When should metoprolol (beta-blocker) be held and what are the considerations for discontinuation?

When to Hold Metoprolol: Guidelines and Considerations

Metoprolol should be held when a patient presents with symptomatic hypotension (systolic BP <90 mmHg), significant bradycardia (heart rate <50 bpm), decompensated heart failure, or high-degree heart block. These conditions represent situations where continued beta-blockade could worsen the patient's clinical status and increase morbidity and mortality.

Specific Conditions Requiring Metoprolol to be Held

Hemodynamic Parameters

• Heart rate <50 bpm with worsening symptoms - Hold metoprolol and consider halving the dose when restarting 1
• Symptomatic hypotension - Hold if dizziness, light-headedness, or confusion occurs with low blood pressure 1
• Systolic blood pressure <90 mmHg - Temporary discontinuation recommended 1

Cardiac Conditions

• Decompensated heart failure with signs of low cardiac output (oliguria, worsening symptoms) 1
• Cardiogenic shock - Absolute contraindication 1
• Second or third-degree AV block without a functioning pacemaker 1
• Sick sinus syndrome without permanent pacemaker 1, 2

Pulmonary Conditions

• Severe bronchospasm - Consider temporary discontinuation in acute severe exacerbation 2
• Status asthmaticus - Contraindicated during acute episodes 2

Perioperative Considerations

Beta-blockers should NOT be routinely discontinued before major surgery 2. Abrupt discontinuation can lead to:

• Rebound hypertension
• Worsening angina
• Increased risk of myocardial infarction
• Ventricular arrhythmias

Temporary Dose Reduction vs. Complete Discontinuation

1. For mild-moderate symptoms:

   • Consider halving the dose rather than complete discontinuation 1
   • Monitor patient closely and reassess within 1-2 weeks 1

2. For severe symptoms:

   • Temporary complete discontinuation may be necessary 1
   • Seek specialist advice before discontinuing if possible 1

3. For shocked or severely hypoperfused patients:

   • Temporary discontinuation is advised 1
   • Re-institution should be attempted before discharge 1

Restarting After Discontinuation

If metoprolol must be discontinued for any reason:

• Never stop abruptly unless absolutely necessary due to risk of rebound effects 2
• When restarting, begin at a lower dose (12.5-25 mg) 1, 3
• Gradually titrate up at 2-4 week intervals 1
• For patients with coronary artery disease, taper over 1-2 weeks when discontinuing 2

Special Considerations

• Heart failure patients: Even during decompensation, complete discontinuation is rarely necessary; dose reduction is often sufficient 1
• Post-MI patients: Continuation of beta-blockers is particularly important; adjust dose rather than discontinue 1
• Elderly patients: May be more sensitive to hypotensive effects; consider lower threshold for dose reduction 3

Monitoring When Restarting

When restarting metoprolol after holding:

• Check heart rate and blood pressure before each dose titration
• Monitor for signs of worsening heart failure (weight gain, dyspnea, edema)
• Consider ECG to exclude heart block if bradycardia develops 1
• Review other medications that may slow heart rate (digoxin, amiodarone, calcium channel blockers) 1

Remember that abrupt discontinuation of metoprolol can lead to significant adverse outcomes including rebound hypertension, worsening angina, and increased risk of cardiovascular events. When possible, dose reduction is preferable to complete discontinuation.