Many drivers are surprised to learn they can be charged with DWI (Driving While Impaired) in North Carolina even when they’ve taken medication legally prescribed by a doctor. Unlike alcohol-based DWIs, prescription drug cases are harder to measure and often depend on officer observation and lab results — not a breath test.
If you’ve been charged with a prescription medication DWI, it’s critical to understand how the law defines impairment, what evidence the State must prove, and which defenses may help protect your record and license.
Prescription Drug DWIs Are Still DWIs
Under N.C. Gen. Stat. § 20-138.1, you can be convicted of DWI if you:
- Drive while under the influence of an impairing substance,
- Have any amount of a Schedule I controlled substance in your system, or
- Have a BAC of 0.08 or higher.
Importantly, “impairing substances” include prescription medications and lawful drugs if they impair your mental or physical abilities to drive safely.
That means even if you’re taking your medication as prescribed, you can still face a DWI if it affects your coordination, reaction time, or judgment.
Common Prescription Drugs That Lead to DWI Charges
Law enforcement officers are trained to look for signs of impairment from certain drug classes that can affect driving ability. Common culprits include:
- Benzodiazepines (e.g., Xanax, Valium, Ativan) – prescribed for anxiety or sleep, but can cause drowsiness or slowed reflexes.
- Opioid painkillers (e.g., OxyContin, Vicodin, Percocet) – can dull alertness and impair reaction time.
- Muscle relaxants (e.g., Soma, Flexeril) – cause fatigue and reduced coordination.
- Antihistamines (e.g., Benadryl) – can induce drowsiness even at recommended doses.
- Antidepressants and mood stabilizers – may affect balance or focus, especially when combined with alcohol or other meds.
Sometimes, drivers are accused of being “under the influence” when they are merely showing side effects of legitimate treatment — which is why these cases require careful medical and legal review.
How Police and Prosecutors Prove Drug Impairment
Unlike alcohol-related DWIs, there is no per se limit for prescription drugs. Instead, prosecutors must prove impairment, meaning your ability to drive was appreciably diminished.
Evidence may include:
- Officer observations: erratic driving, slurred speech, or unsteady balance.
- Field sobriety tests: though these are designed for alcohol, they’re still used in drug cases.
- Drug recognition experts (DREs): officers trained to evaluate physical signs of drug use.
- Blood or urine tests: showing presence of prescription medications.
- Statements or admissions: such as telling police what meds you took.
However, presence doesn’t equal impairment — and that’s where many of these cases fall apart.
Therapeutic Use vs. Impairment
The key question in a prescription DWI case is not whether you took medication, but whether it impaired your ability to drive safely.
North Carolina courts recognize that some drugs remain in your system long after their effects wear off. Having a trace amount in your blood doesn’t automatically prove impairment.
For example:
- A driver who took hydrocodone the day before might still test positive even if no longer impaired.
- Someone prescribed anxiety medication may appear nervous or fatigued — symptoms mistaken for intoxication.
An experienced attorney can use toxicology experts to explain therapeutic levels and distinguish lawful use from actual impairment.
Mixed Substances: The Hidden Risk
One of the most common — and dangerous — scenarios involves mixing prescription meds with alcohol or other drugs. Even small amounts can interact unpredictably, multiplying the effects of each substance.
Prosecutors often use this combination to strengthen impairment claims. But defense attorneys can challenge whether the interaction truly caused unsafe driving or whether other medical factors were at play.
Penalties for Prescription DWI in North Carolina
A DWI conviction for prescription medication carries the same penalties as an alcohol-related DWI. Depending on the circumstances, you could face:
- License suspension (typically one year for a first offense).
- Fines and court costs up to several thousand dollars.
- Possible jail time, probation, or community service.
- Mandatory substance abuse assessment and treatment.
- Ignition interlock requirements, even without alcohol involvement.
A conviction also creates a permanent criminal record, which can impact professional licensing and employment.
Common Defenses in Prescription Medication DWI Cases
Defending against a prescription-related DWI requires analyzing both the science and the procedure of your case. Common defenses include:
- No Evidence of Actual Impairment
If your driving was safe and cooperative, and no field tests show significant impairment, prosecutors may struggle to prove guilt beyond a reasonable doubt. - Therapeutic Use at Prescribed Levels
Expert testimony can show that drug levels in your system were within normal therapeutic ranges — not enough to cause impairment. - Unreliable Field Sobriety Tests
These tests were designed for alcohol, not medication. Fatigue, medical conditions, or age can cause false failures. - Invalid or Contaminated Blood Test
If the blood draw was mishandled or not analyzed properly, results may be unreliable and inadmissible. - Lack of Probable Cause for the Stop
If police stopped your vehicle without lawful justification, any evidence gathered afterward (including drug tests) can be suppressed. - Improper DRE Evaluation
Drug recognition experts must follow strict protocols. Any deviation — such as skipping medical clearance — can invalidate their opinion.
Medical Documentation Can Be Crucial
If you were prescribed the medication, gather documentation immediately:
- Prescription records.
- Doctor’s notes on dosage and usage.
- Pharmacy receipts or refill logs.
- Evidence that you followed medical advice.
This helps demonstrate you weren’t abusing the medication or acting irresponsibly.
Your attorney may also consult with medical experts to interpret drug concentration levels and explain how the medication affects people differently.
Why Legal Representation Matters
Prescription drug DWI cases are scientifically complex. They require not just a defense lawyer — but one familiar with both North Carolina DWI law and toxicology evidence.
A knowledgeable DWI defense attorney can:
- Analyze the chemical test results for errors.
- Challenge officer training and DRE conclusions.
- Present expert testimony on therapeutic use.
- Negotiate for reduced charges or dismissal if impairment isn’t proven.
Key Takeaway
In North Carolina, a valid prescription isn’t a defense if the medication impairs your driving — but neither is its presence in your system automatic proof of guilt. Prosecutors must show actual impairment, not just lawful use.
If you’ve been charged with a DWI involving prescription drugs, you need an attorney who understands both the medical and legal aspects of your case. The DWI defense team at Martine Law can help you challenge weak evidence, protect your license, and safeguard your record.
Contact us today for a confidential consultation about your case.