Impairment from medication, particularly over the counter (OTC) medication, has been cited in a number of accidents in general aviation.
A 2011 study from the FAA’s Civil Aerospace Medical Institute (CAMI) Toxicology Lab found drugs and medications in 570 pilots from 1,353 total fatal pilots tested. That’s 42% of the pilots who died in accidents.
Most of the pilots with positive drug results, 511 — or 90% — were flying under CFR Part 91.
Some of the most common, potentially impairing medications are antihistamines. These allergy medications can have powerful sedating effects, so much so that the primary offender, diphenhydramine (known by most as Benadryl), is often used as an OTC sedative and is the sedating agent in most PM pain meds.
According to an NTSB study, sedating antihistamines are the most commonly detected medication in fatal accidents.
Cardiovascular drugs are also commonly present in fatal accidents. The majority of medications used to treat high blood pressure are safe to use while flying. For other cardiac conditions, it is important that you check with your AME to ensure that you are not using an unsafe (and prohibited) medication.
Some less common impairing drugs include antidiarrheal drugs (some contain opioids), anti-seizure drugs, some smoking cessation drugs, and some antidepressants.
For many of these drugs, there are options that are not impairing or disqualifying if you work with your primary care doctor or AME. If you suffer from allergies, you might use loratadine instead of diphenhydramine, for example.
What to Look For
The Food and Drug Administration (FDA) requires standard labeling for all OTC medications. These standard labels indicate the active ingredients, directions for use, and highlight potential side effects like drowsiness.
Still confused? The FAA has released a new OTC medication guide, which you can download here.
The guide provides pilots with a list of medications that are generally safe when used to treat a common ailment (GO) and those that are not (NO-GO).
It also includes a Do Not Issue/Do Not Fly section.
You can also find good information on drugs through trusted government sites like the National Institute of Health’s Medline site at MedlinePlus.gov. This site lists both generic and trade names along with side effects and warnings for almost every drug out there.
How long should you wait after taking one of these medications?
If you have to take a disqualifying or impairing medicine, how long should you wait before resuming flying?
Every medicine is different, but a good rule of thumb is five times the half life of the medication. The easy way to determine this is through the dosing interval. If a medication says to take it four times a day, the dosing interval would be six hours. That means the wait time after the last dose would be 30 hours (6 hours x 5 = 30 hours).
Other medications may have longer or shorter intervals which is why it’s important to talk to your AME, FAA officials advise.
As a pharmacology professor once told us in school, no medication, NONE, is without side effects (he added that aspirin was close but it would make little holes in your stomach). There is no question that antihistamines produce impairment to some degree, NO QUESTION ABOUT IT, and I always warm my patients about using caution while driving or operating any type of machinery while taking antihistamines. Can some pilots fly successfully while on antihistamines? Do some pilots fly safely after drinking alcohol or smoking weed? Absolutely, but why take a chance to see if you are one of them or not? Not me!!
The point seems to be CAMI is not in many cases science or evidence based. Instead, they take the position anything that could potentially have any affect on flying is a basis to not fly, which cases damage.
The irony of this article is that it seems to actually suggest the opposite of what their conclusions are.
Being tired or fatigued for example has a huge impact on flying, yet there is much less focus on that than say if someone is taking an antidepressant.
What the other commenters said.
Please tell me that NTSB and the aeromedical services branch have people who understand statistics – because this article – if it’s taking material from them – suggests they don’t.
There’s an old test that gets run on doctors from time to time, and almost all of them fail it. It runs, “If a test for an illness always detects the disease but has a 1% false positive rate, and 0.5% of the population has the disease, then if you test positive, what is the probability that you have the disease?” Most commonly doctors will guess 99% (1 minus the false positive rate). Actually, it’s about 33% – that is, it’s still 2 out of 3 that you do NOT have the disease.
Similar issue here. If 25% of pilots are taking antihistamines, and the drugs are present in 10% of fatal accidents (not all drugs in fatal accidents were antihistamines), then antihistamine-taking pilots are LESS likely than average to be in a fatal accident, and the advice is the polar opposite of correct.
Correlation is not causation. Is it possible that it’s so commonly found because it’s so commonly used? If so, then consider that detectable levels and levels which impair some/many/most/all users needs to be considered. Not everyone suffers enough cognitive impairment from these medications to be detectable in their performance, and others’ impairment varies with everything from their metabolism to their body mass.
While it’s good to warn people of potential issues, the scare-tactic of implying that 42% of accidents had OTC allergy meds as a contributing cause is nothing more than sensationalism. It could be the primary reason for impairment leading to an accident for one or some pilots out of the sample group, but the burden of proof is not even remotely approached in this article.
I’m sure some enterprising lawyer will find a family looking to unload responsibility for an accident and cash in with a lawsuit against a pharmaceutical manufacturer.
This seems to imply causation without any data supporting that conclusion.
90% of the accidents were Part 91. What percent of all accidents are part 91?
42% of pilots who had fatal accidents tested positive. What percentage of all pilots would test positive?
Both of those numbers would seem about right for all pilots. Maybe someone with hard data can provide some insight.