Should I change the blood pressure medication for an elderly patient with bronchial asthma and hypertension (HTN) who has been taking amlodipine (Amlo) 5mg for a year, is now compliant, but experiencing episodes of cold extremities and a sensation of passing stools, with a normal electrocardiogram (ECG)?

Should You Change the Blood Pressure Medication?

Yes, you should switch from amlodipine to an alternative antihypertensive agent, as the patient's symptoms of cold extremities and sensation of passing stools are likely vasodilatory side effects of amlodipine that warrant medication change, particularly given the contraindication of beta-blockers in bronchial asthma. 1, 2

Understanding the Clinical Picture

The patient is experiencing classic peripheral vasodilatory effects from amlodipine:

• Cold extremities represent peripheral vasodilation causing redistribution of blood flow, which paradoxically can manifest as cold sensations in the extremities 1, 2
• Sensation of passing stools likely reflects gastrointestinal smooth muscle effects from the calcium channel blocker's systemic vasodilatory action 1
• These symptoms occurring despite a normal ECG and now with medication compliance suggest true drug-related adverse effects rather than disease progression 1

Why Amlodipine May Not Be Optimal Here

While amlodipine is guideline-recommended as first-line therapy for hypertension, its side effect profile is problematic in this case:

• The FDA label explicitly notes that amlodipine causes vasodilation-related adverse effects including peripheral edema (most common) and flushing, with these effects being dose-dependent 1
• Peripheral edema occurs in a significant proportion of patients and represents the most prevalent side effect of amlodipine therapy 1, 2
• The drug's extensive conversion to metabolites (90%) and long half-life (30-50 hours) means side effects can persist 1

Recommended Alternative: ACE Inhibitor or ARB

Switch to an ACE inhibitor (such as perindopril 2mg daily) or ARB (such as losartan 50mg daily) as the preferred alternative 3, 4, 5:

• These agents are equally effective first-line options per major guidelines (AHA/ACC, WHO) and avoid the vasodilatory side effects causing the patient's symptoms 4, 5
• ACE inhibitors and ARBs are particularly appropriate in elderly patients with hypertension 4, 5
• Critical consideration: Beta-blockers are absolutely contraindicated in this patient due to bronchial asthma, eliminating that entire drug class from consideration 3, 4

Implementation Strategy

Immediate action plan:

• Discontinue amlodipine 5mg 6, 2
• Initiate perindopril 2mg daily OR losartan 50mg daily 3, 5
• Reassess blood pressure and symptoms within 2-4 weeks 3, 7
• If blood pressure remains uncontrolled (≥140/90 mmHg), increase the ACE inhibitor or ARB dose before considering combination therapy 3, 5

If monotherapy proves insufficient:

• Add a thiazide-like diuretic (indapamide 2.5mg daily) as second-line agent 3
• This combination (ACE inhibitor/ARB + thiazide) provides excellent blood pressure control without the vasodilatory effects of calcium channel blockers 3
• Could consider re-introducing low-dose amlodipine (2.5mg) as third-line only if absolutely necessary for blood pressure control, though this risks recurrence of symptoms 3, 1

Monitoring Parameters

• Check blood pressure at 2-week intervals initially after medication change 3, 7
• Monitor serum creatinine and potassium at baseline and after 2-4 weeks when using ACE inhibitor or ARB 5
• Assess for resolution of cold extremities and gastrointestinal symptoms 6, 2
• Target blood pressure <140/90 mmHg (or <130/80 mmHg if additional cardiovascular risk factors present) 5, 7

Common Pitfall to Avoid

Do not add a beta-blocker despite it being a common second-line agent in hypertension guidelines, as this patient has bronchial asthma which is an absolute contraindication to beta-blocker therapy 3, 4. This significantly narrows the therapeutic options and makes ACE inhibitors/ARBs the logical first choice after discontinuing amlodipine.