Study design (if review, criteria of inclusion for studies)
Published or unpublished randomised controlled trials (RCTs) or quasi-randomised controlled trials of sodium channel blockers compared to placebo or another sodium channel blocker or the same sodium channel blocker at a different dosing regimen.
List of included studies (5)
Bowler 1995; Donaldson 2006; Graham 1993; Knowles 1991; Pons 2000
Participants
Participants with a diagnosis of CF, based on a positive sweat test, or the presence of two disease-causing mutations on molecular genetic analysis.
Interventions
Amiloride; HS with amiloride pre-treatment
Outcome measures
Difference in relative change in FVC at six months; FEV1 (percent predicted); FVC (percent predicted); Mean difference in FEF25-75; Mean difference in FEV1; Mean difference in FVC; Mucus clearance (24 hour); Relative change in FEV1 from baseline; Relative change in FVC from baseline; Time to peak FVC
Main results
Five RCTs, with a total of 226 participants, examining the topical administration of the short-acting sodium channel blocker, amiloride, compared to placebo were identified as eligible for inclusion in the review. In three studies over six months, there was a significant difference found in the difference in relative change in FVC in favour of placebo (weighted mean difference -1.51% (95% confidence interval -2.77 to -0.25), although heterogeneity was evident. A two-week study demonstrated that hypertonic saline with amiloride pre-treatment did not result in a significant improvement in respiratory function or mucus clearance, in contrast to pre-treatment with placebo. There were no significant differences identified in other clinically relevant outcomes.
Authors' conclusions
We found no evidence that the topical administration of a short-acting sodium channel blocker improves respiratory condition in people with cystic fibrosis and some limited evidence of deterioration in lung function.