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100 mg is the limit for atenolol
The dose does not affect kidneys.
Uncontrolled pressure can affect kidneys.
It has some effects on lipids
You can very well change - the only problem is rebound. You have to taper off slowly every 3 or 4 days > 50 mg > 25 > 12.5 ...
There are several classes of drugs apart from beta blockers and diuretics.../ Angiotensin Receptor Blocker
(ARB); Angiotensin Converting Enzyme Inhibitor (ACEI); Direct Renin
Inhibitor; Calcium Channel Blocker
(CCB) - the list is long / there is more than one drug in each class.
See your doctor - he will guide.
Wishing speedy recovery