Table 1.
Patients' characteristics
| Characteristic | Middle age | Elderly |
|---|---|---|
| Number of patients | 80 | 31 |
| Sex (male/female) | 65/15 | 21/10 |
| Age (year) | 55 ± 11 (53, 58) | 75 ± 4 (73, 76)* |
| Weight (kg) | 68 ± 10 (65, 70) | 60 ± 11 (56, 64)* |
| CYP2D6 genotype | ||
| Hom-EMs | 24 | 10 |
| *1/*1 | 16 | 4 |
| *1/*2 | 8 | 3 |
| *2/*2 | 0 | 3 |
| Het-EMs | 43 | 13 |
| *1/*5 | 2 | 1 |
| *1/*10 | 32 | 9 |
| *1/*21 | 1 | 0 |
| *2/*5 | 0 | 1 |
| *2/*10 | 8 | 2 |
| IMs/PMs | 13 | 8 |
| *5/*10 | 0 | 1 |
| *5/*36 | 0 | 1 |
| *10/*10 | 12 | 4 |
| *10/*21 | 0 | 1 |
| *10/*36 | 0 | 1 |
| *21/*36 | 1 | 0 |
| Flecainide daily dose (mg kg−1) | 2.4 ± 0.8 (2.3, 2.6) | 2.7 ± 0.9 (2.4, 3.0) |
| Serum conc. (ng ml−1) | ||
| Flecainide | 247 ± 108 (223, 271) | 391 ± 207 (318, 464)* |
| MODF | 59 ± 38 (50, 67) | 64 ± 34 (52, 76) |
| MODLF | 28 ± 20 (24, 33) | 28 ± 17 (22, 34) |
| Concentration-to-dose ratio | 105 ± 39 (97, 114) | 142 ± 50 (124, 159)* |
| Metabolic ratio | 2.8 ± 1.5 (2.5, 3.2) | 4.2 ± 2.6 (3.3, 5.1)* |
*
Significant difference between middle age and elderly was observed at P < 0.05. Results are presented as number or mean ± standard deviation (95% CI). Hom-EMs, homozygous extensive metabolizers; Het-EMs, heterozygous extensive metabolizers; IMs/PMs, intermediate and poor metabolizers; MODF, m-O-dealkylated flecainide; MODLF, m-O-dealkylated lactam of flecainide.