5 Dangerous Rxs for Drivers

Driving under the influence of prescription drugs may be just as dangerous as driving under the influence of alcohol.

Some medications may cause impairments such as drowsiness, slowed reaction times, and coordination difficulties. Similar to alcohol, these side effects can directly affect a patient’s ability to drive safely.

“Many drivers think that the impairing effects of medicines only occur when they are used excessively, or taken in excess, but that is not the case,” said Tanya Smyth, a road safety researcher from Queensland University of Technology. “Drivers are unable to accurately self-assess their impairment when taking medication and are overconfident in assessing their abilities.”

Pharmacists can leverage their position in the community to verbally warn patients about the dangers of driving while taking certain prescription medications.

“Get to know your pharmacist,” the FDA advises patients on its website. “Ask the pharmacist to go over your medicines with you and to remind you of effects they may have on your ability to drive safely.”

Here are some medications that may impair drivers:

1. Antidepressants and Antianxiety Agents

Clinical depression affects about 14.8 million US patients—or about 6.7% of the total adult population—while anxiety disorders affect approximately 3.3 million Americans.

Many prescription medications that are used to control the symptoms of either condition, such as selective serotonin reuptake inhibitors (SSRI), affect the brain and central nervous system (CNS), which can impair a driver’s motor skills, reaction time, or judgment in turn.

Taking 10 mg of diazepam (Valium), for example, can cause impairment similar to having a blood alcohol content (BAC) of 0.10%, which is above the legal limit for driving in all 50 states.

2. Antihistamines

With respect to the potential for driving impairment, the most concerning thing about antihistamines is the threat of anticholinergic cognitive issues that often accompany this drug class.

Although OTC medications like Claritin, Allegra, and Zyrtec are now manufactured as “non-drowsy,” it is a common misconception among patients that all antihistamine medications are non-drowsy, which may lead them to forgo reading the drug label.

Pharmacists are often asked which is the best OTC remedy to treat seasonal allergies, and this common question presents a good opportunity to counsel patients on the potential for impairment while driving.

3. Antihypertensives

With their hypotensive properties, antihypertensives are associated with side effects such as lightheadedness, dizziness, and fatigue that can all hinder driving performance.

Additionally, beta-blockers and sympatholytic drugs like clonidine, guanfacine, and methyldopa may cause sedation, confusion, or insomnia.

Pharmacists can counsel patients about the possibility that antihypertensive drugs, including those that can cause electrolyte imbalance, could affect their driving performance.

4. Antipsychotics

Nearly all antipsychotic agents have a high potential to impair driving performance through various CNS effects.

These medications generally have 3 side effect profiles—sedation, anticholinergic effects, and extrapyramidal effects—that can directly affect a patient’s ability to drive. Pharmacists and patients alike need to be aware of these profiles.

5. Benzodiazepines

Most health care professionals agree that benzodiazepines are overprescribed across the United States, which means that many patients are at risk of having driving impairments that could prove dangerous. Relevant side effects include impairments in vision, attention, and motor coordination.

Patients should be prescribed evening doses of the shortest-acting hypnotics whenever possible, as studies have shown that long-acting benzodiazepines impair psychomotor function the following day.