Metabolite DUI: Driving With a Measurable Controlled Substance

Police test for blood-alcohol concentration (BAC) at a typical DUI/DWI stop. These sobriety tests aren’t perfect, but they’re relatively accurate. But alcohol is just one of the countless substances that can cause impairment.

Others, such as marijuana, heroin, and even legal prescription painkillers, are more difficult to measure. Many of these drugs stay in the system much longer than alcohol — long after they stop causing impairment. This challenges police officers to determine accurate impairment levels at a precise time.

This article discusses drug-related DUIs and metabolites. It also addresses driving under the influence of marijuana. Finally, it discusses state approaches to measuring controlled substance use by drivers.

If you’re up against DUI charges, get more detailed advice for your case. Ask for a DUI defense lawyer’s perspective to better understand your options. They can explain how to fight the charges or minimize the consequences.

What Are Metabolites?

Metabolites are chemicals that appear in a person’s body as it processes a substance. There are many different types of metabolites. In the context of DUI laws, metabolites generally refer to the byproducts of alcohol, prescription drugs, and illegal drugs.

Sometimes, these metabolites can be present in the body for a long time after you use a substance. They could still be present when you’re sober or when the main effects of a drug have worn off.

Police must base DUI charges on evidence. Metabolites offer proof that the offender metabolized a certain amount of a given substance at a given time.

Metabolites in Alcohol DUI Cases

Breathalyzer and chemical tests don’t directly measure the amount of alcohol in your bloodstream. Instead, they measure the concentration of the metabolites alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH).

Your body metabolizes alcohol at a relatively fast rate of roughly .016 percent (or one average alcoholic drink) per hour. As a result, this measurement gives a reasonably accurate snapshot of a driver’s BAC during a motor vehicle traffic stop.

Metabolites in Drug-Related DUI Cases

In contrast to alcohol, legal or illegal drugs work differently. They break down into their own unique metabolites. There are ways to detect and accurately measure those metabolites.

As a result, many states have a “zero tolerance” or per se approach to non-alcohol DUI charges. This means a motorist who isn’t impaired at the time of a traffic stop may still be guilty of driving under the influence of drugs. This applies if the metabolites are present at the time of the stop. State law may limit metabolites either above a certain level or at any detectable level.

Testing for Marijuana DUIs

Marijuana, also known as cannabis, is the second most common substance in DUI cases. But it is much more challenging to measure in the context of a DUI investigation than alcohol.

Marijuana use is legal in some states, but “stoned driving” is illegal in every state. States that allow recreational or medical marijuana still need to protect public safety. Many states will arrest DUI suspects who have any measurable level of THC (the psychoactive component of marijuana) in their blood. The limit will depend on state DUI laws.

How Long Does Marijuana Stay in the Body?

Marijuana metabolites remain in the bloodstream (as measured in urine) for roughly one week after ingestion. The specific timing can vary based on your metabolism and frequency of cannabis use. The duration is long even though the high from marijuana may only last a few hours.

The timing can make it difficult to prove whether you were sober or high when police stopped you. That’s why the presence of marijuana metabolites in a urinalysis needs supporting evidence from a drug recognition expert.

Other evidence of intoxication could consist of behavior such as:

• Erratic lane changes
• Bloodshot eyes
• Slowed speech

The legal use of medical marijuana is no defense against DUI charges if the use causes impairment or if the state has a per se DUI statute.

Will My Ignition Interlock Device Detect Marijuana?

No. Generally, court-ordered ignition interlock devices (IIDs) are designed to detect alcohol metabolites. Their purpose is to stop someone with a prior conviction of a DUI from driving while drunk. These IIDs won’t get a positive alcohol reading from THC use because they have different metabolites.

Be aware that smoke and other strong contaminants in your breath may damage an IID. A damaged device may lead to errors and accidental lockouts.

State Limits for Controlled Substances While Driving

Some states take a zero-tolerance approach to impaired driving, regardless of the impairment of the driver at the time of a stop. The list of states with zero-tolerance drugged driving laws includes (but is not limited to) Iowa, Georgia, Arizona, and Michigan.

A zero-tolerance law means any detectable drug metabolite revealed through urine or blood screening can result in a DUI charge. Typically, there is other evidence of impairment. Blood draws are much less common, given how intrusive they are. State courts differ in how police may compel a blood draw after a DUI arrest.

Other states have a more nuanced approach to the assessment of drug impairment. Often, there are per se limits for certain drugs, such as marijuana.

These states include (but aren’t limited to) the following:

• Nevada: Per se impairment levels of 2 nanograms per milliliter of marijuana or 5 nanograms per milliliter of marijuana metabolite in a driver’s blood only apply when the violation is punishable as a felony
• Pennsylvania: Per se impairment for THC above 1 nanogram, any detectable level of other drugs (marijuana is illegal in the state)
• Montana: Per se impairment if the government has a blood test that shows a whole blood content of 5 nanograms per milliliter or more of active THC

Many states, including California, have two separate charges related to DUI. One charge is for having a BAC higher than 0.08 percent, and the other pertains to other evidence of impairment.

That means police can charge you with a DUI in California for:

• Showing clear signs of impairment (regardless of BAC or metabolite content)
• Having a BAC higher than 0.08 percent (or a detectable amount of drugs)
• Showing clear signs of impairment and having a BAC higher than 0.09 percent

There’s no immediate breath test for drugs other than alcohol. But law enforcement officers can use either blood or urine to screen for most drugs.

Metabolite DUIs While Traveling Between States

Driving between states requires you to obey the DUI and traffic laws in each state. Since metabolites can remain in your body for a long time, you’ll need to understand how to avoid a DUI.

For example, say you live in Sacramento, but you’re driving to Salt Lake City on a road trip. The Nevada and Utah DUI laws will apply once you cross each state line. While California police would need signs of actual impairment for DUI charges, Utah code has a zero-tolerance rule. If a Utah patrol officer smells marijuana on you or your car, they may have probable cause to arrest and test you for metabolites. Even if the last time you used marijuana was two days ago back in Sacramento, you might face a class B misdemeanor in Utah.

If you are arrested for impaired driving in another state, get a DUI attorney who knows that state’s legal system. Your lawyer can help you navigate the specific challenges of your DUI defense case.

Contact a Lawyer About Your Driving Under the Influence Charge

Suppose you’re driving while exceeding a certain level of drug metabolites. In that case, police can file a drunk driving or DUI charge against you regardless of actual impairment.

A DUI conviction can have far-ranging consequences for your life. Get professional help today from an experienced DUI lawyer.

A criminal defense attorney can walk you through your DUI case and help you craft a defense, whether dealing with a first offense, second offense, misdemeanor, or felony. A defense lawyer can help assert affirmative defenses and help you avoid a lengthy driver’s license suspension.