Therapeutic monitoring of escitalopram by dexamethasone suppression test

Depression is associated with a dysfunction of regulation of the hypothalamic-pituitary-adrenal, HPA, which is reflected in the alteration of the dexamethasone suppression test, DST. Escitalopram and other SSRIs decrease the HPA axis response to the DST, beeing the aim of this study validate the DST as a surrogate marker of central serotonergic activity in the treatment with escitalopram and its application to the calculation of the dosage regimens.

Prospective observational study on 29 patients, upon whom was performed the DST-test with 0.25 mg of Dexamethasone and subsequent genetic analysis of CYP2C19 by Progenika PHARMAchip test.

The range of plasma cortisol levels post-DTS associated with each phenotypic group were: PM phenotype= 0.6 to 1.7 mcg/dl, IM phenotype= 1.2 to 3.5 mcg/dl and EM phenotype = 4.8 to 13.2 mcg/dl, being carried out the dose titration and correspondng, respectively, the following dose regimens: 3-4 mg/day, 5-8 mg/day and 10-31 mg/day. COCLUSIONES: It has been shown that the DST test can be used as a surrogate marker of drug response to escitalopram and as a tool for dose adjustment, providing significant data on different phenotypes of CYP2C19 metabolizers.