Side Effects of Amlodipine-Benazepril Combination
The combination of amlodipine and benazepril is generally well-tolerated with a low rate of serious adverse events, but patients should be monitored for peripheral edema, cough, dizziness, and potential metabolic effects.
Common Side Effects
Most Frequent Adverse Events
Based on the ACCOMPLISH trial involving over 11,000 high-risk hypertensive patients, the risk of serious drug-related adverse events was low and similar between benazepril-amlodipine and benazepril-hydrochlorothiazide groups 1.
From amlodipine component 2:
- Peripheral edema (dose-related: 1.8% at 2.5mg, 3.0% at 5mg, 10.8% at 10mg vs 0.6% placebo)
- Headache (6% vs 4% placebo)
- Dizziness (4% vs 2% placebo)
- Flushing (dose-related: 0.7% to 2.6%)
- Fatigue (4.5% vs 2.8% placebo)
- Palpitations (dose-related: 0.7% to 4.5%)
From benazepril component 3:
- Cough (0.5% discontinuation rate; more common with ACE inhibitors)
- Headache (6% vs 4% placebo)
- Dizziness (4% vs 2% placebo)
- Postural dizziness (2% vs 0% placebo)
- Somnolence (2% vs 0% placebo)
Important Clinical Observation
A key advantage of the combination is that peripheral edema from amlodipine occurs LESS frequently when combined with benazepril compared to amlodipine monotherapy 4, 5. Studies show edema rates of 4.5-5.5% with combination therapy versus 9.2% with amlodipine alone 4. This is clinically significant as edema is often dose-limiting with calcium channel blockers.
Serious but Rare Adverse Events
Cardiovascular
- Arrhythmias (including ventricular tachycardia, atrial fibrillation)
- Bradycardia
- Syncope
- Peripheral ischemia
Hypersensitivity Reactions
- Angioedema (contraindicated if history with ACE inhibitors) 6, 7
- Stevens-Johnson syndrome
- Pemphigus
- Dermatitis, pruritus, rash
Metabolic/Laboratory
- Hyperkalemia (especially with renal disease or potassium supplements) 6, 7
- Hyponatremia
- Elevated liver enzymes
- Elevated serum bilirubin
- Hyperglycemia
Renal
Gender-Specific Considerations
Women experience higher rates of certain side effects 2:
- Edema: 14.6% in women vs 5.6% in men
- Flushing: 4.5% in women vs 1.5% in men
- Palpitations: 3.3% in women vs 1.4% in men
Race-Specific Observations
In comparative studies, Black patients required higher combination doses (amlodipine/benazepril 10/40 mg) to achieve blood pressure reductions similar to White patients 8. However, side effect profiles remained comparable across racial groups.
Discontinuation Rates
Overall discontinuation due to adverse events is low: approximately 5% with benazepril and 1.5% with amlodipine 2, 3. The most common reasons for stopping therapy are:
- Headache (0.6%)
- Cough (0.5%)
Contraindications and Absolute Warnings
Do NOT Use If:
- Pregnancy (both components are contraindicated; women of childbearing age need reliable contraception) 6, 7, 3
- History of angioedema with ACE inhibitors 6, 7
- Concurrent use with ARBs or direct renin inhibitors (increases hyperkalemia and renal dysfunction risk) 1, 9, 10
Use with Extreme Caution:
- Severe left ventricular dysfunction or heart failure with reduced ejection fraction (amlodipine component) 11, 9, 12
- Bilateral renal artery stenosis 6, 7
- Severe renal impairment (GFR <30 mL/min)
- Concurrent potassium-sparing diuretics or potassium supplements
Monitoring Requirements
Essential monitoring parameters:
- Serum potassium and creatinine periodically (especially first few weeks) 6, 7
- Blood pressure for hypotension/orthostatic hypotension (particularly in elderly) 10
- Renal function in patients with pre-existing kidney disease
- Signs of angioedema (facial/tongue swelling, difficulty breathing)
Comparative Safety Profile
Research demonstrates that respiratory adverse events, particularly cough, occur more frequently with amlodipine-benazepril (17 patients) compared to valsartan-hydrochlorothiazide (5 patients) 13. However, the combination showed beneficial metabolic effects including preservation of glomerular filtration rate and improvements in glycemic control.
Clinical Pearls
- The combination is better tolerated than expected based on individual component profiles
- Edema paradoxically decreases when ACE inhibitor is added to calcium channel blocker
- Cough from benazepril is less common than with older ACE inhibitors like captopril 3
- Most side effects are mild to moderate and do not require discontinuation
- No clinically significant metabolic derangements in lipids, glucose, or uric acid with standard dosing 2