COMPARISON OF THE BIOAVAILABILITY AND PHARMACOKINETICS OF ORAL METHYLERGOMETRINE IN MEN AND WOMEN

Objective: To assess and compare the pharmacokinetics and bioavailabil ity of methylergometrine (ME) in men and non-pregnant women. Design: A cross-over design was used for an oral dose of 0.125 mg and an intrav enous dose of 0.200 mg of ME in 6 men and 6 non-pregnant women (parall el-design in gender). Results: After intravenous administration, the p harmacokinetic profile of ME was described with a 2-compartment model. The distribution half-life (t(1/2 alpha)) in men was 0.19 +/- 0.27 h, in women 0.10 +/- 0.04 h, the elimination half-life (t(1/2 beta)) 1.8 5 +/- 0.28 h, respectively, 1.94 +/- 0.34 h and the total body clearan ce (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 administ ration, the pharmacokinetic profile was described with a l-compartment model. The lag time was subject dependent and was significantly longe r in men 0.33 +/- 0.09 h than in women 0.09 +/- 0.07 h. T-1/2 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%. Conclusion: This study with o ral methylergometrine showed a comparable large interindividual variab ility in bioavailability in both men and women.