Effects of low-dose olanzapine on duloxetine-related nausea and vomiting for the treatment of major depressive disorder.

Objective: This study aims to investigate the effects of low-dose olanzapine on preventing occurrence and controlling the severity of nausea and vomiting related to duloxetine in treating major depressive disorder.
Methods: Two hundred sixty-eight subjects with major depressive disorder were divided into control and trial groups. The control group had 165 subjects and was treated with duloxetine only, whereas the trial group had 103 subjects and received duloxetine combined with low-dose olanzapine. After the treatment for 2 weeks, both groups were evaluated for occurrence and severity of adverse effects on digestive tract using the Treatment Emergent Symptom Scale.
Results: The trial group, scored at 13, showed significantly less occurrence and severity of nausea and vomiting than the control group, scored at 38 (P < 0.05). The occurrence of nausea and vomiting in the trial group is significantly lower compared with that in the control group, and the occurrence decreases as the dose of olanzapine increases (P < 0.05). The antiemetic effect of olanzapine is valid to all subjects who received it.
Conclusions: Duloxetine combined with low-dose olanzapine can effectively reduce the occurrence and severity of duloxetine-related nausea and vomiting. With the increase of olanzapine dose, the antiemetic effect becomes stronger. Olanzapine is a safe and efficient drug for the prevention of duloxetine-related nausea and vomiting.