It has been prescribed for me to control Atrial Fibrillation episodes.

Following is patient information sheet on Metropolol from National Institutes of Health. It is very important to read and understand the side effects of this drug:

Patient Information (http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000795/)

Drugs.com (http://www.drugs.com/metoprolol.html) has the same information, but in addition has user reports that are very informative. RxList (http://www.rxlist.com/toprol_xl-drug.htm) also has user reports. In addition, here is information on Metoprolol and kidney function (http://healthquestions.medhelp.org/metoprolol-and-kidney-function).