Plasmaproteinbindingen er 95% uafhængigt af koncentrationen og ændres ikke med alder eller hos patienter med nedsat nyrefunktion, men den frie fraktion fordobles hos patienter med nedsat leverfunktion.
Steady state volume of distribution is about 35 l and plasma protein binding is 95% irrespective of the concentration and is not modified with age and in patients with renal impairment but the free fraction is doubled in patients with hepatic impairment.