Medication and Driving: Which Prescriptions Impair Your Ability to Drive?

How medications impair driving

Several effects matter. Sedation reduces reaction time and concentration. Blurred vision affects judgment of distance and hazard recognition. Dizziness affects balance and steering control. Slowed cognitive processing affects decision making at intersections and in traffic. Some medications produce all of these simultaneously. Combinations multiply the effect.

The medications most likely to impair driving

Opioids

Hydrocodone, oxycodone, morphine, fentanyl, tramadol, and codeine all impair driving, especially in the first days of starting or after a dose increase. Even patients who feel adjusted to chronic opioid therapy show measurable impairment in driving simulator studies.

Benzodiazepines

Alprazolam (Xanax), lorazepam (Ativan), clonazepam (Klonopin), diazepam (Valium), and others significantly impair driving. The effect is most pronounced in the first hours after a dose but can persist.

Z drugs and other sleep medications

Zolpidem (Ambien), eszopiclone (Lunesta), and zaleplon (Sonata) can impair morning driving, particularly in women, particularly with the higher doses, and particularly when sleep was less than 7 to 8 hours after taking the medication.

First generation antihistamines

Diphenhydramine (Benadryl) is a common one. Driving impairment from a 50 mg dose has been shown to be roughly equivalent to a blood alcohol level around the legal limit in some studies. The impairment is often not subjectively felt by the patient.

Antiseizure medications

Some antiseizure medications cause sedation, slowed reaction time, or vision changes. The effect is dose dependent and often worse in the first weeks of therapy.

Muscle relaxants

Cyclobenzaprine (Flexeril), carisoprodol (Soma), methocarbamol, and others cause significant sedation for many patients.

Some antidepressants

Mirtazapine and trazodone cause sedation. Tricyclic antidepressants can blur vision and cause orthostatic dizziness. SSRIs and SNRIs are generally lower risk but can cause dizziness or fatigue in some patients.

Some blood pressure medications

Most blood pressure medications do not significantly impair driving. Some can cause orthostatic dizziness, particularly when first started or when the dose is increased, especially in older adults.

ADHD medications and stimulants

Generally improve driving performance when prescribed for actual ADHD. Can impair driving when used at higher than prescribed doses or when used to compensate for sleep deprivation.

Cannabis containing products

Including some CBD products that contain THC. THC affects coordination, reaction time, and judgment, with effects that can persist hours after use.

What to do if you must take an impairing medication

• Avoid driving for the first several days of any new medication that may cause sedation.
• Avoid driving for several hours after a dose of any sedating medication.
• Avoid combining sedating medications, including with alcohol.
• Choose dosing schedules that put sedating effects during sleeping hours when possible.
• Ask your pharmacist about non sedating alternatives when an alternative exists.
• Be especially cautious in the first hours of the morning after sleep medications.
• Have a backup transportation plan if your medication situation is uncertain.

Driving and the older adult

Older adults are more vulnerable to medication side effects in general and to driving impairment specifically. Aging changes how the body processes many drugs. Vision and reaction time decline with age independent of medications. The combination can produce driving impairment that none of the individual factors would have caused. Family members noticing driving changes in an older relative should consider whether a medication review is appropriate before assuming it is age alone.

Where pharmacy fits

Free pharmacist consultations on any medication and its driving safety implications. We can identify which of your medications are most likely impairing your driving, suggest timing changes, and recommend alternatives when appropriate. Serving Hattiesburg, the Pine Belt, Central Mississippi, and South Mississippi.

When to call a pharmacist

• You are starting a new medication and want to know if it will affect driving.
• You take a sedating medication and have been involved in a recent near miss or accident.
• You take multiple medications that may stack to cause driving impairment.
• A family member is on multiple medications and you are concerned about their driving.
• You are using OTC Benadryl regularly during the day.
• You are pregnant or breastfeeding and on a sedating medication.

This article is for general information only and is not a substitute for personalized medical advice. Before starting or changing any medication, including over the counter products and supplements, talk with your pharmacist or physician about your specific situation.