Atenolol is an unbelievably effective medication that put an end to my scary and uncomfortable bouts of palpitations! Atenolol has worked great for me with absolutely no major side effects whatsoever. The only thing that Atenolol did cause was a bit of drowsiness shortly after taking it for the first few days. The tired, drowsy feeling passed and never returned. I have now been taking the medication for approximately seven years. Before taking Atenolol, the palpatations would keep me up nights and I stayed in a constant state of panic. Atenolol definitely helped to rid me of those disconcerting feelings. During the entire seven year period, I have only had to have one dosage increase. I began with 25mg once daily and now take 25mg once in the morning and again before bed. My cardiologist informed me that if I wanted to stop the medication at any point, the taper is very easy with few if any withdrawal symptoms, but I doubt I will ever choose to give this medication up.