What is the treatment and management for a patient with hypotension currently on metoprolol tartrate (Metoprolol) 12.5 milligrams twice daily (BID), and can they be switched to metoprolol succinate (Metoprolol)?

From the Guidelines

For a patient with low blood pressure on metoprolol tartrate 12.5 mg BID, the best course of action is to switch to metoprolol succinate 25 mg once daily, as it provides the same total daily dose with potentially less blood pressure fluctuation due to its extended-release formulation, as recommended by the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1.

Key Considerations

• The patient's current dose of metoprolol tartrate is 12.5 mg BID, which is lower than the usual dose range of 100-200 mg BID, as stated in the guideline 1.
• Metoprolol succinate has a usual dose range of 50-200 mg once daily, making 25 mg a reasonable starting point for this patient, considering the need to minimize blood pressure fluctuations 1.
• The extended-release formulation of metoprolol succinate maintains more consistent blood levels throughout the day compared to the immediate-release tartrate form, which may help minimize blood pressure drops.
• It is essential to monitor blood pressure closely after any medication change, ideally with home measurements twice daily for at least a week, to assess the effectiveness of the new regimen and make further adjustments as needed.

Management and Treatment

• Ensure the patient is adequately hydrated and not taking other medications that could compound hypotension.
• If blood pressure remains low, consider further reducing to metoprolol succinate 12.5 mg daily (by cutting the 25 mg tablet in half).
• If hypotension persists despite dose reduction, consider consulting with a cardiologist to evaluate the continued need for beta-blocker therapy or potential alternative medications based on the patient's underlying condition, as the guideline recommends avoiding abrupt cessation of beta blockers 1.

From the FDA Drug Label

DOSAGE & ADMINISTRATION ... Start patients who appear not to tolerate the full intravenous on metoprolol tartrate tablets either 25 mg or 50 mg every 6 hours (depending on the degree of intolerance) ... In patients with severe intolerance, discontinue metoprolol tartrate ... Geriatric Patients (>65 years) In general, use a low initial starting dose in elderly patients given their greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

The patient is currently experiencing low blood pressure on metoprolol tartrate 12.5 mg BID.

• Dose adjustment may be necessary to manage the low blood pressure.
• The FDA label does not provide direct guidance on switching to metoprolol succinate.
• If a switch to metoprolol succinate is considered, the dosage and frequency should be determined based on the patient's clinical response and tolerance, with careful monitoring of blood pressure and other vital signs 2.
• Caution should be exercised when adjusting the dose or switching to a different formulation, especially in patients with decreased hepatic, renal, or cardiac function.
• The patient's clinical condition and tolerance should guide the treatment and management decisions.

From the Research

Treatment and Management of Low Blood Pressure with Metoprolol Tartrate

• The patient is currently taking metoprolol tartrate 12.5 mg BID for low blood pressure, and the question is whether the treatment can be switched to metoprolol succinate and what the frequency and dosage should be 3.
• Metoprolol is a cardioselective beta-blocking agent that has been widely used in the treatment of mild to moderate hypertension and angina pectoris 3.
• The optimum treatment of hypertension and angina pectoris with metoprolol is achieved through dose titration within the therapeutic range 3.

Switching to Metoprolol Succinate

• There is no direct evidence in the provided studies that compares metoprolol tartrate with metoprolol succinate in terms of efficacy and safety in patients with low blood pressure.
• However, metoprolol succinate is a slow-release formulation that can be administered once daily, which may be beneficial for patients who have difficulty taking multiple doses per day 3.
• The dosage and frequency of metoprolol succinate would depend on the individual patient's response to the medication and their specific medical condition.

Dosage and Frequency

• A study published in 1982 found that 100 mg of metoprolol twice a day controlled mild to moderate hypertension in the majority of patients 4.
• Another study published in 1976 found that metoprolol was given in a dose of 20 mg, and 8 of the 12 patients also received a 50 mg dose, with peak drug plasma concentrations varying between 5 and 80 ng/ml (mean 33) after the 20 mg dose, and between 14 and 212 ng/ml (mean 111) after the 50 mg dose 5.
• The American Journal of Emergency Medicine study found that metoprolol and diltiazem had similar effectiveness for rate control of atrial fibrillation, but metoprolol had a lower occurrence of hypotension 6.

Side Effects and Interactions

• Metoprolol is generally well tolerated, but common side effects include temporary fatigue, dizziness, and headache 3.
• The medication can also cause hypotension and bradycardia, especially in patients with certain medical conditions or taking certain medications 7, 6.
• Patients with asthma or diabetes may be able to tolerate metoprolol better than non-selective beta-blockers due to its cardioselectivity 3, 4.