Intravenous administration of amlodipine (single dose, 10 mg) to 12 volunteers gave a mean plasma half-life of 34 h, mean clearance of 7 ml min-1 kg-1 and a mean apparent volume of distribution of 21 l kg-1. Oral administration (single dose, 10 mg) to the same 12 volunteers gave a mean systemic availability of 64% and a mean plasma half-life of 36 h. In a second study, repeated oral administration (once daily for 14 days, 15 mg) to 28 volunteers resulted in steady state plasma drug concentration being reached after seven doses, an accumulation of approximately threefold and a mean half-life of 45 h.