A Pharmacokinetics, Pharmacodynamics and Safety Study of Warfarin in Combination With Tamiflu (Oseltamivir)

An Open-label, Randomized 2-period Crossover Study to Investigate the Pharmacodynamics, Pharmacokinetics, Safety and Tolerability of Warfarin in Combination With Oseltamivir in Volunteers Stabilized on Warfarin Therapy

This is an open-label, randomized, 2-period crossover study, to evaluate the pharmacokinetics, pharmacodynamics, safety and tolerability of warfarin in combination with Tamiflu (oseltamivir) in participants stabilized on warfarin. Participants will be randomized to receive either their warfarin followed oseltamivir and warfarin, or by oseltamivir and warfarin followed by warfarin. The treatment periods will be separated by a washout period of at least 4 days. Participants will continue receiving warfarin once daily at a prescribed usual dose throughout the study.

Inclusion Criteria:

• Participants must have been receiving warfarin once daily for at least 4 weeks prior to Screening
• Participants must have regular International Normalized ratio (INR) monitoring during warfarin therapy prior to study entry, and be willing to be trained in the use of CoaguCheck devices
• INR must fall within a target range of 2.0-3.5
• Body mass index (BMI) between 18-32 kg/m^2 inclusive

Exclusion Criteria:

• An INR value between screening and Day -1 lower than 2.0 or greater than 3.5
• A change in prescribed daily warfarin dose between Screening and Day -1
• History of any coagulopathy
• Consumption of health products or supplements containing vitamin K
• Pregnant or lactating women
• Confirmed positive urine and/or blood test for drugs of abuse at Screening or Day -1