Table 2.
Total and unbound dextromethorphan (DM) and dextrorphan (DX) concentrations in plasma and breast milk at 2 h following a 30 mg oral dextromethorphan dose in lactating women (n=20).
| Total Mean ± SD (95% CI) |
Unbound Mean ± SD (95% CI) |
%Bound Mean ± SD (95% CI) |
|
|---|---|---|---|
|
DM plasma
(ng/mL) |
3.0 ± 2.8 (1.7, 4.3) |
*1.7 ± 1.8 (0.9, 2.6) |
*40 ± 17 (32, 48) |
|
DM breast milk
(ng/mL) |
2.7 ± 2.5 (1.5, 3.9) |
1.6 ± 1.4 (0.9, 2.2) |
40 ± 11 (35, 46) |
| DM breast milk/plasma ratio | 1.0 ± 0.3 (0.8, 1.1) |
*1.1 ± 0.7 (0.7, 1.4) |
not applicable |
|
DX plasma
(ng/mL) |
8.6 ± 3.1 (7.2, 10.1) |
*6.0 ± 2.5 (4.8, 7.2) |
*32 ± 11 (27, 38) |
|
DX breast milk
(ng/mL) |
14.0 ± 8.3 (10.1, 17.9) |
11.7 ± 5.6 (9.0, 14.3) |
14 ± 9 (10, 18) |
| DX breast milk/plasma ratio | 1.6 ± 0.5 (1.4, 1.8) |
*2.0 ± 0.5 (1.8, 2.3) |
not applicable |
Data reported are the arithmetic mean ± standard deviation (SD) and the 95% confidence interval (95% CI) of data from all subjects. The unbound DM and DX concentrations were measured following ultracentrifugation at 37° C for 90 min. and both DM and DX were shown to be stable at 37° C within the timeframe (data not shown).
*
n=19