What are the maximum doses of common blood pressure (BP) medications, such as beta-blockers (e.g. atenolol), angiotensin-converting enzyme (ACE) inhibitors (e.g. lisinopril), calcium channel blockers (e.g. amlodipine), and diuretics (e.g. hydrochlorothiazide (HCTZ))?

Maximum Doses of Common Blood Pressure Medications

The maximum doses of common blood pressure medications are: atenolol 100mg daily, lisinopril 40mg daily, amlodipine 10mg daily, and hydrochlorothiazide 25mg daily, with dose adjustments needed for elderly or frail patients. 1

Beta-Blockers (e.g., Atenolol)

• Starting dose: 25-50mg daily
• Maximum dose: 100mg daily
• Beta-blockers are not preferred as initial therapy for hypertension but may be considered in younger patients or those with specific indications 2
• When adding a second drug to a beta-blocker, a calcium channel blocker is preferred over a thiazide-like diuretic to reduce diabetes risk 2

ACE Inhibitors (e.g., Lisinopril)

• Starting dose: 10mg daily
• Maximum dose: 40mg daily
• Preferred first-line agent for non-Black patients 2
• Requires monitoring of renal function and potassium levels 1
• Particularly beneficial for patients with diabetes, albuminuria, chronic kidney disease, or coronary artery disease 1

Calcium Channel Blockers (e.g., Amlodipine)

• Starting dose: 5mg daily
• Maximum dose: 10mg daily
• Effective as monotherapy or in combination with other agents 1
• Dihydropyridine calcium antagonists (like amlodipine) have not shown safety concerns in controlled trials 2
• Preferred first-line agent for Black patients of African or Caribbean family origin 2

Diuretics (e.g., Hydrochlorothiazide)

• Starting dose: 12.5mg daily
• Maximum dose: 25mg daily
• Thiazide-like diuretics (chlorthalidone 12.5-25mg daily or indapamide 1.5-2.5mg daily) are preferred over conventional thiazides like hydrochlorothiazide 2
• Low-dose thiazides are the accepted first-line treatment for elderly patients 2
• Consider loop diuretics instead of thiazides if creatinine clearance <30 mL/min 1

Dosing Considerations and Combination Therapy

• Most hypertensive patients will require combinations of antihypertensive therapy to achieve optimal control 2
• Submaximal doses of two drugs often result in larger BP reductions with fewer side effects than maximal doses of a single drug 2
• For elderly patients (>80 years) or frail patients, consider starting with lower doses and titrating more gradually 1
• Fixed-dose combinations may improve adherence, especially for patients requiring multiple medications 1

Rational Drug Combinations

• Diuretic + ACE inhibitor/ARB
• Diuretic + beta-blocker
• Calcium antagonist + ACE inhibitor/ARB
• Calcium antagonist + beta-blocker 2

Step-wise Approach to Resistant Hypertension

1. Optimize doses of initial medications before adding additional agents
2. For resistant hypertension, add spironolactone 25mg daily (with caution if potassium >4.5 mmol/L) 2
3. If spironolactone is not tolerated, consider amiloride, doxazosin, eplerenone, clonidine, or beta-blocker 2

Common Pitfalls

• Underdosing medications is a common reason for inadequate BP control 3
• ACE inhibitors have a flat dose-response curve, meaning low doses have the same potency as high doses but shorter duration of action 3
• Avoid excessive lowering of diastolic blood pressure below 70-75 mmHg in elderly patients with coronary heart disease 1
• Monitor for electrolyte abnormalities, particularly when using diuretics, ACE inhibitors, or ARBs 1

Remember that the optimal three-drug combination for resistant hypertension should include a RAS blocker (ACE inhibitor or ARB), a calcium channel blocker, and a thiazide-like diuretic 1.