title: Pharmacokinetic study of low- versus high-dose medroxyprogesterone acetate (MPA) in women.
abstract: The present study was conducted to compare the pharmacokinetics (PK) of low-dose versus high-dose medroxyprogesterone (MPA) as a once-daily oral administration. Of 32 patients, all women, enrolled in this PK study, 18 received 600 mg MPA daily and 14 received 1200 mg daily. Detailed PK data were obtained on day 1 and after more than 4 weeks of MPA treatment. In addition, multiple data for the minimum steady-state concentration (Css min) were analyzed. The MPA serum concentrations were measured by high-performance liquid chromatography. Wide interpatient variability was found in the PK parameters obtained both on day 1 and after more than 4 weeks. There were no clear relationships between the oral dose and the MPA peak concentration (Cmax), area under the time versus concentration curve (AUC), or mean Css min. Weight gains of 10% or more were demonstrated more frequently in the high-dose group (P < 0.01). Liver dysfunction (n = 5) did not influence the PK of MPA. Five patients demonstrated extremely low AUC and Cmax (< 10 ng/ml) values on day 1. Phenobarbital, dexamethasone and betamethasone were being taken concomitantly with the MPA each by one patient. The serum MPA concentrations were markedly increased after the discontinuation of phenobarbital in that patient, suggesting a drug interaction. At present we cannot recommend the high dose of MPA, except in clinical studies, from a PK or a pharmacodynamic points of view.
authors.affiliation: Department of Medicine, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ohtsu
authors.forename: H
authors.initials: H
authors.lastname: Fujii
authors.forename: H
authors.initials: H
authors.lastname: Wakita
authors.forename: T
authors.initials: T
authors.lastname: Igarashi
authors.forename: K
authors.initials: K
authors.lastname: Itoh
authors.forename: S
authors.initials: S
authors.lastname: Imoto
authors.forename: M
authors.initials: M
authors.lastname: Kohagura
authors.forename: Y
authors.initials: Y
authors.lastname: Sasaki
mesh_terms: D000328:Adult; D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D019540:Area Under Curve; D001943:Breast Neoplasms / Q000188:drug therapy*; D002851:Chromatography, High Pressure Liquid; D002986:Clinical Trials as Topic; D004334:Drug Administration Schedule; D004347:Drug Interactions; D005260:Female; D006801:Humans; D016014:Linear Models; D008111:Liver Function Tests; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D008875:Middle Aged; D018709:Statistics, Nonparametric
chemical_list: D018931:Antineoplastic Agents, Hormonal; D017258:Medroxyprogesterone Acetate