Carbon dioxide induced panic attacks and short term clonazepam treatment: preliminary study

RESUMO

AIMS: 1. To verify the sensibility of panic patients to a mixture of 35 per cent CO2 and 65 per cent O2. 2. To determine if a ten days treatment with clonazepam attenuates the panic attacks induced by the inhalation of 35 per cent carbon dioxide in panic disorder. METHOD: We randomly selected six panic disorder subjects, using the Structured Clinical Interview ofr DSM-IV. All subjects went double-blindly through an inhalation of 35 per cent 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 per cent) 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 per cent) patients experienced a mild panic attack. CONCLUSION: This pilot study suggests the efficacy of the short term clonazepam therapy in attenuating panic attacks and supports the usefulness of the 35 per cent 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.