No doubt, if you're taking sleeping pills and you are flight crew, you should have cleared the medication with either your AME or the CAA Medical Section at LGW. If you haven't done either of those things and you're operating as flight crew then you are compromising your flight colleagues and yourself.
As for Trazodone, two of the possible side effects are increased heart rate and self hurt thoughts while another two are painful, prolonged penis erection and blurred vision. One suspects that at least one CAA somewhere might view the drug with a quizzical or even jaundiced look of disapproval?