Atenolol Dosing for Hypertension
Atenolol is dosed once daily for hypertension, with an initial dose of 50 mg and a maximum effective dose of 100 mg daily. 1
FDA-Approved Dosing Regimen
The FDA label for atenolol specifies once-daily dosing for hypertension 1:
- Initial dose: 50 mg once daily (alone or with diuretic therapy) 1
- Titration: Increase to 100 mg once daily if optimal response not achieved within 1-2 weeks 1
- Maximum dose: 100 mg once daily (increasing beyond 100 mg daily is unlikely to produce further benefit) 1
Evidence Supporting Once-Daily Dosing
The pharmacokinetic properties of atenolol support once-daily administration 2, 3:
- Atenolol maintains 24-hour blood pressure control with once-daily dosing, unlike metoprolol which requires twice-daily dosing due to its shorter half-life 2
- Blood pressure reduction at 25 hours post-dose (trough effect) is significantly better with atenolol compared to metoprolol, demonstrating sustained efficacy throughout the dosing interval 2
- Clinical trials confirm therapeutic equivalence between once-daily and twice-daily atenolol administration at the same total daily dose 4
Dose-Response Relationship
Research demonstrates that 100 mg once daily is the optimal dose 3:
- 50 mg daily produces significant blood pressure reduction (p<0.001) but is submaximal 3
- 100 mg daily achieves the lowest blood pressures (22/15 mmHg reduction from baseline) 3
- 200 mg daily offers no additional benefit and increases side effects (particularly tiredness) compared to 100 mg 3
Special Populations Requiring Dose Adjustment
Elderly and renally-impaired patients require lower starting doses 1:
- Creatinine clearance 15-35 mL/min/1.73m²: Maximum 50 mg daily 1
- Creatinine clearance <15 mL/min/1.73m²: Maximum 25 mg daily 1
- Hemodialysis patients: 25-50 mg after each dialysis under hospital supervision 1
- Elderly patients without renal impairment: Consider starting at 25 mg daily and assess trough blood pressure carefully 1
Common Pitfall to Avoid
Do not confuse atenolol with metoprolol dosing schedules. While both are cardioselective beta-blockers used in hypertension, metoprolol tartrate requires twice-daily dosing due to its shorter half-life 5, 2, whereas atenolol's longer half-life permits true once-daily administration 2, 4. The ACC/AHA guidelines list atenolol as 25-100 mg in 2 divided doses 5, but this reflects conservative dosing options rather than necessity—the FDA label and clinical trials clearly support once-daily dosing 1, 3, 4.
Monitoring for Efficacy
Measure blood pressure just prior to the next dose ("trough" blood pressure) to ensure 24-hour control, particularly in elderly or renally-impaired patients on reduced doses 1. This trough measurement is critical because it represents the point of lowest drug concentration and confirms adequate duration of action 1.