Imagine being an asthma patient for a second.
You are driving along at night while you are really tired. You may swerve a bit and your reaction time is slow. Suddenly you see blue and red lights flashing in your rear-view mirror. You get nervous and start breathing fast. Since you are an asthma patient you reach for your inhaler and take a couple puffs as per your normal habit. The cop asks you to step out of the vehicle and take a portable breath test (PBT) and you oblige because you know you had nothing to drink.
To your utter surprise, you register a BAC over .08 and the cop arrest you for DUI.
Many popular inhalers for asthmatics have alcohol bases and the residual spray in your mouth and your lungs cause the highly inaccurate PBT device to record a high BAC level.
You may think that this is rare, but in my time as a PA DUI Attorney, I have seen numerous cases along these lines. There are many medicines and medical conditions that produce symptoms that may be misinterpreted as being DUI. This why anyone who faces medical conditions like diabetes and acid reflux as well as anyone taking medication should contact an experienced DUI attorney if they are charged with a DUI violation.