Moderate
amlodipine × enalapril
Calcium channel blockers (dihydropyridines)×Angiotensin-converting enzyme inhibitors (ACEi)
Mechanism
Synergistic BP reduction via two mechanisms: amlodipine causes vasodilation, enalapril blocks the RAAS. The effect is desired in hypertension (fixed-dose combinations exist). In older patients, symptomatic hypotension – especially orthostatic – can occur.
Management
Start both drugs at low doses in older patients. Perform an orthostatic test at the first visit and at 2 weeks. For dizziness, reduce the dose of one component.
Sources
- Lexicomp: Lexicomp Drug Interactions (2024)— Wolters Kluwer Clinical Drug Information, Inc. Lexi-Interact Online, 2024
- Pharmaceutical Press: Stockley's Drug Interactions, 12th edition (2024)— Preston CL (ed.). Stockley's Drug Interactions. 12th ed. London: Pharmaceutical Press; 2024