Urinary 6-sulfatoxymelatonin (aMT6s) excretion can act as a biomarker for predicting a positive therapeutic response to fluoxetine, according to results published in Therapeutic Advances in Psychopharmacology.
Previous studies have shown that acute fluoxetine treatment enhances serotonin within the pineal gland, possibly leading to an increase in the synthesis of melatonin, which is metabolized to aMT6s at night.
The study cohort consisted of 20 women (mean age 40.19±3.76 years) with a diagnosis of major depressive disorder. The researchers used the Beck Depression Inventory (BDI) to assess depressive symptoms. At the start of the study, participants took 20 mg of fluoxetine every morning. The dose could be increased by 20 mg every 4 weeks until symptom remission was achieved. The aMT6s concentration was evaluated in overnight urine samples collected 1 day before and 1 day after the first fluoxetine dose with use of an enzyme immunoassay.