Simon, S.T., Higginson, I.J., Booth, S., Harding, R., & Bausewein, C. (2010). Benzodiazepines for the relief of breathlessness in advanced malignant and non-malignant diseases in adults. Cochrane Database of Systematic Reviews (Online), 1(1), CD007354.

The primary aim of the study was to determine the efficacy of benzodiazepines for the relief of breathlessness in patients with advanced disease. The secondary aim was to determine the efficacy of different benzodiazepines, different doses of benzodiazepines, different routes of benzodiazepines, adverse effects of benzodiazepines, and the efficacy in different groups for the relief of breathlessness .

Databases searched were the Cochrane Pain, Palliative, and Supportive Care Trials Register (September 2009), Cochrane Central Register of Controlled Trials (Central) in the Cochrane Library (September 2009), Cochrane Database of Systematic Reviews in the Cochrane Library (September 2009), Database of Abstracts or Reviews of Effectiveness (September 2009), MEDLINE (1950–2009), EMBASE (1980–1989 and 2009), CINAHL (1980–1989 and 2009), PsycINFO (1806–1809 and 2009), American College Physicians Journal Club (September 2009), Health Technology Assessment (September 2009), NHS Economic Evaluation Database (September 2009), Database of Halley Stewart Library (St Christopher’s Hospice) (September 2009), International Pharmaceutical Abstracts (1970–1979 and 2009), and Iowa Drug Information System (1966–1969 and 2009).

Search strategies for the 14 databases included variations of the following keywords: dyspnea, breathing, breathless, shortness of breath, breathing difficult, and breathing labour paired with benzodiazepine, anxiety agents, and a long list of specific benzodiazepine agents.

Randomized controlled trials and controlled clinical trials assessing the effect of benzodiazepines in relieving breathlessness in patients with advanced stages of cancer, chronic obstructive pulmonary disease (COPD), chronic heart failure (CHF), motor neuron disease (MND), and idiopathic pulmonary fibrosis (IPF) were included.

Studies using all drugs in the pharmacologic class called benzodiazepines at any dose, frequency, duration, and through any route for the relief of breathlessness compared with placebo or active control were included.

Studies were excluded if they

• Were not controlled or randomized trials
• Included participants with acute or chronic asthma, pneumonia, or other potentially curable diseases.

A total of 1,309 references were reviewed initially from the databases, which were narrowed to 31 articles for closer evaluation. The final evaluable seven studies included seven randomized controlled trials, five crossovers, and two parallel designs, four with COPD and three with cancer. All studies were initially assessed for quality using the Review Manager (RevMan) and secondarily evaluated using “The Edwards Method Score,” and articles were graded for inclusion in data analysis or the meta-analysis if high quality. Two studies used alprazolam, one study used diazepam, two studies used midazolam with morphine, one study used lorazepam, and one study used clorazepare.

• Of the 200 participants analyzed, 52 had COPD and 148 had cancer.
• All studies were small, ranging from 5-29 participants, except for two studies (Navigante, 2006 with 101 participants and Naviagante, unpublished with 63 participants).
• Three studies had power calculations, but only two reached adequate numbers for power.
• Three studies included patients with cancer.
• Most stuides used the VAS or NRS scale for assessing breathlessness.
• Most studies measured breathlessness at rest, and three studies measured breathlessness with exercise.
• Anxiety was measured in two studies, depression in two studies, walking tests in three studies, and benzodiazepine adverse effects or attrition in all studies.

Only six of the seven studies were included in meta-analysis, and the other was included in general data. Other measured outcomes of the studies included anxiety, depression, adverse effects of benzodiazepines, functional exercise capacity, quality of life, and study attrition. Overall, the analysis (four studies) and meta-analysis (three studies) with 52/47 participants showed no significant effect of three different benzodiazepines in relief of breathlessness in patients with advanced COPD. The three studies of patients with cancer included in analysis included two with morphine control and one with placebo control. One morphine-controlled study showed no significant effect of midazolam as compared to morphine, and one showed a slightly better improvement of breathlessness in patients receiving midazolam. Although overall no effect of benzodiazepines could be demonstrated, this meta-analysis should be interpreted with caution given the hetereogeneity and design differences of these studies. Pooling of placebo-controlled and morphine-controlled data showed no significant effect of benzodiazepines on breathlessness at rest. Four of seven studies measured anxiety with different scales, and none demonstrated anxiety alterations from baseline or as compared to a control group. Three studies examined depression and did not show differences between the intervention and placebo groups.

When considering all studies, no enhanced effectiveness for management of breathlessness was noted with use of benzodiazepines either at rest or with breakthrough dyspnea for patients with COPD or cancer. When excluded studies with lesser research strength of evidence were compared with stronger evidence, these conclusions were affirmed.

Although overall no effect of benzodiazepines could be demonstrated, this meta-analysis should be interpreted with caution given the hetereogeneity and design differences of these studies.

The authors recommend larger studies with more participants, inclusion of more patients with other known etiologies of breathlessness (e.g., CHF, MND), treatment of breakthrough dyspnea, and use of benzodiazepines in patients with breathlessness during panic attacks.