Lack of influence of menstrual cycle and premenstrual syndrome diagnosis on pregnanolone pharmacokinetics.

OBJECTIVE

Pregnanolone is a 3alpha-hydroxylated-5beta-reduced metabolite of the female sex steroid hormone progesterone. The compound is currently being evaluated for anaesthetic purposes. Previous studies have indicated a differential physiological response across the menstrual cycle and a different response in patients with premenstrual syndrome (PMS). This study was undertaken to determine whether hormonal changes during the menstrual cycle influence pregnanolone pharmacokinetics and to compare PMS diagnosis-related differences in pregnanolone pharmacokinetics.

METHODS

Seven patients with premenstrual syndrome and seven female controls were given three increasing doses of pregnanolone in the follicular and luteal phase of the menstrual cycle.

RESULTS

Mean pregnanolone elimination half-life varied between 28.4 min and 31.8 min and clearance between 59.6 ml x min(-1) x kg(-1) and 64.0 ml x min(-1) x kg(-1), depending on diagnostic group and cycle phase. No significant differences in pregnanolone pharmacokinetic properties were found between PMS patients and controls in either phase of the menstrual cycle. Furthermore, no differences in pharmacokinetic variables were detected between cycle phases.

CONCLUSION

Pregnanolone pharmacokinetics do not differ between follicular and luteal phase of the menstrual cycle, nor between PMS patients and control subjects.