NEW YORK (Reuters Health) – In patients with stable angina pectoris, the heart-rate lowering drug ivabradine reduces attack frequency and nitrate consumption – and this is true even outside of clinical trial settings, according to results of a prospective cohort study from Germany.

Acting on the sinoatrial node, ivabradine selectively inhibits the I-f current of cardiac pacemaker cells, the study investigators explain in the American Heart Journal for October.

Ivabradine has demonstrated antianginal and anti-ischemic efficacy in patients with angina pectoris in randomized controlled trials. However, Dr. Ralf Köster at the University Heart Center Hamburg and the REDUCTION Study Group wanted to test the drug in everyday practice conditions.

The open-label study involved 4954 patients with chronic, stable angina pectoris, treated by 1503 physicians in private practice in Germany. The inclusion criterion was the need for control of angina symptoms along with intolerance of, or contraindications to, beta-blockers.

Within four months after starting ivabradine, subjects’ mean heart rate had fallen from 82.9 beats/min to 70.4 beats/min (p < 0.0001), the investigators report. Over the same period, the average weekly frequency of angina attacks dropped from 2.4 to 0.4 (p < 0.0001), with mean consumption of short-acting nitrates falling from 3.3 to 1.6 U/week (p <0.0001). Blood pressure also decreased between baseline and four months, to a “moderate” extent, but this finding “is apparently not related to ivabradine therapy because ivabradine has previously been shown to have no effect on blood pressure,” the authors said. Dr. Köster’s team observed “no relevant changes” in ECGs. Seventy-eight suspected adverse drug reactions were reported for 57 patients, including nausea (11 cases), dizziness (9), ophthalmic events (10), and cardiac events (11). According to the article, adverse events were related to treatment in 6 patients (primarily visual symptoms), probably related to ivabradine in 18, possibly related in 22, probably unrelated in 8, and not evaluable in 3. Physicians graded the efficacy of ivabradine as excellent or very good in 97% of patients, and patient tolerance as excellent or very good in 98%. “The high number of relative or absolute contraindications to beta-blockers demonstrates that there is a broad therapeutic space for ivabradine in everyday practice,” the investigators conclude. This study was supported by Servier Deutschland, which markets ivabradine as procoralan. Reference:
Am Heart J 2009;158:e51-e57.