Florida DUI Drug Laws and How Over-the-Counter Medicines Can Lead to Unfair Arrests

If you’ve been arrested in Florida for driving under the influence of drugs, and the only substance you took was an over-the-counter allergy medication, you’re not alone. Many of my clients come to me shocked and confused, wondering how a simple antihistamine landed them in handcuffs. As a criminal defense attorney who’s handled DUI drug cases for years, I’ve seen firsthand how substances like Benadryl or Zyrtec can impair driving performance in ways that mimic alcohol or illegal drug intoxication. What the police see as impairment may actually be a side effect of a legal medication taken for a legitimate health issue.

But under Florida law, even legal drugs can lead to a DUI charge. That’s why it’s critical to have a private attorney who understands the science, the statutes, and the defenses available to fight these charges.

Florida’s DUI Drug Statute: It’s Not Just About Alcohol or Illegal Drugs

Florida Statute § 316.193 sets the foundation for all DUI charges, whether alcohol or drug-related. The statute makes it unlawful to drive or be in actual physical control of a vehicle while under the influence of alcohol, a chemical substance, or a controlled substance, when affected to the extent that your normal faculties are impaired.

Statute Text – Florida Statute § 316.193(1)(a):
"A person is guilty of the offense of driving under the influence… if the person is driving or in actual physical control of a vehicle within this state and… the person is under the influence of alcoholic beverages, any chemical substance… or any controlled substance… when affected to the extent that the person’s normal faculties are impaired."

This definition includes prescription drugs and even legal, over-the-counter medications. In other words, if an officer believes your ability to see, hear, walk, balance, or make decisions is impaired due to medication, you can be arrested—even if you followed the instructions on the box.

That is why people often don’t realize they’ve violated the law. They didn’t drink, didn’t take anything illegal, and didn’t feel impaired. But to the officer, slurred speech, drowsiness, or delayed responses might suggest impairment. This is where your defense starts.

Why Allergy Medications Can Mimic DUI Symptoms

Antihistamines such as diphenhydramine (the active ingredient in Benadryl) are widely used to relieve allergy symptoms like sneezing, watery eyes, or itching. But they can also cause:

  • Drowsiness

  • Dizziness

  • Slowed reaction time

  • Poor motor coordination

  • Difficulty concentrating

These side effects can resemble those of alcohol or controlled substances. If a driver is pulled over and appears confused or groggy, law enforcement may assume impairment without confirming whether the cause is a legal drug.

This is where police often make mistakes, and where an experienced private attorney can push back. The government must prove that your ability to operate a vehicle was impaired. That requires more than just an officer's suspicion or a vague field sobriety test.

Real Case Example: DUI Charge Dismissed After Proving Lawful Allergy Medication

A client of mine—a nurse with a clean driving record—was stopped late at night after drifting slightly in her lane. The officer claimed she appeared sleepy and had red, glassy eyes. She admitted to taking Benadryl that morning for seasonal allergies.

The arresting officer conducted field sobriety tests and claimed she failed them. She was charged with DUI, even though her breath test came back 0.00. No blood test was taken at the time of arrest.

We obtained the dash cam footage, which showed her driving pattern was minimal and her speech was clear. We presented medical records showing she had a history of allergies and had purchased the medication lawfully. We also brought in a pharmacologist who explained that diphenhydramine can cause certain symptoms without necessarily impairing driving ability.

After several hearings and filing a motion to suppress, the prosecution dropped all charges. She kept her license, her job, and her clean record.

This case is a clear example of how early intervention by a private attorney can stop an unfair prosecution before it ruins someone’s life.

Common Defenses in Allergy Medication DUI Cases

Defending against DUI drug charges tied to legal allergy medications requires a detailed approach. The police and prosecution often rely on general observations and flawed testing. Here's how we fight back.

Lack of Proof of Impairment

Florida law requires more than just the presence of a substance in your system. The state must show that your normal faculties were impaired. If you weren’t swerving, speeding, or otherwise driving erratically, and if field sobriety test results are questionable, we challenge whether any real impairment existed.

Legal Use of a Non-Controlled Substance

Antihistamines are not Schedule I or II controlled substances. Taking them legally, according to package instructions, is not a crime. We emphasize to the court that no illegal conduct occurred and no intent to drive impaired was present.

Faulty or Subjective Observations

Police often misread symptoms. Drowsiness or fatigue might come from long hours at work, not from drugs. Red eyes can be caused by allergies themselves, not medication. We confront the arresting officer with alternative explanations supported by evidence.

Unreliable Field Sobriety Tests

These tests are highly subjective and often performed on the roadside at night, in poor lighting, and under stressful conditions. Medical conditions, poor balance, or even anxiety can lead to poor performance. We may use video footage to demonstrate that the testing was unfair or inconclusive.

Why You Need a Private DUI Attorney for Drug-Related Charges

Public defenders are often skilled, but they work with heavy caseloads and limited resources. DUI drug cases involving legal medications require time, medical knowledge, expert consultations, and a strategic challenge to the arresting officer’s conclusions.

As your private attorney, I do more than show up in court. I investigate every aspect of the case—dash cam footage, 911 call logs, arrest reports, medical history, and any toxicology results. I bring in independent toxicologists and pharmacologists when needed. I file suppression motions when evidence is weak or procedures weren’t followed.

This kind of defense can mean the difference between walking free or carrying a criminal record for the rest of your life.

Musca Law, P.A. has a team of experienced criminal defense attorneys dedicated to defending people charged with a criminal or traffic offense. We are available 24/7/365 at 1-888-484-5057 for your FREE consultation. We have 30 office locations in Florida and serve all counties in Florida.

DUI Frequently Asked Questions

Can I be charged with DUI for taking over-the-counter allergy medication?
Yes, even legal medications like Benadryl or Zyrtec can result in DUI charges if law enforcement believes the drug impaired your ability to drive safely. Florida law does not require that the substance be illegal—only that it impairs your normal faculties. That’s why it’s important to work with a lawyer who can show the difference between side effects and true impairment.

Is there a difference between DUI for drugs and DUI for alcohol in Florida?
The statute is the same, but the proof is different. Alcohol DUIs typically involve breath tests, while drug DUIs rely on officer observations and sometimes blood or urine tests. This makes drug DUIs more subjective, and sometimes more defensible, especially when legal medications are involved.

What if I didn’t know the medicine would make me drowsy?
Lack of knowledge may not prevent a DUI arrest, but it can affect whether the prosecution can prove intent or impairment. Many people don’t realize that some antihistamines cause fatigue. A private attorney can present evidence that you had no intent to drive while impaired and were using the medicine legally.

Do I have to submit to a blood or urine test in a drug DUI case?
Under Florida’s implied consent law, you may be required to submit to a urine or blood test if police suspect drug impairment. Refusing can lead to a license suspension. However, there are defenses to refusal, and we review whether law enforcement had probable cause to request the test in the first place.

Can the allergy itself cause symptoms that appear as impairment?
Absolutely. Allergies can lead to red eyes, sneezing, fatigue, and even watery eyes or confusion. We’ve argued successfully that these symptoms were due to the allergy, not the medication. Having an attorney who understands the medical background is crucial in presenting this defense.

Will this go on my permanent record if I’m convicted?
Yes. A DUI conviction will appear on your criminal record and driving history. It can affect your insurance, employment, and professional licensing. Florida law does not allow DUI convictions to be sealed or expunged. That’s why an aggressive defense to avoid conviction is so important.

Is a DUI based on allergy medication a misdemeanor or a felony?
A first-time DUI offense, even one involving legal medication, is typically a misdemeanor. However, if there’s property damage, injury, or prior convictions, it can become a felony. Each case is different, and the facts matter. We analyze every element to see if felony charges can be reduced or dismissed entirely.

What kind of evidence does the prosecution use in these cases?
They typically rely on field sobriety test results, officer observations, body cam or dash cam video, and any test results from blood or urine. We challenge each of these pieces of evidence, particularly when the substance involved is not a controlled drug.

Can I fight the charge if I failed the field sobriety test?
Yes. Field sobriety tests are notoriously unreliable, especially for people with medical issues, anxiety, or fatigue. We often show that the conditions under which the test was administered were unfair or that the officer’s interpretation was incorrect.

Do I need a lawyer if I know I didn’t do anything wrong?
Yes, because being innocent doesn’t stop the process. Police, prosecutors, and courts operate based on the evidence presented. Without a strong defense, even an innocent person can be convicted. A private lawyer can help you avoid that outcome by controlling the evidence and the narrative before it’s too late.

Contact Musca Law 24/7/365 at 1-888-484-5057 For Your FREE Consultation

Musca Law, P.A. has a team of experienced criminal defense attorneys dedicated to defending people charged with a criminal or traffic offense. We are available 24/7/365 at 1-888-484-5057 for your FREE consultation. We have 30 office locations in Florida and serve all counties in Florida.