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Metoprolol (Lopressor / Toprol-XL)

Beta Blockerprescriptionoral · inferred

Cardioselective beta-1 blocker used for hypertension, angina, heart failure, and post-MI. Bioavailability ~50% due to first-pass metabolism via CYP2D6. Available as tartrate (twice daily) and succinate (once daily extended-release).

Projected serum levels — 50 mg, twice daily

Metoprolol (Lopressor / Toprol-XL)
Metoprolol (Lopressor / Toprol-XL) modeled serum levels, 50 mg twice daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 1 days. 0 6.3 12.5 18.8 25 Day 0 Day 4 Day 7 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 1

Maintenance schedule: 50 mg twice daily (oral).

Modeled steady state after ~1 days: peak ≈ 20.6 mg, trough ≈ 2.9 mg body load. Population-based estimate over 15 days for a 50 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Beta Blocker
Route modeled
Oral
Model confidence
inferred
Half-life
3.5 h
Common dose
50 mg
Suggested maximum
400 mg/day
Reference dose range
25–400 mg (single dose)
Suggested cadence
twice daily
Validated against
100 mg oral — Cmax 0.15 mg/L at 1.5 h

Documented interactions

  • contraindicated
    MDA (3,4-Methylenedioxyamphetamine) + Metoprolol (Lopressor / Toprol-XL) CYP inhibition

    MDA (3,4-Methylenedioxyamphetamine) mechanism_based of CYP2D6 predicted to change Metoprolol (Lopressor / Toprol-XL) AUC by ~5.14x

  • contraindicated
    MDMA (Ecstasy) + Metoprolol (Lopressor / Toprol-XL) CYP inhibition

    MDMA (Ecstasy) mechanism_based of CYP2D6 predicted to change Metoprolol (Lopressor / Toprol-XL) AUC by ~5.14x

  • contraindicated
    Paroxetine (Paxil) + Metoprolol (Lopressor / Toprol-XL) CYP inhibition

    Paroxetine (Paxil) mechanism_based of CYP2D6 predicted to change Metoprolol (Lopressor / Toprol-XL) AUC by ~5.14x

  • danger
    Berberine + Metoprolol (Lopressor / Toprol-XL) CYP inhibition

    Berberine reversible_inhibitor of CYP2D6 predicted to change Metoprolol (Lopressor / Toprol-XL) AUC by ~2.68x

  • danger
    Bupropion (Wellbutrin) + Metoprolol (Lopressor / Toprol-XL) CYP inhibition

    Bupropion (Wellbutrin) reversible_inhibitor of CYP2D6 predicted to change Metoprolol (Lopressor / Toprol-XL) AUC by ~2.68x

  • danger
    CBD (Cannabidiol) + Metoprolol (Lopressor / Toprol-XL) CYP inhibition

    CBD (Cannabidiol) reversible_inhibitor of CYP2D6 predicted to change Metoprolol (Lopressor / Toprol-XL) AUC by ~2.68x

Serum checks 42 modeled interaction pairings for metoprolol (lopressor / toprol-xl) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Effect of metoprolol CR/XL in chronic heart failure: Metoprolol CR/XL Randomised Intervention Trial in Congestive Heart Failure (MERIT-HF) MERIT-HF Study Group · Lancet, 1999 DOI

    Landmark RCT of 3,991 patients with NYHA class II-IV heart failure found metoprolol CR/XL reduced all-cause mortality by 34%, sudden death by 41%, and death from worsening heart failure by 49%.

  2. Effects of controlled-release metoprolol on total mortality, hospitalizations, and well-being in patients with heart failure (MERIT-HF) Hjalmarson A et al. · JAMA, 2000 DOI

    Extended MERIT-HF analysis showing metoprolol CR/XL reduced total hospitalizations by 18% and improved quality of life, with benefits across all heart failure severity subgroups.

  3. Metoprolol in acute myocardial infarction (MIAMI). A randomised placebo-controlled international trial The MIAMI Trial Research Group · European Heart Journal, 1985 DOI

    Large RCT of 5,778 patients demonstrating early IV then oral metoprolol in acute MI reduced 15-day mortality by 13%, with greatest benefit in high-risk subgroups.

3 published studies referenced in the app, each with a plain-language summary.