Clinical pharmacokinetics of nimodipine in normal and impaired renal function

Twelve patients with different degrees of renal function were investigated. Six of them had moderately impaired renal function (glomerular filtration rate-GFR 20-60 ml/min) and six were preuraemic (GFR less than 20 ml/min). Patients received a single oral dose of 30 mg nimodipine on the first and eighth day, from the second to the seventh day they received 30 mg thrice daily. The results of this study were compared with the data of a similar study with six healthy volunteers (GFR greater than 90 ml/min) who also received for one week nimodipine 40 mg three times daily. In these subjects peak plasma levels of nimodipine ranged between 15.5 and 106.7 micrograms/1 on first treatment day and did not differ significantly from those on the 7th day of therapy ranging between 17.0 and 80 micrograms/1. Mean terminal elimination half-life of nimodipine was 2.77 +/- 0.46 h in normal renal function, but was 22.23 +/- 6.94 h in patients with impaired renal function (12 patients with GFR less than 60 ml/min). The mean area under the plasma level time curve (AUC) with 541.5 +/- 16.93 ng ml-1 h increased in patients with renal insufficiency compared to those with normal renal function (74.65 +/- 9.44 ng ml-1 h). Dosage adjustment of nimodipine appears to be necessary in renal failure.