I am on atenolol 25mg.dr told me to stop the drug (side effects) but my heart rate went upto 125beats.now he says i go down to atenolol 12.5mg.will this low dose keep my heart rate down and lower side effect (depression) ?

That’s a very low dose. Try it and see if it works.

I would be concerned about a heart rate of 125 which is often not simple benign sinus tachycardia. Have you had an EKG during that rapid rate or an outpatient Holter Monitor to check for atrial fibrillation, supraventricular tachycardias,atrial flutter? Have you been checked for overactive thyroid? Discuss this with your MD.