Comparison of the bioavailability and pharmacokinetics of oral methylergometrine in men and women.
OBJECTIVE
To assess and compare the pharmacokinetics and bioavailability of methylergometrine (ME) in men and non-pregnant women.


METHODS
A cross-over design was used for an oral dose of 0.125 mg and an intravenous dose of 0.200 mg of ME in 6 men and 6 non-pregnant women (parallel-design in gender).


RESULTS
After intravenous administration, the pharmacokinetic profile of ME was described with a 2-compartment model. The distribution half-life (t1/2 alpha) in men was 0.19 +/- 0.27 h, in women 0.10 +/- 0.04 h, the elimination half-life (t1/2 beta) 1.85 +/- 0.28 h, respectively, 1.94 +/- 0.34 h and the total body clearance (CL) 33.2 +/- 11.8 l.h-1, and, respectively, 22.18 +/- 3.10 l.h-1. For these intrinsic pharmacokinetic parameters differences between men and women were not statistically significant. After oral administration, the pharmacokinetic profile was described with a 1-compartment model. The lag time was subject dependent and was significantly longer in men 0.33 +/- 0.09 h than in women 0.09 +/- 0.07 h. T1/2 beta in men was 2.08 +/- 0.43 h and was longer than in women 1.42 +/- 0.31 h (p = 0.012). In both men and women a large variation of bioavailability was shown ranging between 22% and 138%.


CONCLUSIONS
This study with oral methylergometrine showed a comparable large interindividual variability in bioavailability in both men and women.
de Groot
A N
AN
Department of Obstetrics and Gynaecology, University Hospital Nijmegen, The Netherlands.
Vree
T B
TB
Hekster
Y A
YA
van den Biggelaar-Martea
M
M
van Dongen
P W
PW
van Roosmalen
J
J
D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D001774:Blood Chemical Analysis; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008755:Methylergonovine / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D008875:Middle Aged; D010120:Oxytocics / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D012015:Reference Standards
D010120:Oxytocics; D008755:Methylergonovine