Try taking the Atenolol in divided dose,.i.e,, 1/4 at a time. My heart rater and bp went too low when I took a whole tablet. All this should be discussed wtih your doctor.
Sometimes these drugs will cause insomnia. It may be better to take them in the morning rather than before bedtime. Check with your doc and tell him or her of the problem.
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We can't make prescription recommendations here, but as sleeping medications such as Ambien require a doctor prescription, ask the doctor writing the prescription.
I take beta blocker, calcium channel blocker and blood thinner, and I occasionally take a generic ambian. This prescription was made by a doctor familiar with my condition and medication regiment.
My other comment, a resting heart rate of 46 is a low, but if it doesn't cause any problems it may be fine, discuss with your doctor. I have never read of a connection between low heart rate and sleeping problems, but that's worth exploring too I think.