What is the best next step for a 73-year-old lady with uncontrolled hypertension (high blood pressure), currently on 10mg of amlodipine (amlodipine), who is allergic to ramipril (ramipril, an angiotensin-converting enzyme inhibitor (ACE inhibitor))?

Management of Uncontrolled Hypertension in an Elderly Patient with Amlodipine and Ramipril Allergy

The best next step for this 73-year-old lady with uncontrolled hypertension (204/76 mmHg) on amlodipine 10mg who is allergic to ramipril is to add a thiazide-like diuretic such as indapamide or chlorthalidone to her current regimen.

Current Situation Assessment

• 73-year-old female patient
• Current BP: 204/76 mmHg (severely elevated systolic with controlled diastolic)
• Current medication: Amlodipine 10mg (maximum dose)
• Allergic to ramipril (ACE inhibitor)
• No symptoms of malignant hypertension

Treatment Algorithm Based on Guidelines

Step 1: Evaluate Current Therapy

The patient is on maximum dose amlodipine (10mg) but remains with severely uncontrolled systolic BP. According to the 2020 International Society of Hypertension guidelines, when monotherapy fails to control BP, adding a second agent from a different class is recommended 1.

Step 2: Select Appropriate Add-on Therapy

Based on the ISH 2020 guideline treatment algorithm:

1. Since the patient is allergic to ramipril (ACE inhibitor), options include:
   • Add a thiazide/thiazide-like diuretic
   • Consider an ARB (alternative to ACE inhibitor)
   • Add spironolactone or other agents if above options fail

Step 3: Specific Recommendation

Add a thiazide-like diuretic (indapamide 1.25-2.5mg daily or chlorthalidone 12.5-25mg daily) to the current amlodipine regimen.

Rationale for Recommendation

1. Guideline Concordance: The ISH 2020 guidelines specifically recommend adding a thiazide/thiazide-like diuretic when a calcium channel blocker (amlodipine) alone is insufficient 1.

2. Efficacy: Thiazide-like diuretics have been shown to be highly effective in reducing cardiovascular complications of hypertension, particularly in elderly patients 1.

3. Synergistic Mechanism: The combination of a calcium channel blocker with a diuretic addresses different pathophysiological mechanisms of hypertension, providing complementary effects.

4. Safety Profile in Elderly: Thiazide-like diuretics at low doses are generally well-tolerated in the elderly population when properly monitored.

5. Avoiding ACE Inhibitor Cross-Reactivity: Given the allergy to ramipril, avoiding all ACE inhibitors is prudent. While an ARB could be considered, there is a small risk of cross-reactivity (though much less than between different ACE inhibitors).

Monitoring and Follow-up

• Recheck BP within 2-4 weeks after initiating the combination therapy
• Monitor electrolytes (particularly potassium, sodium) and renal function within 1-2 weeks of starting the diuretic
• Target BP reduction of at least 20/10 mmHg, ideally to <140/90 mmHg (individualized based on frailty) 1
• Assess for symptoms of orthostatic hypotension, especially given patient's age

Alternative Options If First-Line Fails

If the combination of amlodipine and a thiazide-like diuretic fails to adequately control BP:

1. Add an ARB: Consider adding an angiotensin receptor blocker (ARB) such as losartan or valsartan as a third agent. ARBs have a different mechanism than ACE inhibitors and cross-reactivity is uncommon.

2. Add spironolactone: For resistant hypertension, adding spironolactone 25mg daily can be effective, particularly with the patient's current pattern of isolated systolic hypertension 1.

3. Consider beta-blocker: If other options fail or are contraindicated, a beta-blocker could be considered, though they are generally less preferred in elderly patients without specific indications.

Important Considerations and Pitfalls

• Medication adherence: Ensure the patient is taking amlodipine regularly and correctly
• White coat hypertension: Consider ambulatory or home BP monitoring to confirm the severity of hypertension
• Secondary causes: With this degree of systolic hypertension resistant to maximum dose amlodipine, consider screening for secondary causes (renal artery stenosis, primary aldosteronism, etc.)
• Start low, go slow: When adding medications in elderly patients, start with lower doses and titrate gradually
• Avoid excessive diastolic lowering: The patient's diastolic BP is already well-controlled at 76 mmHg; excessive lowering (<70 mmHg) should be avoided in elderly patients 2