A man examines a prescription medication that has been legally prescribed to him.
Published On: September 12, 2019|Categories: DUI/DWI|

Most often, when we think about DUI charges, we think of driving while under the influence of alcohol or illegal substances. But can you also be charged with a DUI for driving while on legally prescribed drugs?

While there are variations in each state’s laws, the answer is generally yes, you can get charged with driving while intoxicated for operating a vehicle while on prescription drugs. This is because states make a distinction between two types of DUI charges – “per se” and “impairment.” 

Per se and impairment charges

In order to receive a DUI charge, the driver must be both:

  • Operating or driving a vehicle;
  • Intoxicated or under the influence.

These requirements lead to the either a per se and impairment charge. It’s important to know the difference between both charges to understand why some medications, despite being legally prescribed to you, can result in a DUI charge.

Per se DUI charge

A per se DUI is based upon the concentration of a substance in the driver’s blood. Typically, this will mean a driver’s blood alcohol count (or BAC). For example, in every state it is illegal to operate a vehicle with a BAC of .08% or higher.

Additionally, some states have established blood concentration limits for other substances, such as marijuana, cocaine and methamphetamine.

If a driver’s BAC or other substance concentration is over the state’s legal limit, whether they are visibly impaired or not, they will receive a DUI charge. It is important to note that, for per se DUIs, there is no need to prove impairment so long as the driver is over a legally established limit.

However, what happens when a driver is impaired by a drug, but the substance is a legal substance? This is when an impairment charge is applicable.

Impairment DUI charge

It is illegal to operate a vehicle while intoxicated or under the influence. According to every state’s laws, “under the influence” applies to more than alcohol or illegal drugs; it is also applicable to any substance that can cause impairment in a driver, including prescribed or over-the-counter medications.

In other words, if a police officer has reason to believe a person is driving while in an impaired mental or physical state, they can perform a substance test or even a field sobriety test. Poor performance during a field sobriety test is often used as evidence of driver impairment.

In cases where a driver’s substance tests come back clean, but they are still clearly impaired, the driver can still be charged with a DUI.

What Is impairment?

There are many substances which can cause impairment in an individual, including prescription drugs.

The National Highway Traffic Safety Administration (NHTSA) defines impairment as any state under which an individual drives differently and less safely than they normally would. The NHTSA also states that even over-the-counter medicines can cause impairment and therefore result in a DUI charge.

Common signs of impairment include:

  • Extreme levels of drowsiness;
  • Dizziness;
  • Decreased hand-eye coordination;
  • Slower reaction time.

If you are unsure whether or not you are impaired by a medication, the NHTSA says it clearly – “If you feel different, you drive different.”

It is important to always be aware of warning labels on medication that advise the user against operating heavy machinery or vehicles. Doing so can help prevent a DUI and, most importantly, keep you and others safe.

How is impairment measured and proven?

Since an impairment DUI does not solely rely on any form of blood concentration testing, the criteria for proving impairment typically consists of a field sobriety test or other tell-tale signs of intoxication, including:

  • Erratic driving;
  • Unusual behavior;
  • Slurred or noticeably slow speech;
  • Red, glazed or droopy eyes;
  • Inability to focus or recall details.

Some of the above items are also part of traditional field sobriety testing.

It is important to note that every state has impairment DUIs; however, states vary in the level of impairment for a DUI charge. In some states, a driver must only be proven to be intoxicated to the “slightest degree,” while in other states, a driver must be impaired to an “appreciable degree” in order to receive a DUI conviction.

Regardless of the degree to which a driver must be impaired, one thing is universally true: all states consider impairment, whether caused by an illegal or legal substance, to be a driving under the influence.

Prescription drugs and substance abuse

Many people need to take prescriptions for a medical condition. However, prescription drugs can be abused. There are some noticeable signs of prescription drug abuse, a DUI charge being one of them. If you or a loved one has had one or more convictions for driving under the influence of drugs, it’s possible that a substance use disorder is the underlying cause.

However, help is available and recovery is possible. To speak with a specialist today, consider reaching out to Rehab After Work. Whether you want to gain specific information about our Addiction Awareness and DUI Programs, or just gather general information, we are here for you. Contact us anytime by calling 610-644-6464 and schedule your first appointment today.


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