Drug DUI in Arizona: Charged With Driving Under the Influence of Drugs

Arizona prosecutes drug-impaired driving as aggressively as alcohol DUI – and in many ways, drug DUI cases are more dangerous for defendants. You can be convicted of a drug DUI in Arizona even if you were not impaired. Even if the drug was legally prescribed to you. Even if the substance was consumed days or weeks before you drove.

That is not hyperbole. It is the law.

At Rideout Law Group, founding attorney Brad Rideout is a former Arizona District Attorney who prosecuted drug DUI cases and knows exactly how the state builds these cases. That experience is now your advantage. If you have been charged with driving under the influence of marijuana, prescription medication, illegal drugs, or any combination of substances in Scottsdale or anywhere in Arizona, this page explains what you are facing and how we fight back.

Arizona’s Drug DUI Statutes

Arizona has two primary drug DUI provisions, and understanding the difference between them is critical to your defense.

A.R.S. § 28-1381(A)(1) – Impaired to the Slightest Degree

This statute makes it illegal to drive or be in actual physical control of a vehicle while impaired to the slightest degree by any drug, vapor-releasing substance, or combination of liquor, drugs, or vapor-releasing substances.

The key phrase is “impaired to the slightest degree.” Arizona does not require proof that you were significantly impaired or unable to drive safely. Any measurable impairment – even the slightest reduction in your ability to operate a vehicle – satisfies this element.

Under this provision, the prosecution must prove actual impairment. They typically rely on officer observations, field sobriety test performance, Drug Recognition Expert (DRE) evaluations, and sometimes dashcam or body camera footage.

A.R.S. § 28-1381(A)(3) – The Metabolite Provision

This is the statute that shocks most people. Under A.R.S. § 28-1381(A)(3), it is illegal to drive or be in actual physical control of a vehicle while there is any drug defined in A.R.S. § 13-3401 or its metabolite in your body.

Read that again: or its metabolite.

A metabolite is a byproduct your body produces as it processes a drug. Metabolites can remain in your system long after the drug’s effects have worn off. For marijuana, the inactive metabolite carboxy-THC can be detectable in blood for days or even weeks after last use. For other substances, metabolite detection windows vary but often extend well beyond any period of impairment.

Under the metabolite provision, the prosecution does not need to prove you were impaired at all. They only need to prove:

1. You were driving or in actual physical control of a vehicle
2. A prohibited drug or its metabolite was present in your body

That is it. Zero impairment required. This creates a situation where a person who used marijuana legally in their own home on Saturday night can be arrested and convicted of DUI on Tuesday afternoon while driving completely sober.

What Drugs Are Covered

A.R.S. § 13-3401 defines the substances that fall under Arizona’s drug DUI statutes. The list is extensive and includes:

• Marijuana and THC (including both active delta-9 THC and inactive metabolites)
• Prescription opioids (oxycodone, hydrocodone, fentanyl, morphine, codeine)
• Benzodiazepines (Xanax, Valium, Klonopin, Ativan)
• Sleep medications (Ambien, Lunesta)
• Stimulants (amphetamine, methamphetamine, cocaine)
• Hallucinogens (psilocybin, LSD, MDMA)
• Other controlled substances (heroin, PCP, ketamine, GHB)

The list also includes many substances that most people would never associate with a DUI charge, including certain over-the-counter medications when they contain controlled substance analogs.

Aggravated Drug DUI – A.R.S. § 28-1383

A drug DUI can be elevated to aggravated DUI – a class 4 felony – under several circumstances:

• DUI while your license is suspended, revoked, or cancelled
• Third DUI offense within 84 months (7 years)
• DUI with a person under 15 in the vehicle
• DUI while required to have an ignition interlock device
• Driving the wrong way on a highway while under the influence

Aggravated DUI carries mandatory prison time. This is not county jail – it is the Arizona Department of Corrections. The stakes escalate dramatically when aggravating factors are present.

Types of Drug DUI Cases

Marijuana DUI

Marijuana is the most common drug involved in Arizona DUI cases, and it presents unique legal issues – particularly after the passage of Proposition 207 (A.R.S. § 36-2852), which legalized recreational marijuana for adults 21 and older in November 2020.

The legal paradox: You can legally purchase marijuana from a licensed dispensary, consume it in your home, wait hours or days until you feel completely sober, drive your vehicle, and still be charged with DUI if any THC or THC metabolite is detected in your blood.

Proposition 207 legalized possession and use. It did not change the DUI statutes. Arizona law still treats the presence of any marijuana compound or metabolite in your blood as a basis for DUI prosecution.

Active THC vs. inactive metabolite: This distinction is at the heart of marijuana DUI defense.

• Delta-9 THC (active THC) is the psychoactive component that produces impairment. It is detectable in blood for a relatively short period – typically a few hours after consumption, though heavy users may have detectable levels for longer periods.
• Carboxy-THC (THC-COOH) is the inactive metabolite. It produces zero psychoactive effect and zero impairment. It can remain detectable in blood for days, weeks, or even longer in chronic users.

The Arizona Supreme Court addressed this issue in Dobson v. McClennen (2014), holding that the metabolite provision does not apply to the inactive metabolite of marijuana – only to substances that are capable of causing impairment. This was a significant ruling, but prosecutors continue to push the boundaries, and the distinction between active and inactive metabolites often becomes a contested scientific battle at trial.

Combination charges: Prosecutors frequently charge marijuana DUI under both A.R.S. § 28-1381(A)(1) (impairment) and A.R.S. § 28-1381(A)(3) (metabolite). If the metabolite charge fails under Dobson, the impairment charge may still proceed based on officer observations, field sobriety tests, and DRE evaluations.

Prescription Drug DUI

You have a valid prescription. You take your medication as directed by your doctor. You drive to work. You get pulled over. You get charged with DUI.

This scenario happens constantly in Arizona. Prescription medications that can trigger DUI charges include:

• Opioid painkillers: Oxycodone (OxyContin, Percocet), hydrocodone (Vicodin, Norco), morphine, fentanyl patches, codeine-containing medications
• Anti-anxiety medications: Alprazolam (Xanax), diazepam (Valium), clonazepam (Klonopin), lorazepam (Ativan)
• Sleep aids: Zolpidem (Ambien), eszopiclone (Lunesta), zaleplon (Sonata)
• Muscle relaxants: Cyclobenzaprine (Flexeril), carisoprodol (Soma)
• ADHD medications: Amphetamine/dextroamphetamine (Adderall), methylphenidate (Ritalin, Concerta)

Having a valid prescription is not an automatic defense under A.R.S. § 28-1381(A)(1). If the medication impairs you to the slightest degree, you can be convicted regardless of the prescription. However, a valid prescription is relevant to the A.R.S. § 28-1381(A)(3) metabolite charge and can be a significant factor in defense strategy.

Illegal Drug DUI

Cases involving illegal substances – cocaine, methamphetamine, heroin, fentanyl (without prescription), MDMA, and others – carry the same DUI penalties but create additional complications:

• The presence of the illegal drug itself may result in separate possession charges under Arizona drug statutes
• Prosecutors may use the illegal nature of the substance to argue consciousness of guilt
• Judges and juries tend to be less sympathetic to defendants involved with illegal substances
• Metabolite detection windows vary significantly by substance, creating the same “convicted while sober” problem seen in marijuana cases

Poly-Drug and Drug-Alcohol Combination DUI

When drugs and alcohol are combined, or when multiple drugs are detected, the case becomes more complex for both sides. Prosecutors argue synergistic effects – that the combination produces greater impairment than either substance alone. Defense teams can argue that the presence of multiple substances makes it impossible to attribute any observed impairment to a specific drug, complicating the prosecution’s burden of proof.

Drug Recognition Experts (DREs): What They Do and How to Challenge Them

When an officer suspects drug impairment but a breath test shows little or no alcohol, the next step is often a Drug Recognition Expert evaluation. DREs are law enforcement officers who have completed a standardized training program (developed by the LAPD and the National Highway Traffic Safety Administration) designed to identify drug impairment.

The 12-Step DRE Protocol

A DRE evaluation follows a 12-step protocol:

1. Breath alcohol test
2. Interview with the arresting officer
3. Preliminary examination and first pulse reading
4. Eye examinations (HGN, VGN, lack of convergence)
5. Divided attention tests (modified Romberg, walk-and-turn, one-leg stand, finger-to-nose)
6. Vital signs and second pulse reading
7. Dark room examinations (pupil size estimation)
8. Muscle tone examination
9. Injection site check and third pulse reading
10. Subject statements and interview
11. DRE opinion (drug category)
12. Toxicological examination (blood or urine)

Challenging DRE Evidence

DRE testimony is often the centerpiece of a drug DUI prosecution, and it is far more vulnerable to challenge than most defendants realize.

Qualification challenges: Not all DRE training is equal. Officers may have minimal experience, may not have maintained recertification requirements, or may have a track record of inaccurate drug category predictions. An experienced defense attorney will obtain the officer’s training records, certification history, and prior case outcomes.

Subjectivity: Many DRE evaluation steps are inherently subjective. Pupil size estimation is done by comparing the subject’s pupils to a printed card in varying light conditions. Muscle tone assessment relies on the officer’s tactile judgment. Vital sign readings can be affected by anxiety, physical exertion, medications, and medical conditions unrelated to drug use.

Medical condition mimicry: Numerous medical conditions produce symptoms that mimic drug impairment:

• Diabetes and blood sugar fluctuations
• Neurological conditions (MS, Parkinson’s, neuropathy)
• Inner ear disorders affecting balance
• Fatigue and sleep deprivation
• Eye conditions affecting pupil response
• Anxiety and panic disorders
• Head injuries and concussions

Confirmation bias: DREs are called to the scene because drug impairment is already suspected. They arrive predisposed to find impairment. Studies have shown that this confirmation bias can influence evaluation outcomes.

Toxicology discrepancies: The DRE makes a prediction about which drug category is involved before the toxicology results come back. When the toxicology results do not match the DRE’s prediction, it undermines the officer’s credibility and the reliability of the entire evaluation.

The Metabolite Problem: Convicted While Sober

Arizona’s metabolite provision under A.R.S. § 28-1381(A)(3) creates a legal landscape that most people find difficult to believe until they are caught in it.

Consider these real-world scenarios:

• A medical marijuana patient takes their medication on Friday evening, drives to a Monday morning appointment, gets pulled over for a broken taillight, and tests positive for THC metabolite. Charged with DUI.
• A patient recovering from surgery takes their last prescribed Percocet on Wednesday. Their body continues to metabolize the opioid. On Saturday, they are involved in a minor fender-bender. Blood draw reveals opioid metabolite. Charged with DUI.
• A college student uses cocaine at a party on Saturday night. By Monday, they feel completely normal. A routine traffic stop leads to a blood test that reveals benzoylecgonine (cocaine metabolite). Charged with DUI.

In none of these scenarios was the driver impaired. In all of them, the driver can be prosecuted and convicted under Arizona law.

The Dobson Exception for Marijuana

The Arizona Supreme Court’s ruling in Dobson v. McClennen (2014) created a narrow but important exception: the metabolite provision does not apply to the non-impairing metabolite of marijuana (carboxy-THC). Prosecutors must show the presence of an impairing substance – either active THC or evidence of actual impairment.

This ruling applies only to marijuana metabolites. For all other controlled substances, the metabolite provision remains fully in effect.

Defense Strategies for Drug DUI

Brad Rideout built DUI cases as a prosecutor. He knows where the weaknesses are. Effective drug DUI defense targets multiple pressure points simultaneously.

Challenge the Traffic Stop

Every DUI case begins with a stop. If the stop was unlawful – no reasonable suspicion, no observed traffic violation, improper checkpoint procedures – all evidence obtained after the stop can be suppressed through a motion to suppress. Without the evidence, the case cannot proceed.

Challenge Metabolite-Only Evidence

If the prosecution is relying solely on metabolite evidence under A.R.S. § 28-1381(A)(3), the defense can argue:

• The metabolite detected was non-impairing (particularly for marijuana under Dobson)
• The presence of metabolite does not establish when the drug was consumed
• No evidence connects the metabolite to any impairment at the time of driving

Valid Prescription Defense

A valid prescription, while not an absolute defense, significantly complicates the prosecution’s case. The defense strategy involves demonstrating:

• The medication was prescribed by a licensed physician
• The defendant was taking the medication as directed
• The prescribing physician did not advise against driving
• No evidence of impairment beyond the mere presence of the substance

Challenge DRE Qualifications and Methodology

As outlined above, DRE evaluations have multiple vulnerability points. A thorough defense examines the specific officer’s training, experience, accuracy rate, and adherence to the 12-step protocol.

Challenge Laboratory Testing

Blood and urine testing is not infallible. Defense challenges include:

• Chain of custody: Was the sample properly handled, stored, and transported from the draw to the laboratory to the courtroom?
• Laboratory accreditation and procedures: Is the lab accredited? Were standard operating procedures followed?
• Contamination: Was the blood draw site cleaned with a non-alcohol antiseptic? Were samples properly sealed?
• Quantitative vs. qualitative results: Was the test designed to detect the mere presence of a substance, or to measure its concentration? The distinction matters for impairment arguments.
• Detection thresholds: Different labs use different cutoff levels. A result that is “positive” at one lab may be “negative” at another.

Prove No Actual Impairment

For charges under A.R.S. § 28-1381(A)(1), the prosecution must prove impairment. Defense evidence that undermines the impairment claim includes:

• Dashcam or body camera footage showing normal driving and normal behavior during the stop
• Performance on field sobriety tests (many people perform poorly on these tests while completely sober)
• Absence of driving pattern consistent with impairment
• Witness testimony about the defendant’s behavior and sobriety before driving

Frequently Asked Questions

Can I get a DUI for taking my prescribed medication?

Yes. Arizona law does not exempt prescribed medications from DUI prosecution. If the medication impairs your ability to drive to the slightest degree, you can be charged and convicted under A.R.S. § 28-1381(A)(1). The presence of the medication or its metabolite can also support charges under A.R.S. § 28-1381(A)(3).

Is marijuana DUI still a crime after Proposition 207 legalized recreational use?

Absolutely. Proposition 207 legalized the possession and use of marijuana for adults 21 and older. It did not legalize driving under the influence of marijuana. If you have active THC or impairing metabolites in your system while driving, you can be charged with DUI.

What is the difference between active THC and THC metabolite?

Active delta-9 THC is the psychoactive compound that produces the “high” and can cause impairment. Carboxy-THC (THC-COOH) is the inactive metabolite your body produces after processing THC. The inactive metabolite causes zero impairment and can remain in your system for days or weeks. Under the Dobson ruling, the inactive metabolite alone cannot support a DUI conviction in Arizona.

How long do drugs stay in your system for DUI purposes?

Detection windows vary dramatically by substance:

• Marijuana (active THC): Hours to a few days in blood
• Marijuana (metabolite): Days to weeks in blood; up to 30+ days in urine for heavy users
• Cocaine metabolite: 2 to 4 days in blood
• Opioid metabolites: 1 to 4 days in blood depending on the specific drug
• Benzodiazepine metabolites: Days to weeks depending on the specific drug
• Methamphetamine metabolite: 2 to 5 days in blood

What happens if I refuse the blood test?

Under Arizona’s implied consent law (A.R.S. § 28-1321), refusing a chemical test triggers an automatic 12-month license suspension. Additionally, law enforcement can obtain a warrant for a blood draw, meaning they may take your blood regardless of your refusal. Refusal can also be used as evidence of consciousness of guilt at trial.

Can a drug DUI be charged as a felony?

A standard drug DUI is a misdemeanor. However, under A.R.S. § 28-1383, a drug DUI becomes an aggravated DUI (class 4 felony) if aggravating factors are present, including a third DUI within 84 months, driving on a suspended license, having a minor under 15 in the vehicle, or driving the wrong way on a highway.

Should I tell the officer about my prescription medications during a traffic stop?

Consult with an attorney before making statements to law enforcement. Voluntarily disclosing prescription medication use provides the officer with information that can be used to establish probable cause and build a DUI case. You have the right to remain silent. Exercise it, and contact an attorney.

Do Not Wait to Get Legal Help

Drug DUI cases are scientifically and legally complex. The prosecution will have toxicology reports, DRE evaluations, and officer testimony. You need a defense team that can challenge every piece of that evidence on both legal and scientific grounds.

Brad Rideout is a former prosecutor who built drug DUI cases from the other side. He knows how prosecutors think, what evidence they rely on, and where that evidence falls apart under scrutiny.

Call Rideout Law Group now for a confidential consultation:

• Scottsdale: (480) 584-3328
• Lake Havasu City: (928) 854-8181
• Toll-Free: (833) 854-8181

Scottsdale Office

11111 N Scottsdale Rd, Suite 225

Scottsdale, AZ 85254

Lake Havasu City Office

2800 Sweetwater Ave, Suite A-104

Lake Havasu City, AZ 86406

A drug DUI charge is not a conviction. But only if you fight it. Call today.