I was started on Toprol XL 50 mg 3 weeks ago and am stopping it immediately. I have had 3 trips to the ER with shortness of breath and left sided chest pain. Other symptoms include a 10 pound weight gain, leg/feet swelling, difficulty swallowing, tremendous fatigue, headache, periods of feeling faint/lightheaded, extreme nausea and constipation with abdominal bloating. I have never felt so horrible in my life and will NEVER take this drug again.