The driver was weaving her car across lanes. She eventually veered off the side of the road and hit a child on a bicycle.
When the police arrived, they suspected she had been drinking. Not only had her driving been erratic, but she could barely communicate and had a hard time walking. They were puzzled, however, by the Breathalyzer test that came back negative.
At police headquarters she nearly fell off the chair. The police concluded that she was impaired not by alcohol but by the prescription anti-anxiety medicine she had been taking.
Millions of people drive under the influence of prescription drugs. There is no instant test that can tell if a medicine has made a driver unsafe. Certain computer programs can assess a driver’s ability to navigate (Journal of Studies on Alcohol and Drugs, March, 2009). Unfortunately, few police departments are equipped to administer and interpret such tests.
Physicians may not always tell patients not to drive while taking certain medications. More than 100 million prescriptions are dispensed annually for anti-anxiety agents like alprazolam (Xanax), clonazepam (Klonopin), diazepam (Valium) and lorazepam (Ativan).
They may carry a warning such as, “Until you experience how this medication affects you, do not drive a car or operate potentially dangerous machinery.”
It’s not just sedatives that impact driving skills. A medication for fibromyalgia called Lyrica is widely advertised on television. The announcer cautions viewers, “Don’t drive or use machinery until you know how Lyrica affects you.”
The trouble is that people are not good at assessing how prescription medications affect their driving ability. Ask anyone who has had several beers if he is safe to drive and the answer might well be “sure.” Sophisticated tests of reaction time and judgment could tell a different story.
Drug company warnings are not clear enough. The prescribing information for the stop-smoking drug Chantix, for example, warns:
“There have been postmarketing reports of traffic accidents, near-miss incidents in traffic, or other accidental injuries in patients taking CHANTIX. In some cases, the patients reported somnolence, dizziness, loss of consciousness or difficulty concentrating that resulted in impairment…in driving or operating machinery. Advise patients to use caution driving or operating machinery or engaging in other potentially hazardous activities until they know how CHANTIX may affect them.”
Very few people would be willing to take a drug that precludes driving, but Chantix is not the only problem.
Medications like Requip and Mirapex are prescribed for restless leg syndrome (RLS). Patients taking these drugs have fallen asleep while driving and ended up in accidents. Some had no warning signs of drowsiness and felt alert immediately before the event.
Even over-the-counter allergy medicines can be dangerous. Diphenhydramine (AllerMax, Benadryl) was found to have “a greater impact on driving than alcohol did” (Annals of Internal Medicine, March 7, 2000).
There are hundreds of drugs that can make drivers a menace on the roads. Doctors and pharmacists should tell patients “DO NOT DRIVE” when taking these medicines. Inconvenient, yes. Life-saving, quite possibly.