Smart & Aggressive
attorneys defending you.
click for a free consultation

Can Pre-Existing Medical Conditions Play a Role in a DUI Case?

Posted on August 8, 2023 in DUI

When law enforcement in Arizona stops a driver for allegedly driving under the influence (DUI), they will conduct tests to determine if the driver is impaired by drugs or alcohol. However, many medical conditions and legal medications can present symptoms that are similar to drunkenness, resulting in a DUI arrest. In this situation, the individual may be able to argue against the DUI charge using medical evidence.

Medical Conditions That Can Impact a DUI Investigation

A law enforcement officer cannot legally arrest someone for a DUI without probable cause. This means reasonable grounds to make an arrest for violating Arizona’s driving under the influence law (ARS 12-1381). During a traffic stop, an officer will look for possible signs of driver intoxication. This may include slurred speech, bloodshot eyes, confused or inappropriate behaviors, trouble balancing or walking, and a lack of coordination. 

However, many pre-existing medical conditions can mimic the effects of intoxication, including:

  • Diabetes
  • Heart attack
  • High blood pressure
  • Infections
  • Loss of vision or hearing
  • Low blood sugar
  • Migraine
  • Panic attack
  • Post-traumatic stress disorder
  • Ruptured aneurysm
  • Stroke

In addition, prescription or over-the-counter medications can cause side effects that mimic the effects of alcohol, such as drowsiness and confusion. These medical conditions or medications can alter a police officer’s analysis of a potential DUI case, resulting in the arrest of the driver with or without blood alcohol content (BAC) evidence, if the officer cannot tell the difference between a DUI and the medical condition.

Medical Conditions and Field Sobriety Tests

Two main types of tests are used to ascertain whether a driver is under the influence of intoxicating drugs or liquor: BAC tests and field sobriety tests. BAC tests – including breath, blood and urine tests – are not optional for drivers in Arizona. Drivers give their implied consent to these BAC tests when they obtain their licenses. Refusing a breathalyzer or another BAC test will automatically result in the driver’s license being suspended for one year, even without a DUI conviction.

However, drivers are not legally required to participate in field sobriety tests, where law enforcement officers ask a driver to engage in certain physical tests. Examples are the one-legged stand test and horizontal gaze nystagmus test. These tests are notoriously inaccurate and subjective. Medical conditions and medications can change the results of a field sobriety test. For example, a driver with a pre-existing knee injury may not be able to stand on one leg. Failing these tests due to a medical condition could result in a DUI arrest.

What if There Was Alcohol in Your System?

In some cases, a driver does have alcohol in his or her system, but a pre-existing medical condition contributed to the impression of intoxication during a traffic stop, resulting in a DUI charge. In this scenario, convincing a judge or jury that alcohol is not responsible for the symptoms that a police officer noted during your traffic stop can be difficult.

You may need to hire an experienced DUI defense attorney to help you defend against a DUI allegation in this situation. Your attorney can use evidence such as medical documents and medical experts to prove that your health condition presented DUI-like symptoms and that this is what led to your arrest – not intoxication. 

If you have recently been arrested for a DUI and you have a medical condition, the best way to protect your rights is by contacting a DUI attorney at Rosenstein Law Group. Request a free case consultation today.

Contact Us


  • All fields required *
  • This field is for validation purposes and should be left unchanged.
  • This field is for validation purposes and should be left unchanged.