Drug treatments to ease breathlessness in cystic fibrosis

Review question

What is the evidence that drug treatments for breathlessness (also known as dyspnoea) in people with cystic fibrosis are effective and safe?

Background

Cystic fibrosis is a life-limiting genetic disease. As the disease progresses, thick sticky mucus is formed in the lungs, pancreas and other organs. This thick mucus increases risk of infection, blocks the airways and causes severe breathlessness. Easing of this breathlessness is an important goal for care of people with cystic fibrosis. Many methods have been suggested to address this problem and many drugs have been reported to ease breathlessness. The drugs can be administered through various routes - they might be inhaled, swallowed, injected under the skin, into muscle or into a vein or be absorbed through the skin (either on the body or through membranes inside the mouth or nose). Despite so many drugs being available, there are no defined guidelines for drug treatments aimed at easing breathlessness in people with cystic fibrosis.

Search date

The evidence from the Cochrane Cystic Fibrosis Trials Register is current to: 24 July 2017; the searches of ongoing trial registries are current to 31 July 2017.

Study characteristics

We had planned to include studies comparing different treatments to ease breathlessness in people with cystic fibrosis where the participants were put into the different treatment groups at random. Our search found only one study in which seven people first received either a drug called hydrocodone or a placebo (dummy treatment) and then swapped to the other treatment; but this study did not report results separately for each treatment arm, so we are not able to include it in the review.

Key results

No studies fulfilled the inclusion criteria, therefore it is not possible to comment on the outcomes we wished to report on in this review. Until evidence becomes available, the review authors feel that it is advisable for doctors to follow any local or national guidelines. The authors recommend research in this area should take ethical considerations into account and should focus on the safety of the drugs, improvement in quality of life, breathlessness scores and length of hospital stay.

Authors' conclusions: 

Due to the lack of available evidence, this review cannot provide any information for clinical practice. The authors call for specific research in this area after taking into account relevant ethical considerations. The research should focus on the efficacy and safety of the drugs with efficacy being measured in terms of improvement in quality of life, dyspnoea scores and hospital stay.

Read the full abstract...
Background: 

Cystic fibrosis is a life-limiting autosomal recessive genetic illness. A feeling of shortness of breath is common in cystic fibrosis, especially as the disease progresses. Reversing the underlying cause is the priority when treating breathlessness (dyspnoea), but when it is not feasible, palliation (easing) becomes the primary goal to improve an individual's quality of life. A range of drugs administered by various routes have been used, but no definite guidelines are available. A systematic review is needed to evaluate such treatments.

Objectives: 

To assess the efficacy and safety of drugs used to ease breathlessness in people with cystic fibrosis.

Search strategy: 

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books.

Date of last search: 24 July 2017.

We searched databases (clinicaltrials.gov, the ISRCTN registry, the Clinical Trials Registry India and WHO ICTRP) for ongoing trials. These searches were last run on 31 July 2017.

Selection criteria: 

We planned to include randomised and quasi-randomised controlled trials in people with cystic fibrosis (diagnosed by a positive sweat chloride test or genetic testing) who have breathlessness. We considered studies comparing any drugs used for easing breathlessness to another drug administered by any route (inhaled (nebulised), intravenous, oral, subcutaneous, transmucosal (including buccal, sublingual and intra-nasal) and transdermal).

Data collection and analysis: 

The authors assessed the search results according to the pre-defined inclusion criteria.

Main results: 

The search yielded only one study (cross-over in design), which did not fulfil the inclusion criteria as no data were available from the first treatment period alone.

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