Vioxx

[Rofecoxib]

VIOXX Tablets 12.5 mg and 25 mg are bioequivalent to VIOXX Oral Suspension 12.5 mg/ 5 mL and 25 mg/ 5 mL, respectively.

* Registered trademark of MERCK & CO., Inc., Whitehouse Station, New Jersey, USA
COPYRIGHT MERCK & CO., Inc., 1998, 2002
All rights reserved

Food and Antacid Effects

Text Continues Below

---

Food had no significant effect on either the peak plasma concentration (Cmax) or extent of absorption (AUC) of rofecoxib when VIOXX Tablets were taken with a high fat meal. The time to peak plasma concentration (Tmax), however, was delayed by 1 to 2 hours. The food effect on the suspension formulation has not been studied. VIOXX tablets can be administered without regard to timing of meals. There was a 13% and 8% decrease in AUC when VIOXX was administered with calcium carbonate antacid and magnesium/ aluminum antacid to elderly subjects, respectively. There was an approximate 20% decrease in Cmax of rofecoxib with either antacid.

Distribution

Rofecoxib is approximately 87% bound to human plasma protein over the range of concentrations of 0.05 to 25 mcg/ mL. The apparent volume of distribution at steady state (Vdss) is approximately 91 L following a 12.5-mg dose and 86 L following a 25-mg dose. Rofecoxib has been shown to cross the placenta in rats and rabbits, and the blood-brain barrier in rats. Metabolism
Metabolism of rofecoxib is primarily mediated through reduction by cytosolic enzymes. The principal metabolic products are the cis-dihydro and trans-dihydro derivatives of rofecoxib, which account for nearly 56% of recovered radioactivity in the urine. An additional 8.8% of the dose was recovered as the glucuronide of the hydroxy derivative, a product of oxidative metabolism. The biotransformation of rofecoxib and this metabolite is reversible in humans to a limited extent (< 5%). These metabolites are inactive as COX-1 or COX-2 inhibitors.

Page:  << Prev | 1 | 2 | 3 | 4 | 5 | Next >>