From the Guidelines
Nifedipine does not typically cause bradycardia, as it primarily affects vascular smooth muscle, leading to vasodilation and reflex tachycardia rather than a decrease in heart rate. According to the most recent and highest quality study available 1, nifedipine, a dihydropyridine calcium channel blocker, has the most peripheral arterial dilatory effects but few or no AV or sinus node effects, which distinguishes it from other calcium channel blockers like verapamil and diltiazem that can slow heart rate. The study highlights that the beneficial effects of calcium channel blockers in unstable angina/non-ST-elevation myocardial infarction (UA/NSTEMI) are believed to be due to variable combinations of decreased myocardial oxygen demand and improved myocardial flow, but it does not suggest that nifedipine causes bradycardia.
Key Points About Nifedipine
- Nifedipine works by blocking calcium channels in vascular smooth muscle, leading to vasodilation and a drop in blood pressure.
- The body compensates for this drop in blood pressure by increasing heart rate, resulting in reflex tachycardia rather than bradycardia.
- Common side effects of nifedipine include hypotension, dizziness, flushing, nausea, constipation, and edema, as listed in Table 16 of the study 1.
- While verapamil and diltiazem can cause bradycardia due to their effects on the heart's electrical conduction system, nifedipine does not have significant direct effects on the sinoatrial node or atrioventricular conduction.
Clinical Implications
- Nifedipine can be used to control ongoing or recurring ischemia-related symptoms in patients with UA/NSTEMI, especially when used with concomitant beta blockade.
- The choice of calcium channel blocker should be based on the patient's specific clinical condition, with consideration of potential side effects and interactions with other medications.
- As with any medication, monitoring for adverse effects and adjusting the treatment plan as necessary is crucial in clinical practice, based on guidelines such as those outlined in the study 1 and 1.
From the FDA Drug Label
With nifedipine extended-release tablets, these decreases in blood pressure are not accompanied by any significant change in heart rate Although, like other members of its class, nifedipine causes a slight depression of sinoatrial node function and atrioventricular conduction in isolated myocardial preparations, such effects have not been seen in studies in intact animals or in man In formal electrophysiologic studies, predominantly in patients with normal conduction systems, nifedipine administered as the immediate release capsule has had no tendency to prolong atrioventricular conduction or sinus node recovery time, or to slow sinus rate.
Nifedipine does not cause bradycardia as there is no significant change in heart rate with its use, and it does not slow sinus rate in formal electrophysiologic studies 2 2.
From the Research
Nifedipine and Bradycardia
- Nifedipine, a calcium channel blocker, is generally not associated with bradycardia in most patients 3, 4, 5.
- In fact, nifedipine can cause reflex tachycardia due to its vasodilatory effects, which can lead to a decrease in blood pressure 3, 6.
- However, in certain cases, such as in patients with autonomic neuropathy, nifedipine may induce bradycardia due to the lack of compensatory sympathetic drive 7.
- The study by 7 reported a case of nifedipine-induced bradycardia in a patient with autonomic neuropathy, highlighting the potential for this side effect in specific patient populations.
- In contrast, other studies have found that nifedipine is not typically associated with bradycardia, and may even cause tachycardia as a side effect 3, 6.
- The long-term safety and efficacy study of high-dose controlled-release nifedipine found that the most common drug-related treatment-emergent adverse event was tachycardia, rather than bradycardia 6.