Table 1.
Fentanyl pharmacokinetics in adolescents with clinically severe obesity compared to children [8, 10] and obese adults [6].
| Parameter | Severely obese adolescents | Johnson et al. [10] 10–14 yr |
Katz et al. [8] > 6 yr |
Shibutani et al. [6] obese adults |
Shibutani et al. [6] lean adults |
|---|---|---|---|---|---|
| Clinical setting | bariatric surgery | surgery | mechanical ventilation due to critical illness | postoperative analgesia after major elective surgery | |
| ASA category | II or III | I or II | n.a. | III (median) | III (median) |
| n | 6 | 3 | 5 | 10 | 16 |
| Age (yr) | 16.6 ± 1.5 | 12 ± 1.7 * | 9.5 ± 2.8 ** | 47 ± 16 *** (n=39) | 60 ± 16 *** (n=70) |
| TBW (kg) | 137.4 ± 14.3 | 58.3 ± 13.3 *** | 117.3 ± 33.4 n.s. |
68.5 ± 9.5 *** | |
| Dose (μg) | 138 ± 49 | 253 ± 71 a) | |||
| Dose (μg/kg TBW) | 1.0 ± 0.4 | 4.34 ± 1.22 * | 5 (bolus), 0.47– 6.2/h (range) | 1–2 (bolus), 0.5–4.2/h (range) | |
| Mode of administration | bolus dose | bolus dose (2–10 minute infusion) | bolus dose, followed by continuous infusion (steady state) | bolus, followed by continuous infusion (steady state) | |
| Sampling time (h) | up to 24 h | up to 10 h | up to 48 hours post infusion | 24.4 h | 24.6 h |
| CL (mL/min* kg TBW) | 11.2 ± 2.6 | 7.1 ± 1.2 * | 8.0 ± 3.9 n.s. | 8.76 ± 1.74 n.s. | 10.48 ± 1.81 n.s. |
| CL (mL/min) | 1522 ± 310 | 414 ± 70 a) | 986 ± 155 ** | 718 ± 163 *** | |
| Vd (L/kg TBW) | 4.7 ± 2.1 | 1.9 ± 1.0 * | |||
| Vd (L) | 635 ± 282 | 111 ± 61 a) | |||
| t1/2 (h) | 4.8 ± 2.0 | 3.5 ± 1.2 n.s. | |||
p compared with the present study using an unpaired t test with Welch’s correction:
*
p<0.05,
**
p<0.01,
***
p<0.001,
a)
calculated based on mean TBW, not included into statistical analysis.
Abbreviations: TBW = total body weight, CL = total body clearance, t1/2 = terminal elimination half-life, Vd = volume of distribution, n.a. = not applicable, n.s. = not significant.