Pharmacokinetic/Pharmacodynamic Analysis of Anti-hyperprolactinemic Effect of Terguride Based on Dopamine D2 Receptor Occupancy.

Accession number;03A0227811
Title;Pharmacokinetic/Pharmacodynamic Analysis of Anti-hyperprolactinemic Effect of Terguride Based on Dopamine D2 Receptor Occupancy.
Author; YAMADA YASUHIKO (Univ. of Tokyo, Univ. Hosp.) IRIZUKI NAOKO (Univ. of Tokyo, Univ. Hosp.) TAKAYANAGI RISA (Univ. of Tokyo, Univ. Hosp.) YAMAMOTO KOJIRO (Gunma Univ., Hospital, JPN) SAWADA YASUFUMI (Kyudai Daigakuin'yakugakukenkyuin Seizaisekkeigaku) IGA TATSUJI (Univ. of Tokyo, Univ. Hosp.)
Journal Title;Journal of the Pharmaceutical Society of Japan
Journal Code:F0508A
ISSN:0031-6903
VOL.123;NO.4;PAGE.255-260(2003)
Figure&Table&Reference;FIG.4, TBL.1, REF.19
Pub. Country;Japan
Language;Japanese
Abstract;Terguride has been widely used for the treatment of hyperprolactinemia via partial agonistic action on dopamine D2 receptors in the pituitary. The present study analyzed retrospectively the dopamine D2 receptor binding occupancy (.PHI.) of terguride. The average .PHI. value was estimated to be 14.1% after oral administration of the average/standard therapeutic dose of terguride. Taking the intrinsic activity (.ALPHA.) into consideration, the value of .ALPHA. .PHI. was 2.33%. These results suggest that the antihyperprolactinemic effect of terguride was elicited despite the low receptor occupancy. Furthermore, we developed a pharmacokinetic/pharmacodynamic model for ascertaining the serum prolactin-lowering effect of terguride, considering both the reversible binding to D2 receptors and the effect on the increase rate in the prolactin level. The developed model fit well with the actual data. Although this model could be improved, it could explain the long duration of the antihyperprolactinemic activity of terguride and might be useful for designing its rational dosage regimen. (author abst.)
FULLTEXT