Tenormin 25mg is a prescription medication containing atenolol, a beta-blocker used to treat high blood pressure, angina, and certain heart rhythm disorders. Each pack contains 28 tablets manufactured by AstraZeneca, with each tablet containing 25mg of atenolol. The tablets come in a calendar pack format to help track daily doses. Atenolol belongs to the class of medications known as beta blockers, which work by blocking the action of certain natural chemicals in the body that affect heart rate and blood pressure. This medication requires a prescription and should be taken exactly as prescribed by your healthcare provider. The distinctive packaging features the AstraZeneca logo and clear labeling of the active ingredient and dosage strength.