Mirtazapine Induced Tardive Akathisia: A Case Report

Aims: Akathisia is a side effect generally associated with antipsychotic drugs. However, akathisia is also reported as a side effect of antidepressants, especially of the selective serotonin reuptake inhibitor group. Mirtazapine is an antidepressant that has a special role in relation with akathisia. There have been randomized controlled studies reporting that mirtazapine is effective in treatment of antipsychotic-induced akathisia. However, there have also been few cases in which acute akathisia are induced by mirtazapine. We would like to report a case of mirtazapine induced tardive akathisia. Case report: Mrs. A is a 43-year old woman who applied to psychiatrist four years ago for complaints such as depressive mood, anhedonia, reduced sleep and poor appetite. She was diagnosed as having a major depressive disorder and prescribed 15 mg mirtazapine at night. Mrs. A benefited from the treatment within 1-2 months, complied with medication but did not attend follow-up examinations. About a year later, she started to have severe restlessness, shaking and need to move about one hour after mirtazapine intake. Therefore, patient started use mirtazapine once every three days for the following three years. Akathisia starting after mirtazapine intake disappeared about 8-10 hours later and patient did not have akathisia during two days that she did not have mirtazapine intake. Conclusion: Mirtazapine might be effective both in treatment and precipitation of akathisia. These effects might be determined by multiple interactions among factors such as duration of mirtazapine treatment, presence of concomitant treatment, neurological basis of the disorder.