Hi, please don't take medications on your own and without a proper schedule or prescription by your doctor. It can cause dangerous effects. Please consult a healthcare professional and get monitored for your blood pressure control. Regards.
Yes, from your post it reads like you have access to generic beta blockers, both atenolol and metoprolol are short term, last only a few hours. They are not slow release, one per 24 hours type of medication.
Talk with your prescribing doctor. But, I believe most who are taking regular/fast release beta blockers take them every 12 hours, I do.