Randomization
Sequence generation . Participants were randomly assigned (1:1) to receive betahistine or a matching placebo. The sequence was generated by block randomization of six, and the allocation codified by aleatory numbers, using the software SAS (version 9.1).
Allocation concealment . Allocation concealment was performed using sequentially numbered, opaque and sealed envelopes, which were identified only by the randomization number.
Implementation . Eurofarma S.A. collaborators provided the allocation sequence, the active drug and placebo, and the allocation envelopes (eFigure 1 in Supplement). The principal investigator enrolled participants and the study clinical center (UPECLIN) pharmacy managed the intervention assignment and delivery.