MITAPREX 7.5MG is a tablet containing 7.5 milligrams of mirtazapine. 1 Mirtazapine is an antidepressant medication classified as a tetracyclic antidepressant. 2 It is used in the treatment of major depressive disorder. This medication works by affecting the levels of specific neurotransmitters in the brain, notably norepinephrine and serotonin, which can contribute to improvements in mood, anxiety, sleep patterns, and appetite. 3 The lower 7.5mg dose might be used as an initial dose or for certain individuals who may be more sensitive to the effects of the medication.