Sir: Discontinuation symptoms associated with abrupt cessation of antidepressant medications including tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), and selective serotonin reuptake inhibitors (SSRIs) are widely reported in the literature.1 To date, there is only one published report of withdrawal symptoms associated with mirtazapine.2 A case is presented herein of a patient who experienced withdrawal symptoms associated with the sudden discontinuation of mirtazapine.
Case report. Ms. A, a 25-year-old woman, was diagnosed with a major depressive episode, moderate and panic disorder without agoraphobia according to DSM-IV. She was taking mirtazapine, 60 mg/day, as well as clonazepam, 0.5 mg b.i.d. She was doing well until she had to go out of town unexpectedly due to a family emergency. Toward the end of her stay, she ran out of mirtazapine and within 48 hours began to notice anxiety, restlessness, irritability, nausea, vomiting, and insomnia. She continued taking clonazepam and did not experience any panic attacks. Upon her return, Ms. A was evaluated and restarted on mirtazapine therapy at her usual dose. Her symptoms completely resolved within 24 hours. At 3 months, she remains stable.
Sudden withdrawal from antidepressants can cause a variety of somatic and psychological symptoms.3 Although the exact mechanism is not fully known, a state of serotonin dysregulation may play a role.4 Schatzberg et al.5 postulate that other neurotransmitters such as dopamine, norepinephrine, and γ-aminobutyric acid (GABA) may be involved, as well as cholinergic rebound. A state of dysregulation of both the serotonin and noradrenergic systems may have been involved in this particular case, given the pharmacologic profile of mirtazapine of enhancing both serotonergic and noradrenergic transmission.6 Because sudden or abrupt cessation of antidepressant therapy can lead to a withdrawal or discontinuation syndrome, clinicians need to be aware of this possibility. Although the syndrome is time-limited, the symptoms can be troublesome to patients as well as contribute to decreased compliance, leading to unnecessary visits.
Conclusions and opinions expressed are those of the author and do not necessarily reflect the position or policy of the U.S. Government, Department of Defense, Department of the Army, or the U.S. Army Medical Command.
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