"i started taking atenolol (25 mg) right after thanksgiving for heart palpitations. when i saw the dr he said i had sinus tachycardia, but i also have severe panic disorder. i can tell a big difference. i will have a palpitation every now and then but my resting heart rate is down. i haven&#039;t noticed that my anxiety is down so i still take my .25 xanax when i need it. i also haven&#039;t noticed any side effects other than a little dizziness and a little chest tightness. its kind of been a life saver because my palpitations would put me in a panic attack. i would recommend this to anyone that would benefit from it."