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Effects of Bronchial Inhalers on Breathalyzers

Authorities generally measure a person's blood alcohol level with a device known as a breathalyzer. After a suspect breathes into the machine, the amount of alcohol in the breath is calculated and then extrapolated to indirectly measure the BAC (blood alcohol concentration). If the BAC is high enough, then a person may be charged with a crime, especially if they were operating a vehicle at the time of offense. However, there are some substances that can alter a breathalyzer's results. Asthmatic medications such as albuterol are referred to as interferents because of their ability to distort a breathalyzer's validity.

  1. Breathalyzer Function

    • Most current breathalyzers use a technology known as infrared spectroscopy. This system allows for the identification of molecules based upon the way in which they absorb infrared light. In a normal state, molecules of a compound are always vibrating and when they absorb infrared light the vibration changes (via stretching or bending). Different types of bonds will absorb infrared light at different wavelengths. Alcohol can be identified if infrared light is absorbed in a specific wavelength. Subsequently the amount of infrared light absorption describes the amount of alcohol present.

    Asthma Inhalers and Breathalyzers

    • The breathalyzer measures the presence and amount of methyl groups, which are the primary chemical bonds found in alcohol. This poses problems because there are many other substances that also contain a methyl group. As a result the validity of a breathalyzer's result can be called into question. Albuterol, which is an asthmatic medication, very commonly cause a false-positive result because it contains methyl groups. When albuterol is inhaled, some amounts may still remain in the mouth and as a result will distort a breathalyzer result.

    Time Span of Effect

    • Since bronchial inhalers can erroneously affect a breathalyzer's result, field officers usually wait for a short amount of time before repeating the test. In some cases, the suspect is taken to a medical facility so a direct blood sample can be obtained for confirmation. A key issue that remains is the length of time that albuterol can falsely raise the BAC. A study completed by the Proceedings of the Western Pharmacology Society illustrated that in non-drinking subjects, a single inhaled sample from an inhaler could raise the BAC to 0.120 within the span of 30 minutes. However, the subjects returned to their baseline level within 6 minutes. The study then concluded that the subjects should be given a 20-minute break period prior to checking the BAC level.

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