Lowest Dose of Metoprolol for Hypertension
The lowest recommended dose of metoprolol for treating hypertension is 25 mg twice daily for metoprolol tartrate or 25-50 mg once daily for metoprolol succinate (extended-release). 1, 2
Formulations and Initial Dosing
- Metoprolol tartrate (immediate release): Start with 25-50 mg twice daily 1
- Metoprolol succinate (extended-release): Start with 25-50 mg once daily 1
- For elderly patients or those with mild hypertension, 50 mg once daily of metoprolol CR/ZOK (controlled-release) has shown effectiveness 3
- In clinical studies, doses as low as 50 mg once daily of metoprolol CR/ZOK have demonstrated significant blood pressure reduction 24 hours post-dosing in both general and elderly hypertensive populations 3
Titration and Maximum Dosing
- Dosage can be increased gradually every 1-2 weeks if blood pressure control is not achieved 4
- Maximum daily dose is 200 mg for metoprolol tartrate and 400 mg for metoprolol succinate 1
- Titration should aim for a target resting heart rate of 50-60 beats per minute unless limiting side effects occur 4
- For patients at high risk of cardiogenic shock or with contraindications, starting at the lowest possible dose is particularly important 4, 2
Special Populations Considerations
- For elderly patients: Consider starting at the lower end of the dosing range due to potentially higher plasma concentrations from decreased metabolism and hepatic blood flow 2
- For patients with hepatic impairment: Lower initial doses are recommended as elimination half-life can be prolonged up to 7.2 hours depending on severity 2
- For patients with renal failure: No significant dose adjustment is typically needed 2
- For patients with bronchospastic disease: If metoprolol must be used, consider the lowest possible dose and administering in smaller doses three times daily instead of larger doses twice daily 2
Contraindications and Precautions
- Absolute contraindications include signs of heart failure, low output state, increased risk for cardiogenic shock, PR interval >0.24 seconds, second or third-degree heart block, and active asthma or reactive airways disease 1, 2
- Risk factors for cardiogenic shock include systolic BP <120 mm Hg, sinus tachycardia >110 bpm or heart rate <60 bpm 1
- Do not abruptly discontinue metoprolol therapy, especially in patients with coronary artery disease 2
Monitoring
- Blood pressure and heart rate should be monitored at each visit 1
- Target blood pressure reduction should be at least 20/10 mmHg, ideally to 140/90 mmHg 4
- Monitor for signs of worsening heart failure or bronchospasm, particularly during initiation 1, 2
Clinical Evidence for Low-Dose Efficacy
- Studies have shown that controlled-release metoprolol at 50 mg once daily provides significant antihypertensive effects lasting 24 hours 3, 5
- In elderly hypertensive patients, 50 mg daily of metoprolol CR/ZOK produced significant reductions in both supine and standing diastolic pressure 24 hours after dosing 3
- Controlled-release formulations maintain more consistent plasma concentrations, allowing for lower effective doses with once-daily administration 6
The evidence strongly supports starting with the lowest effective dose and titrating upward as needed based on blood pressure response, which aligns with the principle of using the minimum effective dose to reduce the risk of adverse effects while achieving therapeutic goals.