Randomization and blinding
Randomization was performed by impartial person using electronic random number generator. (Assignment ratio was 1:1, blocks of two). Blinding of the assignment was achieved by using serially numbered, solid, and stapled wrappers. Placebo tablets were manufactured in Zeta Pharma Company, and they were indistinguishable from pentoxifylline tablets in their appearance. The assignment was concealed from the participant, the doctor who referred the patient, the healthcare provider, the statistician, and the evaluator.