When is metoprolol tartrate used versus metoprolol succinate?

Metoprolol Tartrate vs Succinate: Clinical Applications

Metoprolol tartrate should be used for acute conditions requiring rapid onset and twice-daily dosing, while metoprolol succinate is preferred for chronic conditions requiring once-daily dosing and sustained beta-blockade. 1

Formulation Differences

Metoprolol Tartrate

• Immediate-release formulation
• Administered twice daily (BID) dosing
• Typical dosage: 25-100 mg BID 1
• Rapid onset but shorter duration of action
• Peak effect: 1-2 hours after administration
• Duration: 6-12 hours

Metoprolol Succinate

• Extended-release/controlled-release formulation
• Once-daily (QD) dosing
• Typical dosage: 50-400 mg QD 1
• Provides consistent 24-hour beta-blockade
• Releases drug gradually over approximately 20 hours 2
• 95 mg of metoprolol succinate is equivalent to 100 mg of metoprolol tartrate 2

Clinical Applications

Metoprolol Tartrate (Immediate-Release) Uses

1. Acute cardiovascular conditions:

   • Acute management of supraventricular tachycardia (SVT) 1
   • Acute rate control in atrial fibrillation 1
   • Available in IV formulation for emergent situations (2.5-5.0 mg IV bolus) 1, 3

2. Short-term management:

   • When rapid titration is needed
   • When twice-daily dosing is preferred for specific clinical scenarios
   • When flexibility in dosing is required

Metoprolol Succinate (Extended-Release) Uses

1. Chronic cardiovascular conditions:

   • Chronic heart failure management 4
   • Long-term hypertension control 1, 2
   • Stable angina pectoris

2. Improved adherence situations:

   • Once-daily dosing improves medication adherence
   • Provides more consistent beta-blockade throughout 24 hours
   • Fewer peak-trough fluctuations in drug levels

Specific Clinical Scenarios

Heart Failure

• Metoprolol succinate is specifically indicated for heart failure based on the MERIT-HF trial 4
• Provides more stable plasma concentrations with less fluctuation
• Target dose: 200 mg once daily 4
• Initiate at low dose (12.5-25 mg once daily) and gradually titrate upward 4

Hypertension

• Either formulation can be used effectively
• Succinate preferred for:
  • Once-daily dosing convenience
  • Better 24-hour blood pressure control
  • Improved adherence
• Tartrate may be preferred when:
  • Cost is a concern (generally less expensive)
  • More frequent dosing adjustments are needed

Acute Rate Control

• Metoprolol tartrate is preferred for acute rate control in atrial fibrillation 1
• IV formulation available for emergent situations (2.5-5.0 mg IV bolus) 1, 3
• Can be transitioned to oral tartrate or succinate based on clinical situation

Conversion Between Formulations

When converting between formulations:

• 100 mg metoprolol tartrate (50 mg BID) ≈ 100 mg metoprolol succinate (once daily) 2
• For IV to oral conversion: 5 mg IV ≈ 50 mg oral (10:1 ratio) 3

Clinical Pearls and Cautions

• Avoid abrupt discontinuation of either formulation to prevent rebound hypertension or tachycardia

• Contraindications for both formulations include:

  • AV block greater than first degree (without pacemaker)
  • Decompensated heart failure
  • Severe bradycardia
  • Cardiogenic shock
  • Severe hypotension 1

• Tartrate to succinate transition: When switching from tartrate to succinate, administer the total daily dose of tartrate as a single daily dose of succinate

• Monitoring: For both formulations, monitor heart rate, blood pressure, and symptoms of heart failure or bronchospasm