Is metoprolol succinate or metoprolol tartrate better for blood pressure control?

Metoprolol Succinate is Superior to Metoprolol Tartrate for Blood Pressure Control

Metoprolol succinate (extended-release) is superior to metoprolol tartrate for blood pressure control due to its once-daily dosing, more consistent 24-hour blood pressure control, and established efficacy in cardiovascular outcomes. 1

Pharmacokinetic Differences

• Metoprolol succinate is an extended-release formulation designed to deliver the medication at a near-constant rate for approximately 20 hours, providing even plasma concentrations over a 24-hour period without the marked peaks and troughs seen with immediate-release formulations 2
• Metoprolol tartrate requires twice-daily dosing (100-200 mg/day in divided doses) compared to once-daily dosing for metoprolol succinate (50-200 mg once daily), which can improve medication adherence 1
• After ingestion, metoprolol succinate tablets disintegrate into individual pellets with each pellet acting as a diffusion cell releasing the drug at a relatively constant rate over approximately 20 hours 3

Blood Pressure Control Benefits

• Metoprolol succinate provides more consistent beta-1 blockade over 24 hours while maintaining cardioselectivity at doses up to 200 mg daily 2
• In comparative studies, metoprolol succinate demonstrated greater reductions in early morning blood pressure, heart rate, and rate-pressure product (a marker of myocardial oxygen demand) compared to other antihypertensives like amlodipine 4
• The extended-release formulation helps control the morning surge in blood pressure, which is a critical period for cardiovascular events 4

Cardiovascular Outcomes

• Guidelines specifically mention metoprolol succinate (not tartrate) as a preferred agent in patients with heart failure with reduced ejection fraction (HFrEF), which is relevant for hypertensive patients with comorbid heart failure 1
• In heart failure trials, metoprolol succinate has demonstrated mortality benefits, while metoprolol tartrate has shown lesser effectiveness in clinical trials 1
• The COMET trial compared carvedilol to immediate-release metoprolol tartrate and found carvedilol superior for mortality outcomes, but this comparison did not include metoprolol succinate, which was the formulation proven effective in the MERIT-HF trial 1

Dosing Considerations

• A 100-mg metoprolol succinate tablet contains 95 mg of metoprolol succinate and is considered to have equivalent activity to 100 mg metoprolol tartrate 3
• Metoprolol succinate dosing ranges from 50-200 mg once daily, while metoprolol tartrate requires 100-200 mg divided twice daily 1
• The convenience of once-daily dosing with metoprolol succinate may improve patient adherence compared to the twice-daily regimen required for metoprolol tartrate 3, 2

Safety Profile

• Both formulations share similar contraindications and precautions, including avoiding abrupt cessation 1
• Metoprolol succinate's more consistent plasma levels may reduce the risk of adverse effects associated with peak concentrations 2
• Both formulations are generally well-tolerated, with studies showing low rates of adverse events 4, 5

Clinical Application

• For patients with hypertension requiring a beta-blocker, metoprolol succinate is preferred due to its once-daily dosing and more consistent 24-hour blood pressure control 1, 4
• For patients with comorbid conditions like heart failure, metoprolol succinate is specifically recommended by guidelines 1
• Metoprolol succinate has been shown effective across various patient populations, including children and adolescents with hypertension 5

Common Pitfalls and Caveats

• The dose equivalence should be considered when switching between formulations (metoprolol succinate 100 mg once daily ≈ metoprolol tartrate 50 mg twice daily) 1, 3
• Avoid abrupt discontinuation of either formulation as this can lead to rebound hypertension or worsening of angina 1
• Beta-blockers, including both metoprolol formulations, are not recommended as first-line agents for hypertension unless the patient has specific comorbidities such as ischemic heart disease or heart failure 1