Absolute bioavailability and stereoselective pharmacokinetics of doxepin

@article{Yan2002AbsoluteBA,
  title={Absolute bioavailability and stereoselective pharmacokinetics of doxepin},
  author={J.-H. Yan and John W. Hubbard and Gordon Mckay and Elarien D. Korchinski and Kamal K. Midha},
  journal={Xenobiotica},
  year={2002},
  volume={32},
  pages={615 - 623}
}
1. Commercial doxepin contains geometric isomers in the proportions Z : E = 15:85. Z -doxepin and its metabolite Z - N -desmethyldoxepin are both active antidepressants, whereas the corresponding E -isomers are less active therapeutically. 2. The present pharmacokinetic study was a balanced, randomized, two-treatment, two-period, two-sequence crossover design in which 12 healthy male volunteers were given single doses of commercial doxepin intravenously and orally on two occasions separated by… 

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    Biochemical pharmacology
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It is found that significantly higher levels of desmethyldoxepin and of total drug are detected in plasma when the two isomers are separated and measured by method 2, and it is suggested that in future studies correlating plasma levels and the clinical effects of doxepin, both the cis- and trans-isomers of doXepin be determined.

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