Is Driving Under The Influence Of Over The Counter Medication DUI?


When using this product:

  • marked drowsiness may occur
  • be careful when driving a motor vehicle or operating machinery

Those are some of the warnings on an over-the-counter box of Benadryl.

What most California drivers do not know is that it is possible to be arrested and charged with driving under the influence (DUI) of Benadryl. Yes, under California law[1] if an officer has probable cause to believe that your driving was impaired and you test positive for any amount of a drug that could affect your ability to drive —whether it is illegal, prescription, or over-the-counter—you can and probably will be charged with driving under the influence of a drug.

A drug under California vehicle code is any substance that affects a person’s mental or physical abilities to the extent that the ability of a person to drive using ordinary care is appreciably impaired by the substance. So for example, if a drug affects a driver’s reaction times, ability to judge distances or speeds, or causes erratic driving, that person is driving under the influence in violation of the law—whether the impairment is caused by the taking of an over-the-count drug such as Benadryl for an allergy or a prescribed psychiatric SSRI for depression, or an illegal psychoactive drug, such as methamphetamine.

There is no chemical test that can be administered in the field that tests for the presence of drugs in a driver’s system; therefore, if an officer believes you are under the influence of a drug and that the drug has affected your ability to drive safely, you will be required to submit to a blood (or maybe urine) test at the police station or other designated facility. Under California’s implied consent law, refusal to take the chemical test will result in an immediate and extended suspension of your driver license among other sanctions.

The chemical test, usually a blood test, will reveal the presence of drugs, even a drug such as Benadryl. And unlike the laws governing driving under the influence of alcohol, which sets a threshold of .08% blood alcohol content, there is no minimum limit under which a person may drive with a drug in his or her system if that drug affects the driver’s ability to drive. There are two sides to this coin: 1) a zealous prosecutor can go after a driver with any amount of drugs showing in his or her system and 2) it is easier to defend such charges since the presence of drugs is only one factor to be considered in light of the totality of the circumstances.

While I have not yet defended a client who was arrested for driving under the influence of Benadryl, I will not be surprised when that person walks into my office. I have, however, represented drivers who were arrested for driving under the influence of prescription drugs. Often these clients have been prescribed a drug that they take every day (an anti-depressant, for example) and they had no idea that it was illegal to drive if these drugs affected their ability to drive safely. They reasonably assumed that if the drug is legal, it is okay to drive.

We live in a world where it is estimated that 60% of the adult population is taking some kind of prescription medication and many more are using over-the-counter remedies. It is likely that you are either prescribed medication or use over-the-counter drugs. If the drug you take includes a warning that may affect your ability to drive, it is wise to self-assess your driving ability before you get behind the wheel—even if you are taking a drug as seemingly innocuous as Benadryl. If you are on prescription medication or advised to take certain over-the-counter medications, speak with your doctor about the effect the drug might have on your ability to drive safely. We often think of drunk drivers as the menace on the road but we rarely realize that drugs—even legal ones—can affect a person’s ability to drive safely.

William Weinberg has extensive experience defending those who have been charged with driving under the influence. Please feel free to contact him to set up a confidential consultation without charge at or by phone at (949) 474-8008.



[1] California Vehicle Code § 23152(e): “It is unlawful for a person who is under the influence of any drug to drive a vehicle.”



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