What is the recommended dosage and usage of Atenolol (beta-blocker) for patients with hypertension or myocardial infarction?

Atenolol Dosage and Usage for Hypertension and Myocardial Infarction

For patients with hypertension, atenolol should be initiated at 50 mg once daily, with titration to 100 mg once daily if needed, while for myocardial infarction, treatment involves initial IV administration followed by oral dosing of 50-100 mg daily. 1

Dosing for Hypertension

• The initial dose of atenolol for hypertension is 50 mg given as one tablet once daily, either alone or added to diuretic therapy 1
• The full effect of this dose will usually be seen within one to two weeks 1
• If optimal response is not achieved, the dosage should be increased to 100 mg once daily 1
• Increasing the dosage beyond 100 mg daily is unlikely to produce any further benefit 1
• The magnitude of blood pressure reduction is related to the initial systolic blood pressure, with higher starting blood pressures showing greater absolute reductions 2

Dosing for Myocardial Infarction

• For patients with definite or suspected acute myocardial infarction, treatment should begin with intravenous administration of 5 mg atenolol over 5 minutes followed by another 5 mg intravenous injection 10 minutes later 1
• IV atenolol should be administered under carefully controlled conditions including monitoring of blood pressure, heart rate, and electrocardiogram 1
• In patients who tolerate the full intravenous dose (10 mg), atenolol tablets 50 mg should be initiated 10 minutes after the last intravenous dose followed by another 50 mg oral dose 12 hours later 1
• Thereafter, atenolol can be given orally either 100 mg once daily or 50 mg twice a day for a further 6-9 days or until discharge from the hospital 1
• Early intravenous beta blockade should be avoided in patients with signs of heart failure, evidence of a low output state, increased risk for cardiogenic shock, or other contraindications 3

Contraindications and Precautions

• Atenolol should not be administered to patients with marked first-degree AV block (PR interval >0.24 s), any form of second or third-degree AV block without a functioning pacemaker, history of asthma, or severe LV dysfunction 3
• Patients with evidence of a low-output state, significant sinus bradycardia (heart rate <50 bpm), or hypotension (systolic BP <90 mm Hg) should not receive atenolol until these conditions have resolved 3
• Risk factors for cardiogenic shock include older age, female sex, higher Killip class, lower blood pressure, higher heart rate, ECG abnormality, and previous hypertension 3
• Patients with significant chronic obstructive pulmonary disease who may have reactive airway disease should be given beta blockers very cautiously; initially, low doses should be used 3, 4

Special Populations

• Atenolol is excreted by the kidneys; consequently, dosage should be adjusted in cases of severe impairment of renal function 1
• For elderly patients or those with renal impairment, dose selection should be cautious, usually starting at the lower end of the dosing range 1
• For patients with creatinine clearance between 15-35 mL/min/1.73m², the maximum dosage is 50 mg daily 1
• For patients with creatinine clearance <15 mL/min/1.73m², the maximum dosage is 25 mg daily 1
• Patients on hemodialysis should be given 25 mg or 50 mg after each dialysis under hospital supervision as marked falls in blood pressure can occur 1

Monitoring and Follow-up

• Blood pressure and heart rate should be monitored regularly during treatment 3
• If bradycardia or hypotension requiring treatment or any other untoward effects occur, atenolol should be discontinued 1
• If withdrawal of atenolol therapy is planned in patients with angina pectoris, it should be achieved gradually, and patients should be carefully observed and advised to limit physical activity 1

Comparative Considerations

• In patients with hypertension, the relative cardiovascular benefit of atenolol has been questioned compared to other beta blockers 3, 4
• For post-MI use, the GUSTO-I experience suggests that while atenolol appears to improve outcomes after thrombolysis for myocardial infarction, early intravenous atenolol may be of limited value 5
• The best approach for most post-MI patients may be to begin oral atenolol once the patient is stable 5