A buddy of mine tried the excuse of a coughing fit after he rolled his Chevy. Blood alcohol was up and the ins co said NO. He had coughed profusely in front of the investigating officer and kept swigging from a cough medicine bottle. All documented. He WON! But it cost him $3k... >;-) Contents of the cough medicine bottle were not analysed.

YMMV and so may the sale of your justice system.