You took medication your doctor prescribed. You weren’t drinking. Then you saw red and blue lights in the mirror, answered a few questions on the side of the road, and suddenly an officer said you looked impaired.
That moment leaves people stunned. We hear the same question across the desk: “How can this be a DWI if my medication was legal?”
Texas DWI law doesn’t focus only on alcohol. The legal definition of intoxication includes losing the normal use of mental or physical faculties because of alcohol, a controlled substance, a drug, a dangerous drug, a combination of substances, or another substance.[1] A lawful prescription does not end the inquiry.
But neither does a prescription bottle, a blood result, or an officer’s first impression settle the case.
A DWI charge is an accusation. The State still has to prove its allegation with evidence. In a prescription-medication case, the hard question usually is not whether medication was present. The real question is whether the State can show that medication caused a loss of normal faculties while the person was driving.
A representative situation: lawful medication, an alarming arrest
Consider someone who takes a prescribed pain medication after a difficult week at work. They leave a grocery store tired, dealing with back pain, and worried about a parent in the hospital. An officer stops them after a wide turn at an intersection.
The driver speaks slowly. They’re nervous. They have an old knee injury that makes balancing difficult and tell the officer about the prescription because they think honesty will clear things up.
Instead, the conversation becomes part of a DWI investigation.
In a situation like this, the medication may be legal, but the details still matter. What did the officer actually see? What was the driving behavior? When was the medication taken? What dose was prescribed? What else could explain the observations? Did the blood result show only that a substance was present, or does the evidence actually connect that substance to the claimed impairment?
Those questions are not technical footnotes. They are the case.
A valid prescription does not give the State a shortcut
Police and prosecutors may look at the prescription, the driver’s statements, video footage, medical information, and any chemical testing. They may also point to things they believe show impairment, such as driving behavior, speech, balance, or coordination.
We do not brush those facts aside. We examine them closely.
A medication appearing in a blood test does not answer every question by itself. Many people take lawful medication exactly as directed. A careful defense review looks beyond a label or lab result and asks whether the evidence really shows a loss of normal faculties caused by that medication at the relevant time.
That is a very different question from, “Was a drug found in the person’s system?”
Texas appellate decisions show why the facts need careful attention. In Farmer v. State, the Court of Criminal Appeals considered a DWI case involving prescription medications, including Ambien, Ultram, and Soma. The opinions discuss the unusual and fact-specific issues that can arise when medication, knowledge of possible effects, and claimed impairment intersect.[2] No one should read that decision as a simple defense rule. It does show that prescription-medication cases can carry details a generic alcohol DWI case may not.
The story behind the officer’s observations matters
An officer may write that a driver had slow speech, appeared unsteady, seemed confused, or performed poorly on roadside tests. Those details can matter. They also need context.
Pain can affect movement. Anxiety can change the way someone answers questions. Fatigue can make a person look worn down. An old injury can affect balance. A medical condition may explain behavior that an officer reads as impairment. The timing of medication use, the directions on the label, and the person’s own baseline can all matter too.
We have seen how quickly a report can turn a human moment into a one-sided story. The person in the report becomes “the driver.” The reasons behind how they moved, spoke, or reacted get left out.
That is why we want to see the video, the records, the testing information, and the full timeline. A written report is a starting point, not the final word.
Do not make the case harder in the first few days
After an arrest, people often want to explain themselves to everyone. They call the officer. They text friends who were with them. They search online for a quick answer and start sorting through their phone or medical records on their own.
Slow down.
Don’t delete messages, change records, or try to make your history look cleaner than it looks. Don’t assume one conversation can fix the problem. Preserve the paperwork you received. Keep the medication container and its directions if you still have them. Write down a straightforward timeline while your memory is fresh, including when you took medication, what you ate or drank, where you were going, and what happened during the stop.
Then talk with a defense lawyer who can review the situation as a whole.
What we look for in a prescription-medication DWI case
We look at the same question from more than one angle. Was the stop lawful? What do the body-camera and dash-camera recordings show? Did the officer’s description match the video? What did testing reveal, and what does it fail to reveal? Are the reported symptoms consistent with the State’s theory, or could the evidence support another explanation?
We also look at timing. A medication record can show that someone had access to a drug. It does not automatically explain how that person was functioning at a specific moment behind the wheel.
Lewis & Ashworth PLLC brings former-prosecutor experience to that review. We know how the State may try to build an impairment narrative from a series of observations. We also know that a narrative is only as strong as the evidence underneath it.
You deserve a real review, not a guess
A prescription-medication DWI can feel especially unfair because the medication may have been lawful and medically necessary. That does not mean the case has no risks. It does mean the evidence deserves a serious, individualized review.
If you were arrested in Plano, Dallas, Collin County, or elsewhere in North Texas after taking prescription or over-the-counter medication, contact Lewis & Ashworth. Bring the paperwork you have, the medication information, and your questions. We will talk plainly about what happened, what evidence matters, and what needs attention now.
Legal references
[1] Texas Penal Code Section 49.01, definition of “intoxicated”. Confirm current statutory text against the Texas Legislature before publishing.
[2] Farmer v. State, No. PD-1620-12 (Tex. Crim. App. Oct. 9, 2013). The case includes separate opinions and fact-specific procedural issues; it should not be treated as a universal rule.