METOPROLOL (Lopressor)


Name: METOPROLOL (LopressorR)
Classification: beta 1 and beta 2 selective receptor blocker
  • decreases heart rate
  • prolongs diastolic time; increases time for coronary perfusion and cardiac filling
  • decreases AV conduction; useful in treating rapid supraventricular arrhythmias
  • decreases myocardial contractility
  • decreases myocardial 02 consumption in angina (decreased rate and contractility); strongly recommended to prevent or manage heart failure post MI
  • decreases blood pressure
  • can cause bronchoconstriction
  • Acute Myocardial Infarction: 
    • 5 mg IV direct q2min x 3 doses
  • Atrial Fibrillation: 
    • 2.5-5mg IV direct q2-5min as IV push to a maximum of 15 mg over 15 minutes
  • Intermittent bolus:
    • 5-15mg IV direct q4-8h
Adverse Effects:
  • bradycardia
  • AV blocks
  • hypotension
  • decreased cardiac output
  • bronchospasm
  • acute pulmonary edema
  • electrolyte imbalances
  • may mask tremors and tachycardia associated with insulin induced hypoglycemia
  • may increase systemic vascular resistance
  • IV direct at a rate of 2.5 mg/min
  • should be used with caution in patients with asthma, COPD, peripheral vascular disease as beta blockade may cause bronchoconstriction, bradyarrhythmias or AV block
  • Reduce dose in hepatic dysfunction
Drug Interactions:
  • metoprolol + beta sympathomimetics = antagonizes bronchodilation
  • metoprolol + lidocaine = increased lidocaine toxicity
  • metoprolol + procainamide = increased procainamide levels
  • metoprolol + verapamil = hypotension, AV block
Monitoring Therapy:
  • continuous heart rate and rhythm
  • PR interval
  • blood pressure
  • urine output
  • blood glucose
  • liver function
Adult Critical Care Protocol:
  • May be administed IV direct or by IV infusion by a nurse in Adult Critical Care
  • Continuous infusions must be administered by infusion device with pump library enabled.

Lynne Kelly, Pharmacist, CCTC
Brenda Morgan, Clinical Nurse Specialist, CCTC
Last Update: September 20, 2018