Phenelzine for Treatment-Resistant Panic Disorder

Vice-Chair, Clinical Services, Department of Psychiatry, NYU Medical Center

The only medications currently FDA approved for panic disorder are fluoxetine, sertraline, paroxetine, venlafaxine, alprazolam, and clonazepam. Some data exists, however, demonstrating the efficacy of phenelzine for panic disorder and phobic anxiety. Now comes the first published report of the successful use of phenelzine for severe, treatment-resistant panic disorder with agoraphobia.

The Case

A 45 year-old computer engineer with poorly controlled panic disorder presented for outpatient treatment in 2005 complaining of 2 panic attacks per day, each characterized by the sudden onset of extreme anxiety, diaphoresis, derealization, abdominal distress, and fear of losing control. The symptoms peaked 15 minutes after onset and lasted one hour, with residual anxiety lasting most of the day. His panic attacks had started 5 years earlier and had been at the presenting severity level for 2 years. He denied use of alcohol, coffee, tobacco, illegal drugs, or of any other anxiogenic herbal or over-the-counter products. At the time of presentation, his medication regimen consisted of paroxetine 20 mg qAM, mirtazapine 30 mg qHS, clonazepam 1 mg bid, alprazolam 1 mg qid, and metoprolol XL 200 mg qD, prescribed for hypertension.

After the initial evaluation, mirtazapine was discontinued and the dose of paroxetine was increased to 60 mg qD for the next 6 weeks. The patient learned deep-breathing exercises. While alprazolam was discontinued, clonazepam was increased, to 1 mg qid. Subsequently, the patient’s panic and general anxiety symptoms significantly worsened. Eventually, he was placed on alprazolam 1 mg qid, clonazepam 1 mg tid, and gabapentin 1,200 mg tid, which brought him back to a relative baseline of minimal functioning. Paroxetine was then tapered as follows: 40 mg/day for 7 days then 20 mg/day for 7 days then discontinuation. Two weeks after the last dose of paroxetine, phenelzine 15 mg/day was initiated, then increased over 9 days to a target dose of 15 mg qid.

Within 4 days of treatment with phenelzine 15 mg qid, the patient’s panic attack frequency decreased to one panic attack every other day, the lowest rate he had experienced in 2 years. Subsequently, the panic attacks continued to diminish. At last follow-up, the patient reported being free of panic attacks for the prior 2 months, his longest period of sustained remission. He also denied experiencing any symptoms of agoraphobia. He continued to take, in addition to phenelzine 15 mg qid, alprazolam 0.25 mg qHS, clonazepam 0.5 mg qAM, and gabapentin 1,200 mg tid.

Conclusion

The case reported here suggests that phenelzine may be a useful medication for treatment-resistant or treatment-refractory panic disorder. As was true for the patient described, adjunctive medication, and psychotherapy, may also be required to achieve full remission.

Disclosure: Dr. Ginsberg is a speaker for AstraZeneca, Cyberonics, Forest, and GlaxoSmithKline; and has received research support from Cyberonics.