Most people picture a drunk driver when they hear the word DUI. But in Delaware, having a valid prescription does not automatically protect you from a driving under the influence charge. If a prescription medication impairs your ability to drive safely, you can still face prosecution under Delaware’s impairment-based DUI law.

This is not a fringe scenario. Delaware law enforcement agencies investigate suspected drug-impaired driving, including cases involving legally prescribed medications. Delaware also maintains a statewide Drug Recognition Expert program to assist with suspected drug-impaired driving investigations. Understanding how this law works could protect your driving privileges, your record, and your livelihood.

What Delaware Law Says About Drug-Impaired Driving

Delaware’s DUI statute prohibits driving while under the influence of any drug, including lawfully prescribed medications. Although lawful prescription use can provide a defense to certain drug-content charges under Delaware law, it does not prevent prosecution for driving while actually impaired by a drug.

Delaware Code Title 21, Section 4177 governs driving under the influence in the state. Under that statute, it is unlawful for any person to drive a vehicle while under the influence of any drug. The law does not distinguish between illegal narcotics and prescription medications when it comes to impairment-based DUI charges. If the substance affects your physical or mental capabilities while you are behind the wheel, the statute applies.

This means a driver taking opioid painkillers after surgery, a benzodiazepine for anxiety, a muscle relaxant for a back injury, or even a strong antihistamine could face a DUI charge if an officer determines that the drug is impairing their driving. Having a valid prescription does not automatically prevent an impairment-based DUI charge. The question under the impairment provision is whether you were impaired, not simply whether your doctor authorized the medication.

How Officers Detect Prescription Drug Impairment

Officers look for signs of impairment during traffic stops, using field sobriety tests and Drug Recognition Experts trained to identify drug-affected drivers.

A standard breathalyzer will not detect prescription drugs. Because of this, law enforcement in Delaware uses other methods when officers suspect drug-impaired driving.

During a traffic stop, an officer may observe:

  • Slowed or slurred speech
  • Glassy, drooping, or dilated eyes
  • Delayed reaction times or confusion
  • Unusual behavior or an inability to follow simple instructions
  • Signs of physical imbalance or impaired coordination

If an officer suspects drug impairment, they may call in a Drug Recognition Expert, commonly referred to as a DRE. Delaware law enforcement agencies train DRE officers to conduct a structured evaluation that includes pulse rate checks, eye examination, and divided attention tests. A DRE evaluation is designed to assess whether a driver shows signs of impairment consistent with drug use and may help the officer identify a likely category of drug involved.

Officers may also seek chemical testing, including analysis of blood or urine for the presence of drugs. Delaware law permits evidence concerning the presence and concentration of drugs in a person’s blood, breath, or urine to be used in a DUI proceeding. For an impairment-based DUI charge, the State must prove that the drug caused the driver to be less able to exercise clear judgment, sufficient physical control, or due care while driving. Chemical-test results may be relevant evidence, but Delaware law does not require chemical testing to establish impairment.

Which Prescription Drugs Are Most Commonly Involved?

A wide range of prescription and over-the-counter medications can potentially affect a person’s ability to drive safely.

Medications that may affect alertness, coordination, reaction time, or judgment can become relevant in a drug-impaired driving investigation. Examples include:

  • Opioids such as oxycodone, hydrocodone, and morphine, which can cause drowsiness, slowed reaction time, and impaired judgment
  • Benzodiazepines such as Xanax, Valium, and Ativan, which affect coordination and cognitive function
  • Sleep medications such as Ambien, which carry warnings about next-morning impairment
  • Muscle relaxants such as Flexeril or Soma, which can cause significant sedation
  • Antihistamines such as diphenhydramine, found in many over-the-counter allergy and sleep products

Your prescribing physician may have told you not to drive while taking a medication. If that warning appears on the label or in the medication guide, a prosecutor may use it as evidence that you knew impairment was a risk.

What Are the Penalties for a Prescription Drug DUI in Delaware?

A first-offense DUI conviction in Delaware is punishable by a fine of $500 to $1,500, imprisonment of up to 12 months, or both, and a conviction also results in a 12-month revocation of the driver’s license or driving privilege.

Under Title 21, Section 4177, a first DUI offense is punishable by a fine of $500 to $1,500, imprisonment of up to 12 months, or both. A conviction also results in a 12-month revocation of the driver’s license or driving privilege under Section 4177A.

The court may also require the person to complete a drug and alcohol evaluation and an education or rehabilitation program as provided by Delaware law. Eligible first-time offenders may also have the option of a first-offender election under Delaware law, subject to statutory eligibility requirements and conditions.

A second offense carries a mandatory minimum of 60 days in jail, a longer license revocation, and steeper fines. Subsequent convictions escalate further. These are not minor consequences. A conviction can affect employment, professional licensing, and immigration status.

Can You Fight a Prescription Drug DUI Charge?

Yes. Common defenses include challenging the DRE evaluation, the legality of the stop, blood test accuracy, and whether actual impairment was established.

A charge is not a conviction. Several defense strategies may apply depending on the facts of your case. The DRE evaluation process is not infallible, and the methodology can be challenged. Blood test results may be contested based on how the sample was collected, stored, or analyzed. The legality of the traffic stop and subsequent investigation can also be challenged. If an officer lacked the required legal justification for a stop or search, evidence obtained as a result may be subject to suppression, depending on the circumstances.

The prosecution must prove that you were actually impaired, not just that a substance was present in your system. Many prescription medications remain detectable in blood long after their impairing effects have worn off. That distinction can be critical to your defense.

Talk to The Delaware DUI Defender

Facing a DUI charge for a prescription medication you were legally taking is a disorienting experience. The Delaware DUI Defender represents people throughout Dover and across Delaware who are facing DUI charges involving prescription medications. We understand how serious these charges can be and approach every case with the care it deserves. Call us at 302-865-8431 or contact us today to discuss your case.

 

Last updated: October 2026