You can be arrested for DUI in Illinois even if you were taking a legally prescribed medication. Having a valid prescription does not automatically protect you from a DUI charge. What matters under Illinois law is whether the substance impaired your ability to drive safely, not whether you had legal permission to take it. If you are facing a DUI charge related to prescription medication in 2026, our experienced Chicago, IL DUI defense lawyer will explain the potential defenses that apply to your case.
What Does Illinois Law Say About Prescription Drug DUIs?
Under 625 ILCS 5/11-501, it is illegal to drive or be in actual physical control of a vehicle while under the influence of any drug or combination of drugs that makes you incapable of driving safely. In Illinois, you do not necessarily have to be driving. Being in actual physical control of a vehicle can include situations where you are sitting in the driver’s seat with the ability to operate the vehicle. This means that if a police officer believes you were impaired by a medication you were taking, you can be arrested and charged with DUI even if you took the medication exactly as prescribed.