Most of us know that driving on alcohol impairs the ability to operate a motor vehicle safely. But what you might not know is that you are also at risk for hurting or killing yourself or others if you are taking certain prescription or over-the-counter drugs, even if you are taking them as directed. Learn about the unforeseen consequences of everyday medications.
Every year Americans drive over a billion miles. We get into our cars and trucks and accelerate, steer and brake without realizing what a complex process it is. Driving requires countless nerve transmissions, connections and calculations shuttling back and forth between the eyes, brain and body to decide what to do at a moment's notice. It doesn't matter if you are motoring toward the drive-in window, swerving around a pothole, stopping behind a school bus or merging onto the highway. A driver's ability to navigate safely relies on a sound mind and body.
We already know the effects and consequences of impaired driving caused by alcohol and recreational drugs. The substances quickly barrage the brain to dampen reflexes and thinking, and mar the perception of surroundings. Drivers are unable to react swiftly to control the vehicle they are driving. But an alarming number of drivers are also putting themselves and others at risk of a crash because they are impaired by common over-the-counter (OTC) drugs and prescription medications legally prescribed by their doctors.
When the AAA Foundation for Traffic Safety performed a random of survey drivers they discovered that 72% of people over 55, an age group that is most likely to be taking medications for chronic conditions, had no idea that their driving performance could be affected by their medicines. Baby boomers are particularly at risk because they are more likely to take one or more medications routinely for common conditions like high blood pressure, osteoarthritis, abnormal cholesterol and diabetes. Nearly half of all 70 year-olds take up to 5 medications a day.
More than half of 50 year-olds take one or more potentially driver-impairing medications, or PDIs as they have come to be known, defined as drugs that could affect driving ability, even when they are taken as prescribed.
These individuals are unknowingly driving under the influence (DUI).
The AAA and US Department of Transportation's National Highway Traffic Safety Administration (NHTSA) expect that the problem caused by PDI medications will only worsen as the medicated middle-aged driving population increases as expected.
It is time to raise awareness of this growing problem and save lives.
How Drugs Can Affect Driving
There are many good drugs effectively treating medical conditions that have undesirable side effects when used as directed, and particularly when they aren't. A side effect imparts an effect that wasn't originally intended. If you have ever read the manufacturer's package labeling or insert you can see the known ones listed.
If you are taking a drug that has intended sedative characteristics – say a drug to quell anxiety, you would expect to become somewhat sedated. And that is true for many psychoactive drugs that target the brain and nervous system (these are called central nervous system or CNS drugs).
But sometimes the effects are unanticipated. You wouldn't think at first that a non-narcotic cough medicine, diabetes medication or drugs that lower high blood pressure would impact driving ability. But they can significantly lower blood pressure (hypotension) and blood sugar (hypoglycemia) and that can impair driving too.
Making drug effects even more uncertain is that everyone has their own physiology to contend with, personal ways the body absorbs, tolerates and metabolizes drugs. And drugs can also interact with other drugs in both known and unpredictable ways. The problem is, you won't know how your body will react to a drug until it is taken.
Potentially Driver-Impairing Drugs
Drugs that affect the brain, nerves, muscles, blood pressure, blood sugar and vision are particularly worrisome when taken by people who drive. They can impair decision-making and cause disorientation, confusion, fainting, dizziness, drowsiness, weakness, vision disturbances, headache, tremors and tingling.
In the NHTSA "Multiple Medications and Vehicle Crashes" report the authors examined the effect of OTC and prescription drugs on the risk of motor vehicle crashes: The risk was 7.50 times greater in people who took barbiturates (a CNS depressant), 3 times higher in people taking antihistamines (cold and allergy medications) and 2 times higher in people taking a common OTC non-narcotic cough medicine. The list of medicines containing PDI ingredients is surprisingly long. Some OTC remedies have more then one.
Examples of PDI Drugs
Drugs that work on the central nervous system
- Anticonvulsants (seizure drugs)
- Antianxiety drugs
- Barbiturates used for nervousness and seizures
- Antivertigo drugs
- Drugs for Parkinson's disease
Drugs for muscle, arthritis and menstrual pain
- Muscle relaxants
- Narcotic painkillers
Drugs for high blood pressure
- Ace Inhibitors
Drugs for allergy, asthma and colds
- Antihistamines (oral and for the eye)
- Cough suppressants and expectorants
Drugs for heart disease
- Platelet-reducing drugs (anticoagulants)
- Antiarrhythmia drugs
- Diabetes drugs (oral and insulin)
Drugs for gastrointestinal disorders
- Acid reducers
- Antispasmodic (cramps)
- Antidiarrheal drugs
Protecting Yourself (and Others)
No one is suggesting that after you read this you pull the plug on PDI medications you are currently taking. But it is important that you be being mindful of every drug you plan on putting in your body before you start taking them. This is a good way to keep the roads a safer place for you and others.
Checklist for Medication Users
- Take an inventory of all your OTC, prescription medications and dietary supplements you are taking. List their dosages and what you take and when.
- Read the label carefully. Look for warnings about sedation, fainting, dizziness, drowsiness, muscle weakness, loss of coordination and the need for caution when driving. Sedating ingredients can be found in many cough, cold, allergy, pain, nausea and gastrointestinal upset medicines.
- Make your pharmacist and all your prescribing healthcare providers aware of everything you are taking. Ask about their side effects and if there are any drug-to-drug interactions. Ask specifically if they are potentially driver impairing.
- Check the label and see if there is a specific warning, especially if you are buying a remedy off the drugstore shelf. Don't assume an OTC formula is safe for driving because it doesn't require a prescription. Some cold remedies say they are non-drowsy formulas, but the drowsy ones aren't always clearly labeled. You need to dig deep into the label to see what it contains (drugs containing dextromethorphan or diphenhydramine are a clue). When in doubt ask the pharmacist, even if it is OTC.
- Try and fill all prescriptions at the same pharmacy so that the pharmacist can flag unsafe combinations (both impairing and non-impairing).
- If you don't know how your body will react while taking a medication, don’t drive until you do. Get a designated driver instead or take public transportation.
Special Note: Although it is difficult to test for the presence of a legally prescribed or OTC drug using a test like a Breathalyzer which detects alcohol, driving under the influence of drugs (DUID) arrests and prosecution is possible. When impairment doesn't match the Breathalyzer result, and the driver appears impaired, law enforcement can request blood or urine sample that tests for drugs.