Can Hydrochlorothiazide (HCTZ) be discontinued without replacement in a patient with well-controlled blood pressure on 25mg HCTZ and 5mg Amlodipine (Amlodipine Besylate)?

Discontinuing HCTZ in a Patient with Well-Controlled Blood Pressure on Combination Therapy

Discontinuing HCTZ without replacement may lead to recurrence of hypertension in up to 59% of patients, and close monitoring is essential if this approach is taken. 1

Evidence on HCTZ Discontinuation

• Studies show inconsistent effects when discontinuing diuretics in patients with controlled hypertension, with hypertension recurrence rates ranging from 21% to 59% 1
• One trial demonstrated that patients who discontinued diuretics had significantly higher systolic (21 mmHg) and diastolic (7 mmHg) blood pressure over one year of follow-up compared to those who continued treatment 1
• However, another trial found no significant difference in blood pressure between diuretic discontinuation and continuation groups during a 3-month follow-up period 1
• When comparing dose reduction versus complete discontinuation, reducing the dose rather than stopping therapy entirely is significantly more effective for maintaining blood pressure control 2

Considerations for HCTZ Discontinuation

• HCTZ at the 25mg dose has been questioned for its efficacy compared to other antihypertensive agents 3, 4
• Meta-analyses show that HCTZ at 12.5-25mg produces less 24-hour blood pressure reduction (6.5/4.5 mmHg) compared to ACE inhibitors, ARBs, beta-blockers, and calcium channel blockers 4
• Amlodipine has demonstrated similar efficacy to HCTZ in blood pressure reduction in some studies, with 24-hour post-dose reductions of -16/-12 mmHg for amlodipine compared to -16/-11 mmHg for HCTZ 5
• Amlodipine 5mg is an effective antihypertensive agent that could potentially maintain blood pressure control as monotherapy in some patients 5

Monitoring After HCTZ Discontinuation

• If HCTZ is discontinued, blood pressure should be checked within 4 weeks to assess for potential hypertension recurrence 1
• Home blood pressure monitoring is recommended to detect early signs of blood pressure elevation 6
• If blood pressure increases above target after HCTZ discontinuation, consider either restarting HCTZ or adjusting the amlodipine dose 6

Risk Factors for Hypertension Recurrence After Discontinuation

• Longer duration of previous hypertension 1
• Higher baseline blood pressure before treatment initiation 1
• Presence of target organ damage 1
• Older age 6

Algorithm for HCTZ Discontinuation

1. Ensure blood pressure is well-controlled (<130/80 mmHg) on current regimen 6
2. Discontinue HCTZ while maintaining amlodipine 5mg 1
3. Implement home blood pressure monitoring with target <135/85 mmHg 6
4. Schedule follow-up within 4 weeks to assess blood pressure control 1, 6
5. If blood pressure remains controlled, continue with amlodipine monotherapy 6
6. If blood pressure increases above target:
   • Consider restarting HCTZ at the same or lower dose 2
   • OR consider increasing amlodipine dose to 10mg if tolerated 6

Potential Benefits of HCTZ Discontinuation

• Reduced risk of metabolic side effects (hypokalemia, hyperuricemia, glucose intolerance) 1
• Improved medication adherence due to simplified regimen 6
• Decreased medication costs 2

Potential Risks of HCTZ Discontinuation

• Recurrence of hypertension in a significant percentage of patients 1
• Possible increased risk of cardiovascular events if blood pressure becomes uncontrolled 1
• Some evidence suggests increased risk of heart failure episodes after diuretic withdrawal 1