Antidepressant

The antidepressant effect of sertraline is presumed to be linked to its ability to inhibit the neuronal reuptake of serotonin. It has only very weak effects on norepinephrine and dopamine neuronal reuptake. At clinical doses, sertraline blocks the uptake of serotonin into human platelets.

Like most clinically effective antidepressants, sertraline downregulates brain norepinephrine and serotonin receptors in animals. In receptor binding studies, sertraline has no significant affinity for adrenergic (alpha(1), alpha(2) and beta), cholinergic, GABA, dopaminergic, histaminergic, serotonergic (5-HT1A, 5-HT1B, 5-HT2) or benzodiazepine binding sites.

In placebo-controlled studies in normal volunteers, sertraline did not cause sedation and did not interfere with psychomotor performance.

Pharmacokinetics:
Following multiple oral once-daily doses of 200 mg, the mean peak plasma concentration (C(max)) of sertraline is 0.19 mcg/mL occurring between 6 to 8 hours post-dose. The area under the plasma concentration time is 2.8 mg hr/L. For desmethylsertraline, C(max) is 0.14 mcg/mL, the half-life 65 hours and the area under the curve 2.3 mg hr/L. Following single or multiple oral once-daily doses of 50 to 400 mg/day the average terminal elimination half-life is approximately 26 hours. Linear dose proportionality has been demonstrated over the clinical dose range of 50 to 200 mg/day.

Food appears to increase the bioavailability by about 40%: it is recommended that sertraline be administered with meals.

Sertraline is extensively metabolized to N-desmethylsertraline, which shows negligible pharmacological activity. Both sertraline and N-desmethylsertraline undergo oxidative deamination and subsequent reduction, hydroxylation and glucuronide conjugation. Biliary excretion of metabolites is significant.

Approximately 98% of sertraline is plasma protein bound. The interactions between sertraline and other highly protein bound drugs have not been fully evaluated (see Precautions).

The pharmacokinetics of sertraline itself appear to be similar in young and elderly subjects. Plasma levels of N-desmethylsertraline show a 3-fold elevation in the elderly following multiple dosing, however, the clinical significance of this observation is not known.