Key result
Single-dose amlodipine linked to ~52 ms PR prolongation in a patient with baseline first-degree AV block.
Why the study?
Effects of amlodipine on the cardiac conduction system, especially PR interval prolongation, are rare but clinically important.
Does amlodipine cause PR interval prolongation in susceptible individuals with baseline atrioventricular conduction abnormalities?
Case Report (n=1)
Does amlodipine cause PR interval prolongation in susceptible individuals with baseline atrioventricular conduction abnormalities?
Absolute Event Rate: 282% vs 230%
Amlodipine may induce clinically significant PR interval prolongation in susceptible individuals with baseline atrioventricular conduction abnormalities, highlighting the need for ECG monitoring.
May warrant caution with amlodipine in baseline first-degree AV block; hypothesis-generating and requires prospective confirmation.
Amlodipine is a widely used dihydropyridine calcium channel blocker. Its effects on the cardiac conduction system, especially PR interval prolongation, are rare but clinically important. We report a 25‐year‐old healthy male subject in a clinical trial with baseline first‐degree atrioventricular block (PR interval 230 ms). After single‐dose oral amlodipine, his PR interval prolonged significantly to 282 ms at 24 h in both test and reference formulation periods, with asymptomatic sinus bradycardia. The PR interval gradually recovered after drug withdrawal. This case suggests that amlodipine may induce PR interval prolongation in susceptible individuals, especially those with baseline atrioventricular conduction abnormality. Clinicians should strengthen ECG monitoring during amlodipine administration.
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Fu et al. (2026) conducted a case report in Baseline first-degree atrioventricular block (n=1). Amlodipine vs. Baseline was evaluated on PR interval. Single-dose oral amlodipine prolonged the PR interval from a baseline of 230 ms to 282 ms at 24 hours in a 25-year-old male with baseline first-degree atrioventricular block.
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