Biomedical subjects

W Zin

Publications and source records attributed to W Zin.

4 recordsLinked to original sources

PubMed2000

Double-blind clonazepam vs placebo in panic disorder treatment.

OBJECTIVE: To assess the effectiveness of clonazepam, in a fixed dose (2 mg/day), compared with placebo in the treatment of panic disorder patients. METHOD: 24 panic disorder patients with agoraphobia were randomly selected. The diagnosis was obtained using the structured clinical interview for DSM-IV. All twenty-four subjects were randomly assigned to either treatment with clonazepam (2 mg/day) or placebo, during 6 weeks. Efficacy assessments included: change from baseline in the number of panic attacks; CGI scores for panic disorder; Hamilton rating scale for anxiety; and panic associated symptoms scale. RESULTS: At the therapeutic endpoint, only one of 9 placebo patients (11.1%) were free of panic attacks, compared with 8 of 13 (61.5%) clonazepam patients (Fisher exact test; p=0,031). CONCLUSION: the results provide evidence for the efficacy of clonazepam in panic disorder patients.

Adult↗

PubMed1999

Carbon dioxide induced panic attacks and short term clonazepam treatment. Preliminary study.

AIMS: 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. METHOD: 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. CONCLUSION: 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.

Adolescent↗

PubMed1999

Panic disorder and hyperventilation.

UNLABELLED: Respiratory abnormalities are associated with anxiety, particularly with panic attacks. Symptoms such as shortness of breath, "empty-head" feeling, dizziness, paresthesias and tachypnea have been described in the psychiatric and respiratory physiology related to panic disorder. Panic disorder patients exhibit both behaviorally and physiologically abnormal responses to respiratory challenges tests. OBJECTIVE: We aim to observe the induction of panic attacks by hyperventilation in a group of panic disorder patients (DSM-IV). METHOD: 13 panic disorder patients and 11 normal volunteers were randomly selected. They were drug free for a week. They were induced to hyperventilate (30 breaths/min) for 3 minutes. Anxiety scales were taken before and after the test. RESULTS: 9 (69.2%) panic disorder patients and one (9.1%) of control subjects had a panic attack after hyperventilating (p < 0.05). CONCLUSION: The panic disorder group was more sensitive to hyperventilation than normal volunteers. The induction of panic attacks by voluntary hyperventilation may be a useful and simple test for validating the diagnosis in some specific panic disorder patients.

Adult↗

PubMed1985

Respiratory resistance in dogs by the single-breath and the forced oscillation methods.

Total respiratory resistance (Rrs) was measured in six anesthetized dogs with two different methods: the single-breath (SB) method, which provides the time constant of the system during a relaxed expiration and the forced oscillation (FO) method, which uses a pseudorandom noise signal applied at the airway opening. The comparison was made in three conditions: before muscle paralysis (A), after muscle paralysis (B), and after tracheal banding (C). In conditions A and B the two computed resistances correlated very well with each other (r = 0.98). No systematic difference between Rrs values obtained with the two methods was found. In condition C the respiratory resistance was clearly nonlinear from the flow-volume curves during SB and could be described with Rohrer's equation: Rrs = K1 X V + K2 X V2, where K1 and K2 are Kohrer's constant and V is flow. Rrs measured with FO was not frequency dependent during tracheal banding (C) and was virtually equivalent to K1. Since the FO method uses low flows as the input of the respiratory system and K1 could be ascribed to laminar flow, the numerical matching appears reasonable and tends to reinforce the validity of both methods of measurement. We conclude that, for the normal respiratory system, FO and SB methods are approximately equivalent. In the presence of a markedly alinear central airway resistance with normal lungs, the SB method appears to provide a more adequate description of the flow-resistive properties of the system.

Airway Resistance↗