Flecainideの血行動態に及ぼす影響—血中濃度との関連

Hemodynamic effects of flecainide in relation to its serum concentration

　FlecainideはVaughan Williams分類のclass ICに属する新しい抗不整脈剤で，特に心室期外収縮，心室頻拍に対する治療効果が高いことで注目されている。しかし，本剤の血行動態に及ぼす影響に関する研究は比較的少なく，しかもそれらは主に静注法によるもので，経口法による評価はほとんどなされていない。今回，本剤1回経口投与法による血行動態値の変動について，血中濃度との関連もあわせて検討した。

The hemodynamic effects of flecainide, a new class IC antiarrhythmic agent, were studied in 30 subjects (23 with congestive heart failure (CHF) and 7 with no overt heart disease). Flecainide was orally given with a dose of 50 mg (group I a), 100 mg (group I b), 200 mg (group I c) for CHF group, and 200mg (group II) for healthy group. The hemodynamic data and serum concentration were measured before and 1, 2, 3, 6 hours after flecainide administration. Pulmonary capillary wedge pressure (PCWP) did not change in group I a and group I b, but was significantly increased in group I c and group II. Cardiac index (CI) was decreased in all groups. Mean pulmonary artery pressure was significantly increased in group I c and group II. Right atrial pressure and mean arterial pressure did not change in all groups. Heart rate was significantly decreased in group I , but no change in group II. Maximal serum concentration was obtained 6 hours after ad-ministration in group I a (104 ng/ml), 3 hours in group I b (203 ng/ml), and 2 hours in group I c (538 ng/ml) and group II (423 ng/ml). Response of PCWP and CI obtained at maximal serum concentration was abnormal in 2 cases (29%) of group I a, 2 cases (25 %) of group I b, 5 cases (83%) of group I c, but none of group II. Increased PCWP and decreased CI were related to serum concentration. Thus, fle-cainide proved to have negative inotropic effects in relation to serum concentration in patients with CHF, but not in subjects with normal cardiac func-tion.