Clinical pharmacology of melatonin in the treatment of tinnitus: a review

We performed a review with the purpose to summarise, analyse and discuss the evidence provided by clinical studies evaluating effectiveness of melatonin in the cure of tinnitus. Due to the fact that there is no satisfactory treatment for tinnitus, clinical research has explored new therapeutic approaches. A search of Pubmed, Medline, Embase, Central and Google Scholar was conducted to find trials published prior March 2014 on melatonin in the treatment of tinnitus. Design of the studies, randomization, allocation concealment procedures and diagnostic instruments (scales for tinnitus evaluation) were critical evaluated. Five clinical studies have been included. Three of them tested effectiveness of melatonin alone, the remaining two along with sulpiride and sulodexide respectively. Considered clinical trials adopted various experimental designs: single arm, randomised placebo-controlled and randomised placebo-controlled followed by crossover. These studies were characterised by several methodological weaknesses. Confirmation of melatonin clinical effectiveness in the treatment of tinnitus cannot be given in the light of the biases observed in the considered evidence. Melatonin seems to improve sleep disturbance linked to tinnitus.