Poser 1992.

Methods	Double blind, randomised controlled trial
Participants	80 patients randomly assigned to 2 different treatment groups. Age and gender data were unavailable.
Interventions	Group 1: monotherapy with low‐molecular weight dextran and placebo Group 2: monotherapy with low‐molecular weight dextran and naftidrofuryl
Outcomes	Outcome assessment was done by direct comparison of thresholds between groups In this study there was a 70% improvement in the low frequencies in the dextran and naftidrofuryl group, compared to 40% in the dextran monotherapy group. The differences in the higher frequencies were not clear.
Notes	One patient in the dextran monotherapy group was excluded from the study as he had a allergic reaction on day 4 of the treatment
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Low risk

ATP = adenosine triphosphate 
 HAES = hydroxyethyl starch 
 LMW = low‐molecular weight 
 PGE1 = prostaglandin E1 
 PTA = pure tone audiometry