Is adding another medication, such as a calcium channel blocker (e.g., amlodipine), to the current regimen necessary to control this patient's blood pressure?

Adding a Second Antihypertensive Medication for Blood Pressure Control in a 72-Year-Old Woman

Yes, adding a calcium channel blocker (amlodipine) to the current regimen is strongly recommended for this 72-year-old patient with uncontrolled hypertension (189/109 mmHg) despite being on losartan.

Current Clinical Situation

• 72-year-old female with elevated BP: 189/109 mmHg (improved to 144/85 mmHg on repeat measurement)
• Current medications: Losartan (angiotensin receptor blocker), metformin, statin, aspirin, omeprazole
• Comorbidities: Hypertension, Type 2 Diabetes (improved HbA1c: 49 mmol/mol), hypercholesterolemia
• Recent labs: Mildly elevated potassium (5.3), low iron (8), low ferritin (28)

Rationale for Adding a Second Agent

Evidence for Combination Therapy

• Most patients with hypertension require multiple medications to achieve adequate blood pressure control 1
• The patient's current blood pressure (189/109 mmHg) indicates uncontrolled hypertension despite ARB therapy
• Combination therapy addresses multiple mechanisms contributing to hypertension 2

Recommended Second Agent: Calcium Channel Blocker

1. Dihydropyridine calcium channel blocker (e.g., amlodipine) is the preferred addition because:

   • Provides complementary mechanism to ARB (losartan)
   • Long-acting with once-daily dosing improving adherence 3
   • Preferred combinations include a RAS blocker (like losartan) with a dihydropyridine calcium channel blocker 4
   • Amlodipine has demonstrated efficacy in combination with ARBs/ACE inhibitors 5

2. Starting dose recommendation:

   • Amlodipine 5 mg once daily (can start with 2.5 mg if concerned about fragility) 3
   • Titrate after 7-14 days based on blood pressure response 3

Alternative Options and Considerations

Thiazide Diuretic Option

• A thiazide diuretic would also be an appropriate addition 6, 4
• However, given the patient's mildly elevated potassium (5.3), a calcium channel blocker may be preferable initially

Mineralocorticoid Receptor Antagonist

• Consider adding spironolactone only if blood pressure remains uncontrolled on three medications including a diuretic 6
• Spironolactone has shown significant benefit in resistant hypertension (25 mmHg systolic reduction) 6
• However, risk of hyperkalemia is increased with the patient's already elevated potassium

Monitoring Recommendations

• Recheck blood pressure in 2-4 weeks after initiating amlodipine
• Monitor serum potassium and renal function, especially if a diuretic is added later 6
• Target blood pressure for this 72-year-old patient should be <150/90 mmHg based on age 4
• Consider home blood pressure monitoring to assess treatment efficacy

Special Considerations

• Consider administering at least one antihypertensive medication at bedtime for better coverage during early morning hours 4
• Fixed-dose combination pills can improve adherence if available 4
• Avoid combining two RAS blockers (e.g., adding an ACE inhibitor to losartan) due to increased risk of hyperkalemia 4

Conclusion

Adding amlodipine 5 mg daily to the current losartan regimen is the most appropriate next step for this patient with uncontrolled hypertension, with careful monitoring of blood pressure response and laboratory parameters.