What is the doseage that was prescribed to you? Is it once or twice a day?
If once a day, I'd take at night, before bed time (I think no food is necessary, just a full glass of water). Then the tiredness that Metoprolol can cause can be put to good use helping you sleep.
On the other hand, if you are taking it for a high HR, and that becomes most serious during the day when you are up and about, taking the pill with breakfast may be best.
Obviously, if you take twice a day, just do both.
As Jerry mentioned earlier...it would be dependant on the reason for the medication. If it is to reduce your heart rate, it would be best to take it in the morning with your breakfast. If it is for any other reason, than due to the fatigue this drug can cause, you may choose to take it at bedtime.
Hope you are doing well:)
I am on this drug to control my heart rate. I do take it at bedtime because of the fatigue.