A prescription drug DUI allegation asserts that a driver’s ability to safely operate a vehicle was impaired by a medication, whether lawfully prescribed or over-the-counter. Proving impairment typically involves officer observations of driving and behavior, field sobriety testing, and chemical testing such as blood or urine analysis. Courts consider whether the medication in question likely affected driving performance at the time of the stop and whether proper procedures were followed during evidence collection and testing. Every situation is different, and the presence of medication in a sample does not automatically prove impairment. Timing of ingestion, dosage, interactions with other substances, and medical conditions all matter. A careful review of records and testing procedures is necessary to determine how strong the prosecution’s case is and what defenses may be available in Jasper County courts.