Alcohol and other drugs impair judgment, vision, reflexes and alertness. In Missouri, you can be charged with DWI for driving impaired by alcohol, illegal drugs, prescription or over-the-counter medicine, or any combination of these.
Know the rule
The law doesn't distinguish between prescription, over-the-counter and illegal drugs: driving on any drug that impairs your ability to drive safely is illegal. DWI penalties are exactly the same for drugs as for alcohol.
Handbook p. 73 ↗Know the rule
DWI punishment is up to six months in prison, a fine of up to $500, and loss of driving privileges.
Handbook p. 73 ↗Alcohol:
- Slows reflexes and reaction time
- Affects vision: slows eye muscles, alters perception, impairs night vision
- Causes drowsiness and reduces concentration and attention
- Impairs coordination, comprehension and rational decision-making
Medications:
- Any prescription or over-the-counter medicine can impair driving, even taken as directed
- Cold and allergy medicines can make you drowsy
- Pep pills, "uppers" and diet pills: brief alertness, then nervousness, dizziness, poor concentration
- Don't drive after taking any drug that "may cause drowsiness or dizziness"
- Don't mix medications unless your doctor directs, and never mix them with alcohol
- Never take medicine prescribed for someone else; it's dangerous and illegal
Know the rule
It's your responsibility to know how your medications affect you. If unsure, check with your physician or pharmacist and read the warning label.
Handbook p. 73 ↗Know the rule
Marijuana is the second most cited drug in car crashes, after alcohol. Although medical marijuana was approved effective 2020, it's never legal or safe to drive under its influence.
Handbook p. 74 ↗Know the rule
Marijuana impairs thinking, judgment of time and distance, and coordination. Studies show more lane weaving, poor reaction time and altered attention, and combining it with alcohol impairs drivers even more.
Handbook p. 74 ↗Substance use disorder
Recurrent use of alcohol and/or drugs causing significant impairment, such as health problems, disability or failing major duties at work, school or home.
Handbook p. 74 ↗Know the rule
Help is available through the SAMHSA National Helpline, 1-800-662-HELP (4357): free, confidential, 24 hours a day, 365 days a year. Early use is one of the greatest predictors of addiction.
Handbook p. 74 ↗Put it into practice
This morning you took an allergy pill labeled "may cause drowsiness." Don't drive: it can impair you, and a DWI caused by medicine carries the same penalties as one caused by alcohol.