ASLEEP AT THE WHEEL

AH, spring! The recent warmer temperatures are prompting some of us to reach for our tennis rackets, golf clubs and gardening tools, as others of us reach for boxes of tissues and packages of antihistamines. But for the 39 million Americans who suffer red and swollen eyes, stuffed noses, scratchy throats and sneezing fits in response to the budding crocuses, cherry blossoms and lawn grasses, spring is misery, thanks to hay fever and other seasonal allergies.

Now, you may be asking, why is she writing about allergies in an automotive column? Because some allergy and cold medications, both prescription and over-the-counter, can cause enough drowsiness and dulled reaction that they are a least as bad as, if not worse than, driving under the influence of alcohol.

That’s the conclusion of a study published yesterday in the medical journal, Annals of Internal Medicine. Each driver was tested once after taking an antihistimane containing diphenhydramine commonly found in medications such as Benadryl or fexofenadine, a so-called second-generation allergy medication, such as in the prescription drug Allegra.

The 40 same drivers, aged 25-44, all of whom had previously used antihistamines to treat their allergies, also were tested after being given alcohol or plain water doctored to smell and taste like alcohol.

Driving ability was compared in a multi-million dollar driving simulator, much like the flight simulators used to train pilots. The simulator, funded in part by the federal government, is housed at an old B52 bomber base now part of the University of Iowa campus. The simulator measures performance 30-60 times per second. Drivers were measured on how well they matched the varying speed of the virtual vehicle in front of them on a winding, two lane country road, how well they stayed in their lane, and how well they responded to virtual life-threatening emergencies. Everything was videotaped by four cameras, one each recording faces, feet, steering wheel and over-the-shoulder.

Recently, I viewed some of the tapes. One driver on diphenhydramine, fell asleep at the virtual wheel, drove into the oncoming lane, and got killed by a virtual 18-wheeler. His comment? I always wondered what it would be like to fall asleep at the wheel and not get killed.

Another driver, a woman, also on diphenhydramine, did not fall asleep, but her reactions were so dulled that she drove straight off the road on a sharp curve, into a virtual crash.

Drivers tested after being legally drunk tended to drive too closely to the virtual vehicle in front of them and have less steering control meaning they veered erratically into the shoulder or across the center divider into oncoming lanes, but their reaction time to virtual crashes was quicker than with diphenydramine, the sedating allergy medication.

The same subjects tested after the placebo and after receiving non-sedating Allegra, did the best, and their results were virtually (pardon the pun) statistically identical. Although there are laws on the books in every state against drunk driving, only 26 states have laws restricting the use of medications which impair driving. In the northeast, Rhode Island, Vermont and Connecticut do. New York, New Jersey, Massachussets, Pennsylvania do not.

And, as indicated by the woman tested after taking diphenhydramine, not being drowsy is not an indication that it is okay to drive. Even if you do not feel drowsy after taking an antihistamine or alcohol, you still may be impaired, said Dr. John Weiler, a professor of internal medicine at the University of Iowa and the study’s lead researcher. His conclusion? Second-generation antihistamines containing fexofenadine, such as Allegra, do not appear to cause impairment in driving performance.

Without getting too medical technical, the new allergy ingredient does not get into the brain, only into the bloodstream. Alchohol and diphenhydramine get into the brain.

So, do not ignore those tiny, almost unreadable warnings on the back of the drugstore packages or on the prescription bottle. Do not drive or operate other heavy machinery while taking allergy or cold medications that impair your judgment.