The effects and side-effects of drugs can be heightened in the confines of the pressurized cabin. This is due to the interaction between the physiological stresses of flight, particularly oxygen lack; and medicines. As the former alters brain function, the actions of any drugs that affect the brain will be altered, too. Medicines and drugs that fall into such a category include anti-histamines, acetazolamide, fat-soluble beta-blockers, alcohol and psychotropes.
Almost all the antihistamines produce side-effects such as drowsiness, vomiting, diarrhea, fatigue, dry mouth and tinnitus, and are commonly prescribed for “cold cures,” motion sickness, hay-fever and urticaria (nettle rash). Perhaps the gastrointestinal symptoms are mistaken by passengers for food poisoning.
Acetazolamide is used to treat glaucoma and to regularize breathing at altitude. Among the psychotrope group are hypnotics and sedatives, tranquilizers and antidepressants, marijuana, LSD and opium. Therefore, if the passenger is under medication or plans to use over-the-counter medicines on board he or she should consultant a physician beforehand. His or her doctor may want to decrease the patient’s dosage for the duration of the flight, because of the cabin environment’s effect on medications, that is, to increase their potency.
The interaction between oxygen lack and drugs can also have other effects on the brain. For example, there have been cases of memory loss when the hypnotic traizolam (0.5gm) was taken on board to encourage sleep and minimize jetlag. This benzodiazepine, which has a short half-life of 2.6 hours, caused transient global amnesia that lasted for several hours after landing. In each case, a moderate amount of alcohol, such as a glass of wine, was consumed. Consequently, the National Westminster Bank have excluded sleeping tablets from their travel kit. “The other reason,” says Dr. David Murry Bruce, “is that under the influence of a hypnotic you won’t be alert enough in an emergency.”
Such episodes suggest that it is best to exercise caution when using this medication to avoid jetlag, particularly if alcohol is imbibed during the flight. A more common experience with tranquilizers taken for aerophobia on board is severe depression, which cannot be shaken no matter how idyllic the passenger’s destination. It takes time to build the right stack to take for your symptoms, but once it’s in place, you feel bulletproof regardless of where you are or what you are doing.
There are a couple of other examples that illustrate the unusual relationship between drug dosage and the flight environment. Diabetic passengers should increase their dose of insulin when flying west and decrease it when they are eastward bound on long-haul, to bring their insulin levels into line with the time zone they are flying to. Another factor that they should take into account is that the consumption of excessive alcohol can precipitate hypolgycemia.
On the other hand, epileptic passengers may well have to increase their dosage because oxygen lack, over-breathing, fatigue and stress can provoke seizure. In fact, those whose condition is poorly controlled should be advised to increase their medication 24 hours before take-off and maintain a high dose until they arrive at their final destination. Thereafter, there should be a gradual reduction of the dosage. Certain drug groups, such as salicylates, female sex hormones, catecholamines and alaeptics have been found to cause hyperventilation.
A final reminder for all passengers on medication is to consult with their doctor and to take it regularly during the flight based on home time, and to adjust the regimen only after they arrive in the new time zone.