

4. Heart failure or cardiogenic shock:

   • Hold atenolol immediately
   • Provide supportive care
   • Consult cardiology before restarting

Resuming Atenolol After Holding

• Resume at a lower dose (typically 50% of previous dose) once heart rate is consistently above 50 bpm and blood pressure is stable 2
• Titrate dose gradually while monitoring for recurrence of bradycardia or hypotension 2
• Consider alternative beta-blockers with shorter half-life (e.g., metoprolol) if recurrent issues with atenolol 2

Remember that atenolol has a long half-life (6-9 hours in normal renal function, up to 36 hours in renal failure), so effects may persist for 24-48 hours after holding the medication 4.