Pharmacogenetic study focused on fluoxetine pharmacodynamics in children and adolescent patients: impact of the serotonin pathway.

OBJECTIVE: Pharmacogenetic studies of fluoxetine in children and adolescents are scarce. After reporting the effect of genetic variants in genes related to the fluoxetine pharmacokinetics on clinical response in a pediatric population, we now evaluate the impact of genetic markers involved in its pharmacodynamics.

PATIENTS AND METHODS: The assessment was performed in 83 patients after 12 weeks of fluoxetine treatment. The genetic association analysis included a total of 316 validated single nucleotide polymorphisms in 45 candidate genes involved in six different pathways.

RESULTS: Clinical improvement after treatment with fluoxetine in our pediatric population was associated significantly with two polymorphisms located in genes related to the serotonergic system: the 5-hydroxytryptamine receptor 1B (HTR1B) and the tryptophan 5-hydroxylase 2 (TPH2).

CONCLUSION: Although a wide range of candidate genes related to different pathways were assessed, the results show that genetic markers directly related to serotonin have an important effect on fluoxetine response.