Table 3 Pharmacokinetic parameters (geometric mean or median (T_max) and range) for morphine following a single oral administration of codeine (0.3, 0.6 and 1.2 mg/kg) or a single IV administration (0.2 mg/kg) of morphine to adult horses. All values reported were generated using non-compartmental analysis

C(0) ng/mL

–

–

–

191.1 (167.3–235.0)

C_max ng/mL

1.26 (0.855–1.74)^bc

2.11 (1.50–3.03)^ac

3.37 (2.16–4.50)^ab

–

T_max (h)

6.0 (0.5–8.0)

6.0 (0.25–12.0)

7.0 (0.5–24.0)

–

Lambda_z(1/h)

0.048 (0.015–0.089)

0.052 (0.027–0.072)

0.067 (0.046–0.089)

0.138 (0.036–0.215)

HL Lambda_z (h)^*

12.3 (7.76–46.2)

12.6 (9.56–26.0)

10.0 (7.82–15.2)

5.17 (3.22–19.4)

Vdss (L/kg)

–

–

–

6.72 (4.36–11.9)

CL (mL/h/kg)

–

–

–

1967 (1584–2448)

AUC_0-inf (h*ng/mL)

29.7 (15.4–91.4)^c

48.4 (36.1–82.3)^c

74.5 (57.2–111.4)^abd

101.7 (81.7–126.2)^c