Can I get a DUI on prescription medication?

The premise that a lawful prescription makes driving lawful is wrong, and it's a costly assumption.

Florida's DUI statute covers driving while under the influence of alcoholic beverages, chemical substances, or controlled substances, to the extent that normal faculties are impaired. A prescription establishes that possession was legal. It says nothing about whether the person was impaired while driving.

Medications that commonly produce these cases: sleep aids, muscle relaxers, anti-anxiety medications, opioid pain medication, and some antihistamines. Interactions between prescriptions, or between a prescription and a small amount of alcohol, produce effects neither would alone.

The same applies to medical marijuana. A card authorizes possession under defined conditions; it doesn't authorize impaired driving.

What differs from an alcohol case is proof. There's no breath instrument for these substances and no equivalent of the .08 threshold, so the State relies on officer observation, drug recognition evaluation, and urine or blood testing.