Long Term & Short Term Dose Dependent Effect of Mirtazapine- A Case Report

Mirtazapine is considered to be safest and versatile antidepressant. However, sedation is known to be dose dependent side effect. 7.5 mg/day mirtazapine induces more sedation than 15 mg/day mirtazapine. There is no other side effect of mirtazapine which is reported to be dose dependent. Case Report: Here is a case, where dose dependent effect and side effect is detected. A 38-year-old married female reported with array of recurring symptoms like dysphoria, insomnia, loss of appetite, burning all over, uneasiness, increased frequency of micturation and stool, irritability, frustration, weeping often. She was symptomatic since last five to six years, despite regular psychiatric treatment. Her earlier psychiatrist had expressed inability to treat recurrence and intensity of her symptoms. She was kept on mirtazapine 7.5 mg per day to begin with. She responded favorably. Dose of mirtazapine was increased to 15 mg/day to optimize the standardization of dose. Optimum standard dose should be given to achieve optimum, long lasting effects and recovery. Within one to two days she complained of inability to pass urine. Her complaint was specific that she was not able to empty her bladder completely. After completing the act of micturation she used to experience much discomfort in pelvic region. Further investigations revealed significant urinary retention. Lowering of dose brought her relief immediately. Follow up for three years now reveals that patient is asymptomatic with the dose of 7.5mg Mirtazapine. It is remarkable to find Single antidepressant mirtazapine has given long lasting asymptomatic status, despite previous use of multiple antidepressants. Conclusion: Mirtazapine with dose of 7.5 mg per day effectively could treat recurring symptoms of a female patient and offered steady asymptomatic clinical picture. Increase in dose up to 15 mg/day caused significant side effect of urinary retention against the conventional belief of rise in dose of mirtazapine would increase the relief.