Letters to the Editor
Respiratory Panic Disorder Treatment With Clonidine
Dear Editor:
Clonidine is known to block alpha-2 receptors in the locus coeruleus, and for theoretical reasons, it would seem a good antipanic drug. Few clinical trials have been conducted with clonidine for the treatment of panic disorder (PD) (1,2). In a small series, two-thirds of patients initially responded, but the therapeutic effect tended to be lost in some weeks, despite continuation of dosage (1). In this study, we report 2 cases of respiratory PD patients who were successfully treated with clonidine in the Laboratory of Panic and Respiration of Rio de Janeiro.
Case Report 1
Miss A is a white student, age 20 years. The patient began having panic attacks 3 years ago, with symptoms including sweating, shivering, tachycardia, dyspnea, and an intense fear lasting from 5 to 20 minutes. Two months before her first evaluation, the patient suffered new panic attacks with feelings of dyspnea, shortness of breath, tachycardia, fear of choking, and fear of dying. She described a fear of being home alone and of riding buses or other public transportation; she therefore avoided these situations. She underwent several laboratory examinations, all with normal results. She was initially treated with 0.15 mg daily of clonidine. After 6 weeks, she was taking 0.30 mg daily of clonidine and achieved full remission of the panic attacks and phobic avoidance. In the initial 2 weeks of treatment, the patient described feelings of mild dizziness and nausea.
Case Report 2
Miss C is a white college student, age 23 years. The patient described recurrent panic attacks during a 1-year period, with feelings of dizziness, tachycardia, trembling, heat spells, dyspnea, and a fear of becoming insane (lasting 10 to 15 minutes). The panic attacks occurred mainly in closed places, such as restaurants and bookstores. The patient discovered that by avoiding these situations she could decrease the frequency of the panic attacks, and she progressively interrupted all daily activities until she seldom left the house at all and developed an agoraphobic behaviour. Laboratory and clinical exams were normal. She was initially treated with 0.15 mg daily of clonidine, increased to 0.30 mg daily after 4 weeks of treatment, which fully remitted her panic attacks. At the sixth week of treatment, the patient continued her studies with the same dosage of 0.30 mg daily of clonidine. She described feelings of somnolence in the initial 2 weeks of treatment.
Both patients obtained panic-free status, reduced anxiety levels, and better functioning after clonidine administration for 6 weeks. An interesting finding is the remission of panic attacks with clonidine as early as the 4th week of treatment. Clonidine was well tolerated by the patients. All patients were classified as respiratory PD subtype, according to Briggs and colleagues’ criteria (3). This subtype may have a favourable clinical response to clonidine. Because of its specific adrenergic action, clonidine may be an effective tool for investigating and elucidating abnormalities in a noradrenergic system in patients with PD, and it may play a role in relieving symptoms of anxiety caused by noradrenergic hyperactivity.
References
1. Liebowitz MR, Fyer AJ, Mcgrath P, Klein DF. Clonidine treatment of panic disorder. Psychopharmacol Bull 1981;17:122–3.
2. Uhde TW, Stein MB, Vittone BJ, Siever LJ, Boulenger JP, Klein E, and others. Behavioral and physiologic effects of short-term and long-term administration of clonidine in panic disorder. Arch Gen Psychiatry 1989;46;170–77.
3. Briggs AC, Stretch DD, Brandon S. Subtyping of panic disorder by symptom profile. Br J Psychiatry 1993;163:201–9.
Alexandre M Valença, MD, PhD
FMarco A Mezzasalma, MD
Isabella Nascimento, MD, MSc
Fabiana L Lopes, MD
Walter A Zin, MD, PhD
Antonio E Nardi, MD, PhD
Rio de Janeiro, Brazil
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