Pentoxifylline as a Novel Add-on Therapy for Major Depressive Disorder in Adult Patients: A Randomized, Double-Blind, Placebo-Controlled Trial

Background Evidence indicates an association between immune dysregulation and major depressive disorder (MDD). Pentoxifylline (PTX), a phosphodiesterase inhibitor, has been shown to reduce pro-inflammatory activities. The aim of this study was to evaluate changes in depressive symptoms and pro-inflammatory markers after administration of PTX as an adjunctive agent to citalopram in patients with MDD. Methods One hundred patients were randomly assigned to either citalopram (20 mg/day) plus placebo (twice daily) (n=50) or citalopram (20 mg/day) plus PTX (400 mg) (twice daily) (n=50). The Hamilton Depression Rating Scale-17 (HAM-D-17) scores at baseline, weeks 2, 4, 6, 8, 10, and 12 and serum levels of interleukin1-beta (IL-1-beta), tumor necrosis factor-alpha, C-reactive protein, IL-6, serotonin, IL-10, and brain-derived neurotrophic factor (BDNF) at baseline and week 12 were evaluated. Results HAM-D-17 score in the PTX group significantly reduced in comparison to the control group after weeks 4, 6, 8,10, and 12 ((LSMD): - 2.193, p=0.021; - 2.597, p=0.036; - 2.916, p=0.019; - 4.336, p=0.005; and - 4.087, p=0.008, respectively). Patients who received PTX had a better response (83%) and remission rate (79%) compared to the placebo group (49% and 40%, p=0.006 and p=0.01, respectively). Moreover, the reduction in serum concentrations of pro-inflammatory factors and increase in serotonin and BDNF in the PTX group was significantly greater than in the placebo group (p<0.001). Conclusion These findings support the safety and efficacy of PTX as an adjunctive antidepressant agent with anti-inflammatory effects in patients with MDD.