Can the medications you take cause false breath test readings?

Law enforcement agencies commonly use breath test readings to determine a person’s blood alcohol concentration when investigating cases of suspected drunk driving. However, certain medications can lead to false readings.

Understanding why this happens is important, as it can affect individuals’ legal rights and overall well-being.

The mechanism

Medications, when ingested, can sometimes interact with the body’s chemistry in ways that mimic the presence of alcohol. This can result in a false positive on a breath test, even when a person has not consumed any alcoholic beverages.

Medications that interfere

Some mouthwashes and breath fresheners contain alcohol as an ingredient. When used shortly before a breath test, they can produce misleading results. These products introduce alcohol into the oral cavity, creating a temporary spike in BAC readings.

Also, certain over-the-counter and prescription medications contain alcohol as an active ingredient. Cough syrups, liquid antibiotics and some pain relievers fall into this category. When people consume them in significant quantities, the medications can lead to elevated BAC levels. About 66% of U.S. adults take prescription drugs, and usage is even higher among seniors and people with chronic issues.

Ketoconazole and metronidazole

Ketoconazole and metronidazole, used to treat fungal and bacterial infections, can interfere with alcohol metabolism. They inhibit the enzyme responsible for breaking down alcohol, leading to an accumulation of acetaldehyde, which a breath test may detect.

Diabetes medications

Some medications that manage diabetes may lead to false positives. They can alter the way the body processes alcohol, potentially resulting in elevated BAC readings.

Asthma inhalers

Inhalers containing ethanol as a propellant may introduce alcohol into the respiratory system. Taking a breath test shortly after using such an inhaler may yield inaccurate results.

Unfortunately, false breath test readings can have serious consequences, including damage to one’s reputation. Alternative testing methods, such as a blood test or urine test, may be more accurate.