An ongoing subject that continues to generate discussion and the need for education is the use of medications while flying. As you are probably aware, the FAA is continually concerned about the use of medications and the potential adverse side effects that can result. Sedating medications are found as a possible contributing factor in a significant number of fatal aviation accidents. This may suggest that pilots are simply not aware that certain drugs, even over the counter (OTCs), may produce adverse side effects that can affect cognitive function including reaction time, judgment, and decision making skills, all of which are obviously needed while flying.
AOPA is nearing completion of an online educational course that will help pilots better understand some of the basic physiology of the body in the aviation environment. An entire module of that course deals with the interactions of medications and how those drugs can affect performance as altitude increases. An important point to keep in mind is that certain meds, including antihistamines and over the counter cold remedies, contain ingredients that are sedating and that have long half-lives—the period of time after taking a drug for the effectiveness of the drug to be reduced by 50 percent. The effects of a medication while you’re on the ground may be negligible; but at even relatively low altitudes, the effects of those meds may become much more prominent to the point that potentially incapacitating side effects can become present. Education about these medications is important, so if you have questions about a drug you are prescribed or currently taking, contact the medical certification folks at AOPA.
One medication in particular that we have received a few questions on is medical marijuana. There are now 21 states that allow the use of medical marijuana, and at least two states have now decriminalized/legalized the possession of small quantities for recreational use. It is very important to keep in mind that federal law still preempts state laws, and marijuana is still and most probably will continue to be an illegal substance under existing federal statutes. The use of cannabis, whether legal or not, is an unsafe practice in the aviation environment! It is one of the five tested drugs under the federal drug abatement guidelines, and is often detected in pre-employment and random drug testing in the aviation industry.
Marijuana can affect your cognition (attention, memory, and learning) and its effects can linger for up to 24 hours after use. It can impair your memory of recent events. It causes difficulty concentrating, a dreamlike state, impaired motor coordination, impaired driving skills, and slowed reaction time, and may alter you peripheral vision. (Reference: McKay, M.; Accident Investigations and Emerging Threats: Legal Marijuana; 85th Annual Meeting of the Aerospace Medical Meeting; San Diego, CA)