Can you take nifedipine and amlodipine (calcium channel blockers) together?

Concurrent Use of Nifedipine and Amlodipine

Taking nifedipine and amlodipine together is not recommended as they are both dihydropyridine calcium channel blockers with similar mechanisms of action, which increases the risk of hypotension and peripheral edema without providing additional therapeutic benefit. 1

Pharmacological Considerations

Nifedipine and amlodipine belong to the same class of medications - dihydropyridine calcium channel blockers (CCBs). Both drugs:

• Work by blocking calcium influx into vascular smooth muscle cells and cardiac tissue
• Primarily cause peripheral arterial vasodilation
• Have minimal direct effects on cardiac conduction, AV node, and sinus node function 2
• Are used to treat hypertension and angina

Risks of Concurrent Use

Using two dihydropyridine CCBs simultaneously presents several concerns:

• Additive hypotensive effects: Both medications lower blood pressure through the same mechanism, potentially causing excessive hypotension
• Increased peripheral edema risk: Peripheral edema is a common side effect of dihydropyridine CCBs, with rates of 12.3% reported for this class 3
• Pharmacokinetic interactions: The FDA label for nifedipine specifically mentions potential interactions with other calcium channel blockers 1

Evidence Against Combination

The FDA drug label for nifedipine specifically addresses interactions with other calcium channel blockers:

• When nifedipine is co-administered with diltiazem, the AUC of nifedipine increases by factors of 2.2-3.1
• The label recommends caution when co-administering calcium channel blockers and suggests dose reduction 1

While the label doesn't specifically mention amlodipine, both drugs share similar pharmacological properties and mechanisms, suggesting similar interaction potential.

Alternative Approaches

Instead of combining two dihydropyridine CCBs, clinical guidelines support these approaches:

1. Optimize the dose of a single CCB: Either nifedipine or amlodipine can be titrated to an optimal dose before considering additional agents 2

2. Combine a CCB with a different class of antihypertensive:

   • ACE inhibitor or ARB
   • Beta-blocker (with caution)
   • Diuretic

3. Consider switching between nifedipine and amlodipine if one is not effective or causes side effects:

   • Amlodipine has a longer half-life allowing once-daily dosing 4, 5
   • Nifedipine requires twice-daily dosing for optimal blood pressure control 6

Special Considerations

• Heart failure patients: Non-dihydropyridine CCBs (verapamil, diltiazem) should be avoided in heart failure with reduced ejection fraction 3
• Elderly patients: Amlodipine may be preferred for isolated systolic hypertension due to its longer duration of action and once-daily dosing 3
• Monitoring: If switching between these medications, blood pressure should be checked within 2-4 weeks 3

Conclusion

For optimal management of hypertension or angina, use either nifedipine OR amlodipine at an appropriate dose, but not both concurrently. If blood pressure control is inadequate with a single CCB at maximum tolerated dose, add an agent from a different antihypertensive class rather than a second calcium channel blocker.