Tenormin 100mg 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 in a calendar pack format, manufactured by AstraZeneca. Each tablet contains 100mg of atenolol as the active ingredient. The medication comes in a distinctive white and blue packaging with the AstraZeneca logo. The calendar pack format helps patients track their daily doses. This is a prescription-only medication that should be taken as directed by a healthcare provider. Store at room temperature away from moisture and heat.