From the Guidelines
I recommend switching from metoprolol 71.25mg to atenolol 50mg once daily. Atenolol is a hydrophilic (water-soluble) beta blocker that has minimal penetration across the blood-brain barrier, resulting in fewer central nervous system side effects compared to lipophilic agents like metoprolol. The equivalent dose of atenolol for metoprolol 71.25mg would be approximately 50mg daily, as seen in the dosing guidelines provided by the American College of Cardiology/American Heart Association task force on clinical practice guidelines 1. When making this switch, it's best to start the atenolol the day after the last metoprolol dose to maintain continuous beta-blockade. Monitor blood pressure and heart rate during the transition period, as individual responses may vary. Atenolol is primarily eliminated by the kidneys, so dose adjustment may be necessary in patients with significant renal impairment (reduce to 25mg daily if creatinine clearance is below 35 ml/min). Other hydrophilic options include nadolol (starting at 40mg daily) or bisoprolol (starting at 5mg daily), though atenolol is most commonly used when specifically seeking a hydrophilic alternative to metoprolol.
Some key points to consider when switching to atenolol include:
- Atenolol is not recommended as a first-line agent unless the patient has ischemic heart disease (IHD) or heart failure (HF) 1.
- The dosing frequency for atenolol is typically twice daily, but it can be administered once daily in some cases 1.
- Atenolol can be used in patients with bronchospastic airway disease requiring a beta blocker, but caution is advised 1.
- Avoid abrupt cessation of atenolol, as this can lead to rebound hypertension or other adverse effects 1.
Overall, atenolol is a suitable alternative to metoprolol for patients who require a less lipophilic beta blocker, and its dosing and administration should be guided by the patient's individual needs and medical history.
From the FDA Drug Label
DOSAGE & ADMINISTRATION Hypertension The initial dose of atenolol is 50 mg given as one tablet a day either alone or added to diuretic therapy. Atenolol may be used alone or concomitantly with other antihypertensive agents including thiazide-type diuretics, hydralazine, prazosin, and alpha-methyldopa.
To switch a patient from metoprolol to a less lipophilic beta blocker, atenolol can be considered.
- The initial dose of atenolol is 50 mg given as one tablet a day.
- The patient is currently on metoprolol 71.25mg, but there is no direct information on how to convert this dose to atenolol.
- Given the lack of direct conversion information, it is recommended to start with the initial dose of atenolol 50 mg and adjust as needed based on the patient's response 2.
From the Research
Switching to a Less Lipophilic Beta Blocker
To switch a patient from metoprolol 71.25mg to a less lipophilic beta blocker, the following options can be considered:
- Atenolol: Atenolol is a hydrophilic beta blocker that can be used as an alternative to metoprolol 3.
- Labetalol: Labetalol is a dual alpha and beta blocker that has been shown to be effective in lowering blood pressure and has a more favorable side effect profile compared to traditional beta blockers 4, 5.
Dosing Considerations
When switching to a less lipophilic beta blocker, the dose may need to be adjusted. The following dosing considerations can be taken into account:
- Atenolol: The dose of atenolol can be started at 50mg once daily and titrated up to 100mg once daily as needed 6.
- Labetalol: The dose of labetalol can be started at 100mg twice daily and titrated up to 400mg twice daily as needed 5.
Key Points to Consider
- The patient's clinical status and response to the new beta blocker should be closely monitored after switching.
- The dose of the new beta blocker may need to be adjusted based on the patient's blood pressure response and side effect profile.
- It is essential to consider the pharmacokinetic profiles of the different beta blockers when selecting a new medication 6.