Single- and multiple-dose pharmacokinetics of a low-dose oral contraceptive in women with chronic renal failure undergoing peritoneal dialysis

OBJECTIVE: Our purpose was to compare the pharmacokinetic parameters of oral administration of a 35 µg ethinyl estradiol, 1 mg norethindrone pill in peritoneal dialysis patients and normal women. STUDY DESIGN: A single-dose study was performed with five patients and four controls, followed by a multiple-dose study with five subjects in each group. Pharmacokinetic parameters were calculated by noncompartmental analysis and statistical analysis performed with Mann-Whitney U testing. RESULTS: There is no difference in the pharmacokinetic parameters for norethindrone in peritoneal dialysis patients compared with normal women. During multiple dosing an increased area under the concentration curve and decreased apparent oral clearance was observed for ethinyl estradiol in peritoneal dialysis patients compared with normal women. CONCLUSION: Peritoneal dialysis patients have decreased apparent oral clearance of ethinyl estradiol, leading to slightly higher serum concentrations compared with women with normal renal function. The clearance of norethindrone is the same in peritoneal dialysis patients and normal women.