Pharmacokinetic comparison of a delayed-release combination of doxylamine succinate and pyridoxine hydrocholoride (Diclectin) and oral solutions of these drugs in healthy women of childbearing age.
BACKGROUND
The delayed-release combination of doxylamine succinate and pyridoxine hydrochloride was the most commonly used antiemetic (Bendectin) approved by FDA for nausea and vomiting of pregnancy (NVP) until its removal of the market in 1983. The drug is widely used today in Canada (Diclectin). The pharmacokinetics of Diclectin has never been described in humans.


OBJECTIVE
To compare the pharmacokinetics of Diclectin to oral solutions of its two components.


METHODS
A randomized, cross over, open label design, comparing the pharmacokinetics of Diclectin to those of the oral solutions of the two components in 18 healthy adult, non pregnant women of childbearing age.


RESULTS
Diclectin exhibited similar oral bioavailability to those of the oral solutions. In contrast, the time-to-peak, (Tmax), reflecting the rate of absorption, was 3-6 times longer for the two components of the delayed-release drug confirming its delayed-release characteristics.


CONCLUSIONS
The pharmacokinetic profile of Diclectin well explains its documented delayed efficacy.
Nulman
Irena
I
The Motherisk Program, Division of Clinical Pharmacology & Toxicology, The Hospital for Sick Children, Toronto, Canada.
Koren
Gideon
G
D000328:Adult; D000932:Antiemetics / Q000008:administration & dosage / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001682:Biological Availability; D018592:Cross-Over Studies; D003692:Delayed-Action Preparations; D004319:Doxylamine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D004338:Drug Combinations; D005260:Female; D006801:Humans; D011247:Pregnancy; D011730:Pyridoxal / Q000493:pharmacokinetics; D011732:Pyridoxal Phosphate / Q000493:pharmacokinetics; D011736:Pyridoxine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D012996:Solutions; D013607:Tablets
D000932:Antiemetics; D003692:Delayed-Action Preparations; D004338:Drug Combinations; D012996:Solutions; D013607:Tablets; D011730:Pyridoxal; D011732:Pyridoxal Phosphate; D004319:Doxylamine; D011736:Pyridoxine; C035385:doxylamine succinate