Metoprolol
Posted by dkwinter

Brand names: Lopressor, Toprol, Betaloc

 

Peak effect:

  • IV: as little 5 minutes if given as IV push; 20 minutes when infused over 10 minutes
  • PO: 1-2 hours

 

Duration of action: 3-6 hours

 

Contraindications:

  • Hypotension
  • Low output state (decompensated heart failure)
  • Increased risk of cardiogenic shock
  • Significant first-degree heart block (PR >=0.24 s); [Metoprolol commonly produces mild first-degree heart block.]. Use caution in patients on other node-blocking agents (CCBs, cardiac glycosides).
  • Second or third-degree heart block
  • Sick sinus syndrome (except in patients with a pacemaker)

 

Indications:

  • Uncontrolled atrial fibrillation: 2.5 to 5 mg IV every 2 to 5 mintes (max total dose 15 mg over 15 minutes). Avoid in patients with decompensated heart failure.
    • One dose of 5 mg every 15 minutes is reasonable in a stable patient, with reduced risk of overshoot.
    • A single dose of 5 mg IV may reduce heart rate by 40 bpm.
  • Atrial fibrillation (maintenance): 25 to 100 mg PO BID.
  • Myocardial infarction: 5 mg IV for up to 3 doses in early treatment of STEMI. Titrate to heart rate and BP.
  • Angina: metoprolol 50 mg PO BID titrated up to 200 mg BID.
  • Heart failure: 12.5 to 25 mg PO once daily. Max increase up to 200 mg daily. Use 12.5 mg if NYHA class III or IV. Be sure to use only after volume status is optimized.
  • Hypertension: 50 mg PO BID up to 225 mg BID. Increase dose weekly.
  • Thyrotoxicosis: 25 to 50 mg PO every 6 hours.

 

Dose conversion:

  • Oral:IV ratio is approximately 2.5:1 (although range is 2:1 to 5:1)
  • Immediate release total daily dose:extended release daily dose ratio is 1:1