Metered dose inhalers can give a false-positive breathalyzer result.
There are some cases of this actually happening.
Some of the newer HFA inhalers contain small amounts of ethanol as a co-solvent. After inhaling the medication, this ethanol becomes aerosolized in the lungs...which can be picked up by a breathalyzer.
Even inhalers that do not contain ethanol as a vehicle can trigger a false reading. The chlorofluorocarbon (CFC) propellants used are chemically similar to ethanol and have been known to interfere with breathalyzer readings.