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Table 1: Summary of Mean (± SD) Pharmacokinetic Parameters of the (+)-and (-) Enantiomers of Tramadol and M1 and Acetaminophen Following A Single Oral Dose Of One Tramadol/ Acetaminophen Combination Tablet (37.5 mg/ 325 mg) in Volunteers aceta-Parameter a (+)-Tramadol (-)-Tramadol (+)-M1 (-)-M1 minophen Cmax (ng/ mL) 64.3 (9.3) 55.5 (8.1) 10.9 (5.7) 12.8 (4.2) 4.2 (0.8)
tmax (h) 1. 8 (0.6) 1.8 (0.7) 2. 1 (0.7) 2. 2 (0.7) 0.9 (0.7)
CL/ F (mL/ min) 588 (226) 736 (244) ----365 (84)
t1/ 2 (h) 5. 1 (1.4) 4.7 (1.2) 7. 8 (3.0) 6. 2 (1.6) 2.5 (0.6) a For acetaminophen, Cmax was measured as µg/ mL. A single dose pharmacokinetic study of ULTRACET in volunteers showed no drug interactions between tram-adol and acetaminophen. Upon multiple oral dosing to steady state, however, the bioavailability of tramadol and metabolite M1 was lower for the combination tablets compared to tramadol administered alone. The de-crease in AUC was 14% for (+)-tramadol, 10.4% for (-) -tramadol, 11.9% for (+)-M1 and 24.2% for (-)-M1. The cause of this reduced bioavailability is not clear. Following single or multiple dose administration of ULTRACET, no significant change in acetaminophen pharmacokinetics was observed when compared to acetaminophen given alone. Absorption Text Continues Below
The absolute bioavailability of tramadol from ULTRACET tablets has not been determined. Tramadol hydrochlo-ride has a mean absolute bioavailability of approximately 75% following administration of a single 100 mg oral dose of ULTRAM ® tablets. The mean peak plasma con-centration of racemic tramadol and M1 after administration of two ULTRACET tablets occurs at approximately two and three hours, respectively, post-dose. Peak plasma concentrations of acetaminophen occur within one hour and are not affected by co-administra-tion with tramadol. Oral absorption of acetaminophen following administration of ULTRACET occurs primarily in the small intestine. Page: << Prev | 1 | 2 | 3 | 4 | 5 | Next >>
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