The Efficacy of Combination Therapy With SWTX Capsule and Paroxetine for Depression: A Randomized Controlled Trial

Depression, a leading global cause of disease burden, often shows limited response and notable adverse reactions to existing antidepressants. Exploring combination therapies is therefore crucial to enhance therapeutic efficacy and improve safety. Consequently, this study aimed to explore the alterations in blood concentration, therapeutic effect, and safety of San Wei Tan Xiang (SWTX) capsule in combination with paroxetine for the treatment of patients suffering from depression.

Seventy-six patients fulfilling the diagnostic criteria for depression were enrolled in this randomized controlled trial and randomly divided into a Combination Therapy Group (paroxetine plus SWTX capsule) and a Monotherapy Group (paroxetine alone). Paroxetine blood concentrations and the Treatment Emergent Symptom Scale (TESS) were measured at the second, fourth, and eighth weeks. The 24-item Hamilton Depression Rating Scale (HAMD-24) and the Montgomery Asberg Depression Rating Scale (MADRS) assessed depressive symptoms at baseline and the second, fourth, and eighth weeks.

In the eighth week, the blood paroxetine concentration in the Monotherapy Group was markedly elevated compared to the Combination Therapy Group (p = 0.001). During the fourth and eighth week, the HAMD-24 scores of the Combination Therapy Group were notably lower compared to the Monotherapy Group (p < 0.001). In the second, fourth, and eighth week, the Combination Therapy Group demonstrated a superior HAMD score reduction rate (p < 0.001). By the eighth week, the MADRS scores had dropped significantly lower in the Combination Therapy Group compared to the Monotherapy Group (p < 0.001). And in the eighth week, the Combination Therapy Group had a lower rate of adverse events than the Monotherapy Group, as evaluated by TESS.

Combining SWTX capsule with paroxetine might help maintain paroxetine blood concentration within the optimal range of 20-65 ng/mL, which could potentially lead to better alleviation of depressive symptoms and may reduce adverse reactions compared to paroxetine monotherapy, possibly enhancing overall treatment safety. Trial Registration: Trial was registered in the China Registry of Clinical Trials (Registration ChiCTR2500110909).