Behavioral and developmental changes in rats with prenatal exposure of mirtazapine

Mirtazapine is an often used antidepressant drug; however insufficient information is available regarding its safety during pregnancy. Therefore, this work was initiated to study the effect of prenatal exposure of mirtazapine on postnatal developments of rats. The study was conducted on pregnant rats to observe the safety profile of mirtazapine in comparison to control. The percentage weight gain, gestation period and litter size of the rats treated with double therapeutic dose (DTD) was significantly lower than the rats treated with therapeutic dose (TD) and rats of control group. However the litter size of the TD treated rats was also found smaller than the control. The offspring were examined through battery of test in order to evaluate their developmental neurotoxicity. The test includes the assessment of postnatal growth, reflex ontogeny, neuromotor abilities, activity level, emotional reactivity and learning ability. The DTD exposure negatively affected on overall growth of pups in comparison to TD exposed pups and control group. Further, the amine concentration in brain was also found significantly lower in DTD exposed pups. Therefore, this study reveals that the treatment of pregnant rats with TD and DTD decreases their litter size. In addition the prenatal exposure of DTD of mirtazapine negatively affects on neurodevelopment of rats.