How much will Amlodipine (calcium channel blocker) lower blood pressure from baseline?

Blood Pressure Reduction with Amlodipine

Amlodipine lowers blood pressure by approximately 12-13 mmHg systolic and 6-7 mmHg diastolic from baseline in patients with mild to moderate hypertension when measured 24 hours after dosing. 1

Evidence from FDA-Approved Labeling

The most definitive data comes from the FDA drug label, which synthesized 15 double-blind, placebo-controlled trials involving 800 patients on amlodipine:

• Supine position: 13/7 mmHg reduction (systolic/diastolic) 1
• Standing position: 12/6 mmHg reduction (systolic/diastolic) 1
• These reductions were placebo-corrected and measured at 24 hours post-dose, demonstrating sustained efficacy throughout the dosing interval 1

Dose-Response Relationship

The magnitude of blood pressure reduction is dose-dependent within the therapeutic range:

• 2.5 mg dose: Minimum effective dose, produces modest reductions 2
• 5 mg dose: Standard starting dose, achieves approximately 11-13/9-10 mmHg reduction 3, 4
• 10 mg dose: Maximum dose, provides the greatest blood pressure lowering effect 1, 2

After 4 weeks of treatment, medium-dose (2.5-5 mg) and high-dose (5-10 mg) groups showed significant reductions compared to placebo, while low-dose groups (1.25-2.5 mg) showed less consistent effects 2

Baseline Blood Pressure Impact

The magnitude of reduction correlates directly with baseline blood pressure elevation 1:

• Patients with moderate hypertension (diastolic 105-114 mmHg) experienced approximately 50% greater response than those with mild hypertension (diastolic 90-104 mmHg) 1
• Normotensive subjects experienced minimal changes (+1/-2 mmHg) 1

Time Course of Effect

The blood pressure lowering effect follows a predictable pattern:

• Single dose: Blood pressure decreases gradually over 4-8 hours, with peak effect at 6-12 hours post-dose 1, 5
• Chronic dosing: Steady-state is reached after 7-8 days of consecutive daily dosing 1
• 24-hour control: Maintenance of effect throughout the dosing interval with little peak-to-trough variation (20-25% fluctuation) 5, 6

Clinical Trial Data Supporting These Estimates

A well-controlled study using continuous intra-arterial monitoring demonstrated:

• Daytime blood pressure: Reduced from 165/103 to 147/89 mmHg (18/14 mmHg reduction) 6
• Nighttime blood pressure: Reduced from 137/79 to 121/69 mmHg (16/10 mmHg reduction) 6
• The normal circadian pattern was preserved 6

A comparative trial with 188 patients showed amlodipine (mean dose 8.8 mg) produced:

• Supine: -12.8/-10.1 mmHg reduction 4
• Standing: -11.5/-9.8 mmHg reduction 4

Special Populations

Black patients: Calcium channel blockers like amlodipine are particularly effective, showing greater blood pressure reduction compared to ACE inhibitors or ARBs in this population 7, 8

Elderly patients: The effect on systolic pressure is greater in older patients, likely due to higher baseline systolic pressures 1

Diabetic patients: Similar efficacy to non-diabetic patients, with equivalent blood pressure reductions 7

Important Clinical Considerations

• Heart rate remains unchanged with amlodipine therapy (mean change +0.3 bpm in angina patients, no significant change in hypertensive patients) 1, 6
• The gradual onset of action prevents reflex tachycardia 5
• Discontinuation results in slow return to baseline over 7-10 days without rebound hypertension 5
• Most patients require 2 or more antihypertensive medications to achieve target blood pressure <130/80 mmHg 7, 8