What antihypertensive medication should I use to control blood pressure in a teenager with obesity, when lisinopril (Angiotensin-Converting Enzyme Inhibitor) is not effective and is causing hyperkalemia?

Antihypertensive Medication for Obese Teenager with Lisinopril-Induced Hyperkalemia

A calcium channel blocker (CCB) such as amlodipine is the most appropriate next antihypertensive medication for an obese teenager with uncontrolled hypertension and hyperkalemia on lisinopril. 1

Rationale for Calcium Channel Blocker Selection

When an ACE inhibitor like lisinopril is causing hyperkalemia and inadequately controlling blood pressure in an obese adolescent, the medication choice should prioritize:

1. Metabolic neutrality: CCBs are considered weight-neutral and do not adversely affect glucose or lipid metabolism 1
2. Potassium safety: Unlike ACE inhibitors and ARBs, CCBs do not increase serum potassium levels
3. Efficacy in obesity-related hypertension: CCBs effectively lower blood pressure in patients with obesity

Why Not Other Classes?

• ARBs: While effective for obesity-related hypertension, they carry similar hyperkalemia risk as ACE inhibitors 1, 2
• Beta-blockers: Should be avoided as first-line treatment in patients with obesity due to:
  • Adverse metabolic effects on lipids and insulin sensitivity
  • Potential to decrease metabolic rate
  • Negative effects on energy metabolism 1
• Thiazide diuretics: Though effective for lowering blood pressure and counteracting hyperkalemia, they have dose-related side effects including:
  • Potential for dyslipidemia
  • Risk of insulin resistance
  • Particular concern in obese patients who are at higher risk for metabolic syndrome and type 2 diabetes 1

Specific Medication Recommendation

• First choice: Amlodipine starting at 2.5 mg daily, titrating up to 5 mg daily as needed 1
  • FDA-approved for children 6-17 years
  • Once-daily dosing improves adherence
  • Can be compounded into a stable suspension if needed

Monitoring Recommendations

1. Check blood pressure every 2-4 weeks during dose titration
2. Schedule follow-up visit in 4-6 weeks until blood pressure normalizes (below 90th percentile for age, height, and gender) 1
3. Continue monitoring serum potassium to ensure resolution of hyperkalemia
4. Consider ambulatory blood pressure monitoring (ABPM) to assess 24-hour control once stabilized on new medication 1

Additional Considerations

• If blood pressure remains uncontrolled on maximum dose of amlodipine, consider adding a low-dose thiazide diuretic (such as chlorthalidone 12.5 mg) as a third agent 3, 4

  • The addition of a thiazide diuretic to a calcium channel blocker has been shown to be more effective than adding a beta-blocker when additional BP control is needed 4
  • Chlorthalidone has better 24-hour blood pressure control than hydrochlorothiazide 3
  • Monitor potassium levels closely after adding a thiazide diuretic

• Emphasize lifestyle modifications alongside pharmacological treatment:

  • DASH diet
  • Moderate to vigorous physical activity 3-5 days per week (30-60 minutes per session) 1
  • Weight management strategies

Remember that hyperkalemia with ACE inhibitors is particularly concerning and can be life-threatening. The switch to a calcium channel blocker addresses both the inadequate blood pressure control and eliminates the risk of medication-induced hyperkalemia.