Mean plasma concentration–time profiles of apixaban (error bars show one standard deviation) in healthy subjects following a single 10 mg dose of apixaban alone or in the presence of multiple doses of (A) ketoconazole, , apixaban 10 mg (n = 19); , apixaban + ketoconazole 400 mg once daily (n = 18) and (B) diltiazem, , apixaban 10 mg (n = 18); , apixaban 10 mg + diltiazem 360 mg once daily (n = 18)