Misoprostol oral vs Vaginal
From: Geffrey H. Klein, MD (gklein@bcm.tmc.edu)
Mon Jun 30 21:34:05 1997
The other article in the Green:
I thought it would be interesting for the list because there has been so
much talk about misoprostol:
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Absorption Kinetics of Misoprostol With Oral or Vaginal Administration
MIRIAM ZIEMAN, MD, SUSAN K. FONG, MSc, NEAL L. BENOWITZ, MD, DEBORAH
BANSKTER, MD, AND PHILIP D. DARNEY, MD, MSc
Objective: To compare the pharmacokinetics of vaginal and oral
administration of the prostaglandin E1 analogue, misoprostol.
Methods: Twenty women received 400 microgram doses of misoprostol either
orally or as tablets placed in the vagina. Serum levels of the principal
metabolite, misoprostol acid, were measured at 7.5, 15, 30, 45, 60, 90,
120, and 240 minutes. The first ten women were pregnant and undergoing
first trimester abortions, and the last ten were not pregnant and had
additional blood sampling at 360 minutes. We compared the pharmacokinetics
of misoprostol acid after oral and vaginal administration.
Results: All 20 subjects completed the study. The maximum mean (+/-
standard deviation [SD]) of misoprostol acid differed significantly between
the oral and vaginal groups (277 +/- 124 compared with 165 +/- 86 pg/mL,
respectively, P = .03, analysis of variance), as did the mean +/- SD time
to peak levels (34 +/- 17 compared with 80 +/- 27 minutes, respectively; P
< .001) and areas under the misoprostol concentration versus time come
(mean +/- SD) up to 4 hours (n = 20, 273.3 +/- 110.0 compared with 503.3
+/- 296.7 pg - hour/mL, respec. lively, P = .033) and up to 6 hours (n 10, 300.0 @ 103.3 compared with 956.7 @ 541.7 pg.hour/mL, respectively; P .029). The extent of absorption was highly variable among subjects in each
group.
Conclusion: There are significant differences in the pharmacokinetics of
misoprostol administered by vaginal and oral routes that may explain the
difference observed in clinical efficacy. Assuming that the pharmacologic
effect of misoprostol is related to its concentration in the plasma, our
observation of the prolonged serum concentrations in the vaginal group
suggests that vaginal administration could be dosed at longer intervals
than oral. (Obstet Gynecol 1997;90: 88-92.)
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So I guess it looks like we will ultimately be using it vaginally?
Geffrey H. Klein, MD
listowner: OB-GYN-L
Advisory Board Chairman, OBGYN.net < http://www.obgyn.net >
Co-moderator: sci.med.obgyn
gklein@bcm.tmc.edu gklein@icsi.net
http://members.aol.com/gklein01/geff.html
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