Can Prescription Drugs Lead to a DWI Charge in Texas?

 Posted on August 23, 2026 in Criminal Defense

Many people think of alcohol or illegal drugs when it comes to DWI charges, yet some medications can also affect a person's ability to drive safely. This can happen even when the medication was prescribed by a doctor.

In Texas, prescription drugs can lead to a DWI charge if they cause a driver to become intoxicated. If you were arrested for a drug-related DWI in 2026, a Llano County DWI defense attorney can help explain the charge and what may happen next.

Can You Get a DWI From Prescription Medication in Texas?

Texas Penal Code Section 49.04 makes it a crime to operate a motor vehicle in a public place while intoxicated, but Texas DWI law covers more than just alcohol.  Under Texas Penal Code Section 49.01, intoxication can mean losing the normal use of your mental or physical abilities because of a drug. The law also covers intoxication caused by a mix of drugs and alcohol.

This means a driver does not need a blood alcohol concentration of 0.08 percent to face a DWI charge. A prescription drug may lead to an arrest if police believe it affected the person's ability to drive. The type of medicine can also matter, since some are known to affect reaction time or judgment.

Does Having a Prescription Prevent a Texas DWI Charge?

Having a valid prescription does not prevent a DWI charge. The prescription gives you the legal right to possess and use the medication as directed. However, it does not give you the right to drive while intoxicated.

It's important to be aware that a person may take the correct dose and still feel side effects that make driving unsafe. The U.S. Food and Drug Administration warns that some medicines can affect driving for several hours.  This can be a surprise for drivers who took their medication as directed, and why drivers should read medication warnings before getting behind the wheel.

How Do Police Look for Prescription Drug Impairment in Texas?

Drug-related DWI cases can look different from alcohol cases. Alcohol has a legal limit of 0.08 percent, but Texas does not use a similar limit for prescription drugs in a standard DWI case.

Instead, police may look for signs that a driver has lost the normal use of their mental or physical abilities. Evidence may come from the traffic stop and events that happen after the stop.

Police may consider:

• How the person was driving before the traffic stop
• What the driver said about medication use
• How the driver performed on field sobriety tests
• The driver's behavior during the stop
• The results of a blood or urine test

One piece of evidence does not tell the whole story. The state still has to prove the elements of DWI beyond a reasonable doubt.

Does a Positive Drug Test in Texas Prove You Were Intoxicated?

A positive test can be important evidence, but finding a drug in someone's system does not always show how much it affected that person's driving. This is one reason prescription drug DWI cases can involve complex scientific evidence. Drug testing itself presents challenges, since some drugs remain in the body even after their strongest effects have passed.

Blood testing may show which substances were present in a driver's body. Other evidence can help show what was happening around the time of the traffic stop. The type of drug can also affect how test results are understood. For that reason, test results should be reviewed along with the other evidence in the case.

What Are the Penalties for a Prescription Drug DWI in Texas?

A prescription drug DWI carries the same basic penalties as a DWI involving alcohol. According to the Texas Department of Transportation, a first DWI offense can result in up to 180 days in jail. It can also bring a fine of up to $2,000 and a driver's license suspension of up to one year.

Penalties become more serious if you have another DWI conviction, and other issues can also increase the possible punishment. For example, Texas has a separate offense for driving while intoxicated with a passenger younger than 15.

A DWI can have effects beyond the criminal case, including impacts on employment or basic needs. This is why understanding the charge and the evidence behind it is important.

Contact a Llano County, TX Prescription Drug DWI Defense Lawyer Today

A prescription drug DWI can involve medical records and test results that play an important role in the case. Attorney Russ Alan Baker has more than 15 years of legal experience and holds a Bachelor of Science degree in Biology. His background in biology helps him handle criminal cases that involve scientific evidence, including DWI cases.

If you've been charged with a DWI, contact a Llano, TX DWI defense attorney at the Law Office of Russ Alan Baker, PLLC or call 325-216-2006 to discuss your case and next steps.