The half life of Metoprolol is between 3 and 7 hours. This is the time it takes for the drug levels in your plasma to reduce by half.
For a drug to be totally eliminated from your system it takes around 5.5 times the half life.
As an estimate then, after taking a dose of Metoprolol it should be out of your system within 16.5 to 38.5 hours.

However other factors to consider include:
1. How much and how often you have taken the drug.
2. Your metabolic rate – a slower metabolism will increase the time a drug remains in your system.
3. Your age and health – older age and poor health will generally increase the time the drug stays in your system.
4. Body mass – generally the bigger you are the longer a drug will remain in your system.

You should see your doctor if your symptoms do not go away.