Pharmacokinetics
Sertraline is absorbed slowly when taken orally, achieving its maximal concentration in the plasma 4–6 hours after ingestion. In the blood, it is 98.5% bound to plasma proteins. Its half-life in the body is 13–45 hours and, on average, is about 1.5 times longer in women (32 hours) than in men (22 hours), leading to a 1.5-times-higher exposure in women. According to in vitro studies, sertraline is metabolized by multiple cytochrome 450 isoforms: CYP2D6, CYP2C9, CYP2B6, CYP2C19 and CYP3A4. It appeared unlikely that inhibition of any single isoform could cause clinically significant changes in sertraline pharmacokinetics. No differences in sertraline pharmacokinetics were observed between people with high and low activity of CYP2D6; however, poor CYP2C19 metabolizers had a 1.5-times-higher level of sertraline than normal metabolizers. In vitro data also indicate that the inhibition of CYP2B6 should have even greater effect than the inhibition of CYP2C19, while the contribution of CYP2C9 and CYP3A4 to the metabolism of sertraline would be minor. These conclusions have not been verified in human studies. Sertraline can be deaminated in vitro by monoamine oxidases; however, this metabolic pathway has never been studied in vivo. The major metabolite of sertraline, desmethylsertraline, is about 50 times weaker as a serotonin transporter inhibitor than sertraline and its clinical effect is negligible.
Non-amine metabolites may also contribute to the antidepressant effects of this medication. Sertraline deaminated is O-2098, a compound that has been found to inhibit the dopamine reuptake transporter proteins in spite of its lack of a nitrogen atom.
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