Oral misoprostol is rapidly absorbed in postpartum women at term.

OBJECTIVE

To determine the rate of bioavailability of oral misoprostol in the tablet and a new capsule form in women with term pregnancies in the postpartum period.

METHODS

Twenty-seven women received 400 microg of misoprostol orally after delivery of the fetal vertex in either the standard tablet form or crushed in methylcellulose capsules prepared in our pharmacy. Serum levels of misoprostol free acid, the principal metabolite, were measured at 5-, 15- and 30-min intervals after administration of the medication. The pharmacokinetics of the tablet and capsule groups were then compared.

RESULTS

Twenty patients were included in the analysis. At 5 min, there was a trend towards a statistically significant difference in the concentration of misoprostol acid in the tablet group (89 pg/ml) versus the capsule group (20 pg/ml) (p = 0.007). No significant difference in plasma concentration was noted in the two groups at 15 min (tablet group, 256 pg/ml; capsule group, 245 pg/ml; p = 0.85) or 30 min (tablet group, 381 pg/ml; capsule group, 455 pg/ml; p = 0.45).

CONCLUSION

Oral misoprostol is rapidly absorbed and bioavailable in the postpartum period. Misoprostol may prove useful in postpartum management. The novel packaging of misoprostol in capsule form allows for double-blinded studies with similar pharmacokinetics to the standard tablet.