I am a female, 55 years old, and have taken Toprol XL 100mg. for the past 5 years for an irregular heartbeat. The symptoms of the premature beats caused an annoying sensation in my chest that I could not tolerate. My cardiologist prescribed several beta blockers before I finally found that Toprol worked the best for me. I have suffered with leg cramps for years....even before taking the Toprol. A nurse who worked for my internist suggested that I try a calcium supplement called "Calcet". This triple calcium supplement is a life saver. I only have to take half of the recommended dosage to have excellent results.....no more being awakened at night by severe leg cramps! The product is sold "over the counter" and can be purchased in any pharmacy or grocery store. As for the side effects of the Toprol; I am sure that I suffer from some adverse reaction as a result of taking the medicine. In any case, as with all medications, the outcome is a trade-off.....one must determine if the harm outweighs the good that the medicine offers.