Legal Medication, Real Charges: Texas Prescription DWIs

 Posted on October 30, 2025 in DWI

Many Texans are dismayed to learn that they could face DWI charges, even when taking legally prescribed medication. Texas Penal Code section 49.02 does not just refer to alcohol when talking about "intoxication." Intoxication can mean impairment by alcohol, illicit drugs, prescription drugs, or even over-the-counter drugs that affect mental or physical faculties.

Medications for anxiety, pain, or even sleep can be legally in your system and still lead to an arrest if they are believed to have caused your impairment. You must understand how prescription drug DWIs are prosecuted in Texas, and what defenses exist that can make a difference in your future and your freedom. An experienced Parker County, TX DWI lawyer can help you make informed choices now that will yield the best possible outcome.

Understanding What Can Lead to a Texas Prescription Drug DWI

The most important thing to know is that possessing a valid prescription for a medication is not a defense if impairment can be proven. The loss of normal mental or physical faculties can be due to alcohol, a controlled substance, a legal drug, an over-the-counter drug, or a combination. Some of the most common prescription drugs involved in DWI arrests in Texas include:

• Benzodiazepines such as Xanax, Valium, Klonopin, and Ativan are anti-anxiety medications that can cause drowsiness, dizziness, and impaired coordination.
• Sleep aids like Lunesta and Ambien are sedative-hypnotics, which can cause drowsiness that lingers into the next day and, in some cases, can cause "sleep driving."
• Painkillers like hydrocodone, Percocet, and oxycodone are opioid pain relievers that can cause confusion, dizziness, and drowsiness.
• Muscle relaxants like Soma and Flexeril can cause blurry vision, drowsiness, and extreme fatigue.
• Certain antidepressants can cause confusion, dizziness, and drowsiness that mimics alcohol intoxication during a field sobriety test.
• ADHD medications like Adderall are stimulants that can lead to impaired judgment, anxiety, and dizziness.
• Even some prescription and over-the-counter allergy medications and cold remedies can cause drowsiness and slow reaction times.

How Is Prescription Drug Impairment Proven in Texas?

There is no breath test equivalent that officers can use to prove impairment resulting from drugs definitively. While a blood draw can detect medications, the mere presence of a drug may not correlate with actual impairment. Texas law focuses more on whether a drug impaired "normal" faculties instead of whether it was legally obtained when attempting to prove impairment.

Virtually any drug that has a warning on it advising against "operating heavy machinery" explicitly includes driving a vehicle. "Poly-drug" confusion is a state of mental confusion resulting from using multiple drugs at the same time, even when those drugs are as harmless-seeming as caffeine, allergy medications, and sleep medications.  

With no BAC reading, police officers rely on their initial observations of erratic or unsafe driving behavior, followed by an in-person assessment during a traffic stop. Weaving, drifting, driving too slow or too fast, and ignoring traffic signals can all lead to an initial stop. The officer will then look for physical signs of impairment like poor coordination, slurred speech, dilated pupils, and unsteadiness, as well as behavioral cues like confusion, drowsiness, or difficulty with basic tasks.

Field sobriety tests may confirm an officer’s suspicion of impairment, but while these tests are validated for alcohol detection, they are scientifically proven to detect drug-related impairment reliably. A Drug Recognition Expert (DRE) may be called in for a 12-step evaluation; however, the reliability of these evaluations has also been debated.

Since a key aspect of a DWI case involves proving actual impairment, a highly skilled DWI attorney can challenge many of these interpretations of impairment. Since a drug DWI has the same penalties as an alcohol DWI, it is imperative to challenge the lack of impairment evidence, improper blood draw, faulty DRE procedures, or officer bias.

Contact a Weatherford, TX DWI Lawyer

If you were arrested for DWI after taking a prescription drug, you should know that these cases often hinge on technical details. Consulting with a highly skilled Parker County, TX impaired driving attorney from Soraya Joslin, P.C. can help protect your job, your license, and your future. Attorney Joslin has nearly 30 years of experience, and her time serving as an ADA has provided her with a deeper understanding of how the criminal justice system operates from both sides. To schedule your free consultation, call 817-599-7005.