Carbon dioxide induced panic attacks and short term clonazepam treatment. Preliminary study.
OBJECTIVE
1. To verify the sensibility of panic patients to a mixture of 35% CO2 and 65% O2. 2. To determine if a ten days treatment with clonazepam attenuates the panic attacks induced by the inhalation of 35% carbon dioxide in panic disorder.


METHODS
We randomly selected six panic disorder subjects, using the Structured Clinical Interview for DSM-IV. All subjects went double-blindly through an inhalation of 35% CO2 and compressed gas (atmospheric air) on two occasions. First, at baseline, when they were drug free. Second, after a 10 days clonazepam treatment.


RESULTS
Neither at baseline nor after treatment any patient had a panic attack during compressed gas inhalation. At the first test five patients (83.3%) had a severe panic attack with high levels of subjective anxiety during carbon dioxide inhalation. After 9.6 (+/- 3.4) days of clonazepam treatment, only two (33.3%) patients experienced a mild panic attack.


CONCLUSIONS
This pilot study suggests the efficacy of the short term clonazepam therapy in attenuating panic attacks and supports the usefulness of the 35% carbon dioxide challenge test as an analogue method for study the efficacy of anti-panic drugs. Further placebo-controlled studies to pharmacological treatment are warranted.
Nardi
A E
AE
Laboratory of Panic and Respiration, Anxiety and Depression Research Program, Federal University of Rio de Janeiro, Brazil. aenardi@novanet.com.br
Valença
A M
AM
Zin
W
W
Nascimento
I
I
D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use*; D002245:Carbon Dioxide / Q000009:adverse effects*; D002998:Clonazepam / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016584:Panic Disorder / Q000139:chemically induced* / Q000188:drug therapy*; D013997:Time Factors
D000927:Anticonvulsants; D002245:Carbon Dioxide; D002998:Clonazepam