After intravenous metoprolol converted the patient’s tachycardia, what oral β‑blocker and dosing regimen should be prescribed at discharge?

Oral Metoprolol Discharge Prescription After IV Conversion

After successful IV metoprolol conversion of tachycardia, prescribe oral metoprolol tartrate 25–50 mg every 6 hours for 48 hours, then transition to 100 mg twice daily for maintenance therapy. 1

Immediate Post-IV Transition Protocol

• Start oral metoprolol tartrate 15 minutes after the last IV dose at 25–50 mg every 6 hours for the first 48 hours 1, 2, 3
• The initial oral dose depends on tolerance to the full 15 mg IV load: patients who tolerated the complete IV regimen should receive 50 mg every 6 hours, while those with partial intolerance should start at 25 mg every 6 hours 1, 3
• This immediate-release formulation (tartrate) is preferred initially because it allows rapid dose adjustment if hemodynamic instability develops 1

Maintenance Dosing at Discharge

• After the initial 48-hour period, transition to metoprolol tartrate 100 mg twice daily as the standard maintenance dose 1, 2
• The maximum maintenance dose is 200 mg twice daily if needed for rate control or secondary prevention 1, 2
• For patients requiring once-daily dosing for adherence, metoprolol succinate (extended-release) 50–200 mg once daily can be substituted after stabilization 2

Critical Contraindications to Verify Before Discharge

Before writing the discharge prescription, confirm the patient does not have:

• Signs of heart failure or low cardiac output (rales on auscultation, S3 gallop, oliguria) 1, 2, 4
• Severe bradycardia (heart rate <50 bpm) or **marked first-degree AV block** (PR interval >0.24 seconds) 1, 2, 4
• Second- or third-degree AV block without a functioning pacemaker 1, 2, 4
• Hypotension (systolic blood pressure <90–100 mmHg with symptoms) 1, 2
• Active asthma or severe reactive airway disease with bronchospasm 1, 2, 4

Special Clinical Contexts

Post-Myocardial Infarction

• For patients with recent MI, the target maintenance dose is metoprolol succinate 200 mg once daily for secondary prevention, titrated gradually over 2–3 weeks 1, 2
• Beta-blockers provide proven mortality reduction (34% decrease in all-cause mortality) in post-MI patients when titrated to target dose 2

Atrial Fibrillation Rate Control

• For ongoing AF rate control, metoprolol tartrate 25–100 mg twice daily or metoprolol succinate 50–400 mg once daily is reasonable 1, 2
• Target resting heart rate is 50–80 bpm for strict control or <110 bpm for lenient control 2

Multifocal Atrial Tachycardia (MAT)

• Oral metoprolol is reasonable for ongoing management of recurrent symptomatic MAT after successful IV conversion 1
• Studies demonstrate that oral metoprolol maintains sinus rhythm in patients with MAT and serious pulmonary disease without adverse respiratory effects 5, 6

Monitoring Parameters at Discharge

Instruct the patient to monitor for:

• Heart rate and blood pressure at each follow-up visit, targeting resting heart rate 50–60 bpm unless limiting side effects occur 1, 2
• Signs of worsening heart failure (increased dyspnea, edema, weight gain) requiring immediate medical attention 2, 4
• Symptomatic bradycardia (dizziness, lightheadedness, syncope with heart rate <60 bpm) 2
• Bronchospasm in patients with any history of reactive airway disease 1, 2

Common Pitfalls to Avoid

• Never abruptly discontinue metoprolol, as this can cause severe exacerbation of angina, myocardial infarction, ventricular arrhythmias, and a 2.7-fold increased risk of 1-year mortality 2
• Do not prescribe extended-release metoprolol succinate immediately after IV conversion; use immediate-release tartrate first to allow rapid titration 1, 2
• Avoid prescribing metoprolol in patients with decompensated heart failure until clinical stabilization occurs (usually after 4 days) 4
• Do not assume all patients tolerate the same dose; elderly patients and those with hepatic impairment require lower initial doses with cautious titration 3

Alternative Beta-Blocker Options

If metoprolol is not tolerated or contraindicated:

• Carvedilol 6.25 mg twice daily (titrated to maximum 25 mg twice daily) provides combined alpha- and beta-blockade with proven mortality benefit in heart failure 1
• Atenolol 25–100 mg daily is an alternative beta-1 selective agent, though its relative cardiovascular benefit has been questioned in hypertension 1