is a drug which reduces the heart rate
so it should be used with extreme caution with slow heart rate. First of all, an ECG should be done to rule out heart blocks. If there is a heart block on ECG diagnosis, or sinus bradycardia
with heart rate of less than 45, Metoprolol should be stopped.
As you mentioned, the heart rate to be in mid 50s, I would suggest to still stop taking this drug and switch over to another drug like Amlodipine
, in combination with Valsartan, which is very safe and effective combination in controlling blood pressure.
To stop Metoprolol, it should be gradually reduced over 1-2 weeks with careful monitoring. However, any change in drug should be done under the guidance of your doctor.
Hope I have answered your query. Let me know if I can assist you further.