Submitted by Gib Williams, Pharmacy Director, Bryn Mawr Hospital
There is currently a nationwide shortage of IV metoprolol. At this time, despite our conservation efforts, there are only a few vials left. The estimated product release date is currently mid-September. Please keep in mind that these dates can be pushed back.
Please see table below from ASHP for alternative agents during this shortage.
Alternatives to Intravenous Beta-Adrenergic Blockers in Specific Clinical Situations
| Situation | Alternatives and Dosing | Comments |
| Acute myocardial infarction, early treatment | Esmolol: Load with 500 mcg/kg intravenous over 1 minute, then infuse 50 mcg/kg/min for 4 minutes. If inadequate response after 5 minutes, continue intravenous infusion at 50 mcg/kg/min, or may increase rate by increments of 50 mcg/kg/min at intervals of > 4 minutes, up to a maximum of 300 mcg/kg/min or until systolic blood pressure is less than 90 mm Hg. Start therapy with an oral beta-adrenergic blocker as soon as possible.
Metoprolol: 5 mg rapid intravenous push, then repeat dose every 2 to 5 minutes for a total of 3 doses (15 mg total dose). Within 15 minutes of the last intravenous dose, start metoprolol 25 to 50 mg orally every 6 hours for 48 hours, then increase to 100 mg orally twice daily thereafter. |
Consider conserving intravenous beta-adrenergic blockers for those patients most likely to benefit from their use.
Dilute esmolol to a final concentration of ≤ 10 mg/mL before infusion (ie, 2.5 g/250 mL or 5 g/500 mL). Discontinue intravenous beta-adrenergic blockers for heart rate < 50 beats per minute or systolic blood pressure < 90 mm Hg. Begin oral therapy only in patients who tolerate intravenous beta-adrenergic blockers. |
| Unstable angina or non-ST-segment elevation myocardial infarction in patients at high risk for ischemic events | Esmolol: Load with 500 mcg/kg intravenous over 2 to 3 minutes, then start continuous infusion at 100 mcg/kg/min. Increase infusion rate by 50 mcg/kg/min every 10 to 15 minutes as needed to reach target heart rate, up to a maximum of 300 mcg/kg/min.
Metoprolol: 5 mg intravenous push over 1 to 2 minutes, then repeat dose every 5 minutes for a total of 3 doses (15 mg total dose). Within 15 minutes of the last intravenous dose, start metoprolol 25 to 50 mg orally every 6 hour for 48 hours, then increase to 100 mg orally twice daily thereafter. Propranolol: Give 0.5 to 1 mg intravenous initially. Within 1 to 2 hours of the intravenous loading dose, start propranolol 40 to 80 mg orally every 6 to 8 hours. |
Consider conserving intravenous beta-adrenergic blockers for those patients most likely to benefit from their use.
Dilute esmolol to a final concentration of ≤ 10 mg/mL before infusion (ie, 2.5 g/250 mL or 5 g/500 mL). Target resting heart rate is 50 to 60 beats per minute. Discontinue intravenous beta-adrenergic blockers for heart rate < 50 beats per minute or systolic blood pressure < 90 mm Hg. Begin oral therapy only in patients who tolerate intravenous beta-adrenergic blockers. |
| Situation | Alternatives and Dosing | Comments |
| Hypertensive
emergency |
Enalaprilat: 1.25 to 5 mg slow intravenous push every 6 hours. In patients taking diuretics, give 0.625 mg initially; may increase to 1.25 mg for second dose if needed.
Esmolol: Load with 250 to 500 mcg/kg intravenous over 1 minute, then infuse 50 to 100 mcg/kg/min for 4 minutes. May repeat loading dose or increase infusion rate to a maximum of 300 mcg/kg/min. Hydralazine: 10 to 20 mg intravenous or 10 to 50 mg intramuscular. May repeat every 4 to 6 hours as needed. Labetalol: 20 to 80 mg slow intravenous push, then 40 to 80 mg intravenous every 10 minutes as needed to reduce blood pressure, up to a maximum dose of 300 mg. May also give 0.5 to 2 mg/min by continuous intravenous infusion, up to a maximum dose of 300 mg. Metoprolol: 1.25 to 5 mg intravenous every 6 to 12 hours. |
In stable patients, the goal is to reduce blood pressure 25% within 1 hour, then further reduce to 160/100 to 160/110 mm Hg in the next 2 to 6 hours.
The hypotensive effects of intramuscular hydralazine are delayed compared with intravenous administration. |
| Hypertension, short-term management in patients unable to take oral medications | Enalaprilat: 0.625 to 1.25 mg slow intravenous push every 6 hours.
Hydralazine: 10 to 20 mg intravenous. May repeat every 4 to 6 hours as needed. May increase to 40 mg/dose if needed. Labetalol: 20 mg slow intravenous push, then 40 to 80 mg intravenous every 10 minutes as needed to reduce blood pressure, up to a total dose of 300 mg/day. Metoprolol: 1.25 to 5 mg intravenous every 6 to 12 hours initially. Titrate to response. Some patients may need up to 15 mg every 3 to 6 hours. |
Consider reserving intravenous beta-adrenergic blockers for those patients with UA and NSTEMI most likely to benefit from their use.
Dilute esmolol to a final concentration of ≤ 10 mg/mL before infusion (ie, 2.5 g/250 mL or 5 g/500 mL |
Comparison of Intravenous Beta-Adrenergic Blockers
| Agent | Receptor antagonist activity | Half-life (hours) | Lipid solubility | Administration |
| Esmolol | Beta-1 | 0.15 | Low | Continuous intravenous infusion. |
| Labetalol | Alpha-1, Beta-1, Beta-2 | 5.5 to 8 | Moderate | Slow intravenous injection or continuous intravenous infusion. |
| Metoprolol | Beta-1 | 3 to 7 | Moderate | Rapid intravenous push, or over 1 to 2 minutes |
| Propranolol | Beta-1, Beta-2 | 2 to 5 | High | Slow intravenous push, at a maximum rate of 1 mg/min. |