To the Editor: Pramipexole is a new compound that shows selectivity for presynaptic dopamine autoreceptors of types 2 and 3 and has recently been approved for the treatment of Parkinson’s disease (1). Reports have suggested its possible effectiveness in treating other neuropsychiatric conditions, such as depressive phases of bipolar disorder that do not respond to conventional treatments (2), the negative symptoms of schizophrenia (3), and craving in cocaine abusers (4). In this report, we comment on two patients suffering from panic disorder with agoraphobia who showed marked improvement after their treatment was augmented with pramipexole.
Ms. A, a 48-year-old woman, had a lifetime history of panic disorder with concomitant severe agoraphobia that provoked significant behavioral limitations. Previously, she had been treated with anxiolytics and had responded poorly. She had only in the last 10 years been treated with tricyclics and selective serotonin reuptake inhibitors (SSRIs), all at adequate doses and duration, but she experienced only a partial response. Lithium salts, opipramol, buspirone, valproate, and gabapentin were prescribed as augmentation treatments, but they had no effect on her agoraphobic avoidance.
Although Ms. A’s neurovegetative symptoms were well controlled with a combination of paroxetine and gabapentin, an adjunctive trial of pramipexole was begun at a dose of 0.25 mg/day and titrated up to 1.5 mg/day during the following 3 weeks. Side effects were not significant, except for an initial and transient mild nausea. In this phase of treatment, a progressive reduction of her agoraphobic fears was observed; this improvement continued throughout Ms. A’s 8-month follow-up. Furthermore, during this period she did not suffer any panic attacks.
Mr. B, a 32-year-old man, had suffered his first panic attack 5 years previously during a car trip. This first episode was followed by others within a few weeks. These were so severe that he was soon unable to travel alone. After 3 months he consulted a psychiatrist, who prescribed imipramine, which he could not tolerate because of dry mouth, constipation, and especially, blurred vision, which interfered excessively with his work as a designer and painter. Different SSRIs and mirtazapine were prescribed, but all of these caused mydriasis. Nefazodone, venlafaxine, reboxetine, valproate, and carbamazepine were all tolerated, but none of them produced any improvement in his panic symptoms. As a result, Mr. B underwent EEG, computerized tomography scanning, and magnetic resonance imaging, the results of which were negative. In more recent months he has complained of difficulty moving his right hand properly and also of tremors, which led him to become depressed and convinced that he would never recover.
Pramipexole was prescribed at an initial dose of 0.25 mg/day, which was increased to 1 mg/day within a month. Mr. B experienced no side effects, and after 1 month of this regimen, for the first time in 5 years, he reported a decrease in the frequency of his panic attacks and anticipatory anxiety. This improvement continued throughout the following 6 months. Mr. B is now free of somatic symptoms and is able to drive alone.
These two case reports indicate the possible use of pramipexole in the treatment of resistant panic disorder and suggest the need for further confirmation of its efficacy in controlled trials.