About Fluoxetine Selective Serotonin Reuptake Inhibitor, Antidepressant. Mechanism of Action of Fluoxetine Fluoxetine preferentially inhibits the re-uptake of Serotonin (5 HT) in the CNS nerve terminals .This will result in an increased concentration of neurotransmitter Serotonin in the synaptic cleft and produces antidepressant effect. Fluoxetine has only less affinity towards Dopaminergic, Cholinergic and Adrenergic receptors. Interactions for Fluoxetine MAOIs: Serious life threatening reactions. At least 14 days should elapse after MAOIs withdrawal and initiation of fluoxentine. At least 5 weeks should elapse after fluoxentine withdrawal and initiation of the therapy with MAOIs. Diazepam: Half-life of diazepam prolonged. Haloperidol: Chances of severe extrapyramidal reactions. Lithium: Serum lithium levels increased leading to toxicity. TCAs: Efiicacy and toxic effects of TCAs enhanced. Warfarin,