Before reducing, you should consult your doctor. He or she should have advice on weaning to 12.5 mg if an issue exists. Consulting Google for a Toprol XL 25 mg pill, it shows it as white, oval tablet scored in the middle, so breaking it in half with your doctor's awareness should be easily done. Why are you taking it, I'm taking it because I'm in afib and otherwise develop fast rhythms.

I'm currently on 400 mg Metoprolol Succinate (Long Acting) taken as 200 mg twice per day. I may be put on Sotalol in the hospital and monitored for 2+ days. My point in relating this to you is that although Sotalol is a special kind of combination beta blocker and anti-arrhythmic, I'll be stopped from my 400 mg Metoprolol overnight, no taper.