By comparison with other calcium antagonist drugs, amlodipine has unique pharmacokinetic properties that are probably attributable to its chemical structure and positive ionic charge at physiological pH. Thus, amlodipine undergoes gradual absorption from the gastro-intestinal tract and is widely distributed throughout body tissues. It is cleared only slowly by metabolism in the liver and so has a long elimination half-life, which makes it suitable for single daily dosing. During steady-state administration there are only small peak-to-trough variations in plasma drug levels and in clinical use these pharmacokinetic properties appear to be associated with a smoother pharmacodynamic effect and a reduced incidence of (early) vasodilator side effects.