Atenolol Increase Cause Weight Gain

43 y/o, 6'0, 260 lbs. Very active- workout daily, 30-40 mins cardio/day.  Take Atenolol for Irregular Heart Rhythm and Anxiety Disorder.  Started out taking 25 mgs in 2001 and in Dec 2008 it was increased to 50 mgs due to a couple of mild episodes.  Since the increase in dosage, I have put on 15-20 lbs despite increasing my cardio workout.  Since I have a family history of Type II Diabetes, I am concerned with the extra weight and inability to take it off.  Should I speak to my physician about cutting back the dosage to 25 mg?  Can an increase in Atenolol cause weight gain of 20 lbs in a year?

[Alison L, RPh]

Weight gain can occur as a side effect of some beta blockers, especially the older ones, such as atenolol. The average weight gain is between 2 and 4 pounds. It is important to note that weight gain may also be due to fluid retention, which may indicate worsening heart failure.  If you have sudden weight gain — a weight gain of 3 to 4 pounds in 24 to 48 hours — consult your doctor promptly.