Can amlodipine (calcium channel blocker) cause bradycardia (abnormally slow heart rate)?

From the Guidelines

Amlodipine is unlikely to cause bradycardia as a common side effect, but it may occur in susceptible individuals, particularly those with pre-existing conduction system disorders or when taking other medications that also slow heart rate. Amlodipine is a calcium channel blocker primarily used to treat high blood pressure and certain types of chest pain. While it typically does not significantly affect heart rate in most patients, some individuals may experience a slowing of their heart rate. The mechanism involves amlodipine's action of blocking calcium channels in the heart, which can affect the electrical conduction system and potentially lead to bradycardia in susceptible individuals 1.

Key Points to Consider

• Amlodipine has the most peripheral arterial dilatory effects but few or no AV or sinus node effects, which reduces the likelihood of bradycardia as a side effect 1.
• Patients taking amlodipine who experience unusual fatigue, dizziness, lightheadedness, or fainting should contact their healthcare provider, as these could be signs of bradycardia.
• This risk is higher when amlodipine is combined with beta-blockers, digoxin, or other medications that affect heart rate.
• Typical dosing of amlodipine ranges from 2.5 to 10 mg once daily, with lower doses often recommended for elderly patients who may be more sensitive to these effects.

Clinical Implications

• Amlodipine can be used to control ongoing or recurring ischemia-related symptoms in patients who already are receiving adequate doses of nitrates and beta blockers, or in patients who are unable to tolerate adequate doses of 1 or both of these agents 1.
• The use of amlodipine in patients with mild LV dysfunction is reasonably well tolerated, although its use in UA/NSTEMI has not been extensively studied 1.
• It is essential to monitor patients for signs of bradycardia, particularly when amlodipine is used in combination with other medications that affect heart rate.

From the FDA Drug Label

These decreases in blood pressure are not accompanied by a significant change in heart rate or plasma catecholamine levels with chronic dosing Amlodipine does not change sinoatrial nodal function or atrioventricular conduction in intact animals or man. The FDA drug label does not answer the question.

From the Research

Amlodipine and Bradycardia

• Amlodipine is a dihydropyridine calcium channel antagonist that is extensively used for the treatment of arterial hypertension, with a predominant effect on the peripheral vascular territory 2.
• In most cases of severe intoxication, important hypotension and reflex tachycardia are usually observed 2.
• However, there have been reports of bradyarrhythmias, such as low atrial rhythm, prolonged PR interval, atrioventricular block, and left bundle branch block, in cases of severe amlodipine intoxication 2.
• These rhythm disturbances suggest that, during acute intoxication, dihydropyridine loses its selective action on the vascular territory and can depress automatism and conduction of cardiac electrical stimulus 2.
• In addition, a study found that the combination of amlodipine with certain antidepressants, such as fluoxetine, sertraline, and paroxetine, can intensify side effects of amlodipine, including swelling of lower limbs and headaches, but did not specifically mention bradycardia as a side effect 3.
• Another study found that the most common side effect of interactions between antidepressants and medications used in treatment of cardiovascular disorders was bradycardia, but this was due to the combination of metoprolol or propranolol with SSRI or bupropion, not amlodipine 3.

Amlodipine's General Effects

• Amlodipine is well tolerated and does not appear to cause some of the undesirable effects often associated with other cardiovascular agents, such as adverse changes in serum lipid patterns, cardiac conduction disturbances, or postural hypotension 4.
• The most common adverse effects associated with amlodipine therapy are oedema and flushing, which are related to the vasodilatory action of the drug and are generally mild to moderate in severity 4.
• Amlodipine has been shown to be effective as both an antianginal agent in patients with stable angina pectoris and an antihypertensive agent in patients with mild to moderate hypertension 4, 5.