Most people associate driving under the influence with being impaired by alcohol. However, you can also be convicted of a DUI and face penalties based on being under the influence of drugs, including prescription medication. Some states have per se drug DUI rules, such that you cannot drive if you have a certain concentration of controlled substances in your system. Even if you have less than the legal limit of a substance in your system, you can still get a DUI if the arresting officer believes you to be impaired by alcohol or other substances.
What Does Impairment Mean?
In most cases, prescription medication DUIs are based on impairment rather than the concentration of a prescription drug in your system. Impairment is defined and proven differently under different state laws. For example, under California Vehicle Code section 23152(f), you are considered to be driving under the influence of drugs if your mental or physical capacities are impaired so much that you do not have the ability to drive with the care that sober people of ordinary prudence would exercise under similar circumstances. When prescription drugs substantially influence a driver's ability to safely operate a vehicle, it is possible that the driver could be arrested and face charges for a prescription drug DUI.
Evidence of Impairment
Most prescription medication DUI cases are not based on drug tests, but instead on other evidence of impairment. State laws vary, but generally the prosecution must prove that the driver was unable to safely operate the vehicle due to the prescription drug usage by presenting evidence such as the arrest report and the officer’s testimony.
Each state imposes its own penalties for a prescription medication DUI, and these penalties may vary depending on whether it is a first offense or a subsequent offense. In Illinois, for example, most first-time DUIs are charged as misdemeanors unless there are aggravating factors that could elevate the charges to a felony.
There are defenses that may be available for prescription medication DUIs. As with other types of DUIs, you may be able to challenge a prescription medication DUI by arguing that the arresting officer did not follow proper procedures in initiating or conducting your stop. Under the Fourth Amendment, the police must have a reasonable suspicion of a crime to pull you over, and even then, they can only conduct a limited investigation as part of the stop. A reasonable suspicion could be based on a driver making an illegal turn, weaving, excessively speeding, driving much too slowly, drifting, or stopping in the road without a reason.
If there was no reasonable suspicion to pull you over, it may be possible to get evidence from the stop that showed impairment suppressed. Similarly, you may have a strong procedural defense if there was no "probable cause" to arrest you for the prescription medication DUI or if an attorney can suppress the results of the field sobriety tests or other methods used to establish probable cause.
Some states allow a driver to present their valid medication prescription as a limited defense to a DUI charge related to that prescription.
If you are charged with being impaired while driving under the influence of prescription medications, you will need to consult an attorney or review state laws regarding whether it is possible to raise a limited defense for driving on prescription medications in your state. In most states that allow such a defense, you would need to show that you had a valid prescription and you took the medication just as it was prescribed to you. The type of drug at issue and your doctor's instructions would be critical to whether this defense would be appropriate. For example, if you were taking a prescription drug in order to sleep, and then you consciously got into your car to drive to the grocery store to pick something up instead of going to bed, you probably would not be able to prevail in your case by using this limited defense.
Often, there are warning labels on prescription drugs letting consumers know that certain drugs could cause impaired driving. With newer prescription drugs, you could potentially raise this defense if the manufacturer did not know that impaired driving could be a side effect of the medication, or if there was a failure to warn.