Inhibition of serotonin uptake by optical isomers of fluoxetine

The optical isomers of fluoxetine, a selective inhibitor of serotonin (5‐hydroxytryptamine, 5HT) uptake, have been compared pharmacologically. As inhibitors of 3 H‐5HT uptake in cortical synaptosomes and of 3 H‐fluoxetine binding in cortical membranes, the (+)‐isomer of fluoxetine was slightly more potent than the (−)‐isomer. The potencies to inhibit 3 H‐5HT uptake ex vivo in synaptosomal preparations of cerebral cortex and brain stem were about the same, except that the (−)‐isomer had a much shorter duration of action than the (+)‐isomer in rats.