Stimulants & Sleep Aids in Military Aviation
Chemical stimulants and sleeping aids have a long history of use in improving performance in military personnel. The first pharmacologic stimulant, Amphetamine, became available by prescription in 1937. It was used in WWII by the Japanese and Germans of the Axis Powers and the British on the Allied side. The American military apparently did not have widespread access to the medication and therefore it was not used by U.S. Forces. Following the war, however, the use of stimulants was studied extensively and demonstrated appealing results.
In multiple studies using non-fatigued volunteers, performance in reaction time, hand-eye coordination, and most other mental tasks improved. Intentionally sleep-deprived individuals performed significantly better with stimulant use than the fatigued control groups. Additionally, Amphetamine proved a good medication to treat motion sickness in space. Eventually, in 1960 the United States Air Force sanctioned use of Amphetamine as a counter-fatigue measure in flight operations. The medication was used widely by USAF and Army aircrew during the Vietnam Conflict.1
Today, American and other nations’ armed forces use more modern stimulants and sleep aids to improve performance in combat. The policy to use these medications, however, has not always won unanimous support from military leadership. In 1992 Air Force Chief of Staff Gen. Merrill A. McPeak banned the distribution of amphetamines to aircrew, though he admitted that his decision was not based on science but only his own personal experiences as a pilot. The practice was reinstated by the USAF in 1996 when Gen McPeak left his position as USAF Chief of Staff.2 In the aviation community, these meds are often better known as ‘Go’ and ‘No-Go’ pills.
Use of these drugs is not without controversy. In 2002, the friendly fire Tarnak Farms incident, in which a U.S. Air National Guard (ANG) F-16 dropped a 500 lbs laser-guided bomb on a Canadian light-infantry unit erupted a debate after the pilot and his lawyer argued that stimulants provided by the Department of Defense were primarily responsible for the incident. There has been no shortage of eye-grabbing headlines ran by NBC, ABC, the New York Times and many other news organizations about the military drugging its soldiers, sailors, and airmen. After the book ‘No Easy Day‘ was published describing the operation in which Osama Bin Laden was killed in May 2011, many critics focused on the SEAL’s description of Ambien and the editorials and talking heads were back.
Although sensationalized media reports often paint a picture of Commanders pushing medications on unwilling soldiers and aviators to extend their physiologic limits, in fact use of these medications is highly controlled in use and very limited in scope. In the USAF, three sleep aids (temazepam aka Restoril, zolpidem aka Ambien, & zaleplon aka Sonata)and two stimulants (dextroamphetamine aka Dexedrine & modafanil aka Provigil) are approved for use by certain aircrew in particular operational situations. All aircrew must ‘ground-test’ these medications during their training in order to ensure they do not have any unexpected adverse effects. If they do suffer a side effect, their medical record is flagged that they are not cleared to use this particular medication.
Use of these medications by military personnel is actually more highly controlled and limited than their civilian counterparts. If you as the reader are not a pilot or other military member on flying status, you can likely go to your doctor at any point and request a prescription for Ambien. If a military pilot requests the same medication to be used to reset the circadian clock for expected jet lag after long air travel, they must be temporarily disqualified from flying status until use of the medication has ceased. This is considered a ‘clinical use’. In operational settings, during combat deployments however, pilots can use sleeping aids to assist with day sleep when needed. Every regulation, memorandum, and piece of military literature on the topic of battling fatigue emphasizes the use of NON-PHARMACOLOGIC means first and reserve prescription chemical formulations as a last resort when the mission requires performance in light of unavoidable fatigue. This is the consequence of warfare. Fatigue is even an unavoidable consequence of civilian flying operations. As the NTSB has recognized the role of fatigue in aircraft mishaps, they have recommended permitted use of sleep aids by commercial pilots as a means of preventing future accidents.
- See the previous post on strategies pilots can use to combat fatigue without the use of prescription medications.
In USAF fighter pilots and bombers, use of the stimulants Dextroamphetamine and Modafinil are only approved for specific long-duration sorties in very particular aircraft in which a pilot may be alone or unable to stand up and move. In order for these medications to be used, a significant amount of paperwork must be submitted and approved at a high level of command. It is also important to consider that the dosages used by pilots and operators are very low and that tens of thousands of American children take significantly higher doses just to be able to complete their homework every evening (with considerably less oversight by their parents and physicians!). Use of both sleep aids and stimulants when approved is actively evaluated and managed by the unit’s flight surgeon. If any signs of abuse or adverse effects are reported, use is immediately suspended until further details can be elucidated.
MEDIA SETS UP USAF PILOTS TO DISCUSS GO-PILLS
In this day and age where drones, night-vision-goggles and other technologies have turned warfare into a 24 x 7 x 365 event, fatigue will continue be a significant limiting and possibly even deciding factor in determining who will win a particular battle or war. In light of the myriad controls put in place to limit the negative effects of chemical counter-measures, the benefit and advantage that our military’s mission enjoys from them cannot be understated. Below are a few results from medical studies stating the effectiveness of these medications.
MEDICAL STUDIES DEMONSTRATING EFFECTS OF SLEEP AIDS ON PERFORMANCE
- 1993 Study on Effects of Ambien:
RESULTS: The use of hypnotics to optimize rest periods during sustained operations could be of help to military personnel. Zolpidem, an imidazopyridine hypnotic, was evaluated for its residual effects on daytime wakefulness in 12 subjects belonging to ground air force personnel and 12 navy fighterpilots. In this controlled double blind crossover study, each subject randomly received zolpidem 10 mg, flunitrazepam 1 mg or placebo, in three separate sessions, 1 week apart at 10 p.m. or 1 a.m., respectively. The absence of residual effects after zolpidem intake was attested by subjective assessments, psychomotor tests (including a simulated flight), and EEG analysis showed that this hypnotic could be considered for operational use.3
- 2009 Literature Review on the Effects of Ambien as Counter-Fatigue in Aircrew:
RESULTS: Pilot fatigue is a significant problem in modern aviation operations, largely because of the unpredictable work hours, long duty periods, circadian disruptions, and insufficient sleep that are commonplace in both civilian and military flight operations. The full impact of fatigue is often underappreciated, but many of its deleterious effects have long been known. Compared to people who are well-rested, people who are sleep deprived think and move more slowly, make more mistakes, and have memory difficulties. These negative effects may and do lead to aviation errors and accidents. In the 1930s, flight time limitations, suggested layover durations, and aircrew sleep recommendations were developed in an attempt to mitigate aircrew fatigue. Unfortunately, there have been few changes to aircrew scheduling provisions and flight time limitations since the time they were first introduced, despite evidence that updates are needed. Although the scientific understanding of fatigue, sleep, shift work, and circadian physiology has advanced significantly over the past several decades, current regulations and industry practices have in large part failed to adequately incorporate the new knowledge. Thus, the problem of pilot fatigue has steadily increased along with fatigue-related concerns over air safety. Accident statistics, reports from pilots themselves, and operational flight studies all show that fatigue is a growing concern within aviation operations. This position paper reviews the relevant scientific literature, summarizes applicable U.S. civilian and military flight regulations, evaluates various in-flight and pre-/postflight fatigue countermeasures, and describes emerging technologies for detecting and countering fatigue. Following the discussion of each major issue, position statements address ways to deal with fatigue in specific contexts with the goal of using current scientific knowledge to update policy and provide tools and techniques for improving air safety.4
MEDICAL STUDIES DEMONSTRATING EFFECTS OF STIMULANTS ON PERFORMANCE
- 2000 Double-Blind, Placebo Controlled Study on 6 Helicopter Pilots:
RESULTS: Modafinil attenuated sleep deprivation effects on four of six flight maneuvers, reduced slow-wave EEG activity, and lessened self-reported problems with mood and alertness in comparison to placebo. The most noticeable benefits occurred between 0330 and 1130 hours, when the combined impact of sleep loss and the circadian trough was most severe. The most frequently observed drug side effects were vertigo, nausea, and dizziness. These could have been related to: 1) the motion-based testing, 2) the use of a simulator rather than an actual aircraft (i.e., “simulator sickness”), and/or 3) the administration of more than 400 mg modafinil.5
- 2008 Study Comparing Caffeine and Two Prescription Stimulants:
RESULTS: Prolonged sleep loss impairs alertness, vigilance and some higher-order cognitive and affective capacities. Some deficits can be temporarily reversed by stimulant medications including caffeine, dextroamphetamine, and modafinil. To date, only one study has directly compared the effectiveness of these three compounds and specified the doses at which all were equally effective in restoring alertness and vigilance following 64 h of wakefulness. The present study compared the effectiveness of these same three stimulants/doses following a less extreme period of sleep loss (i.e., 44 h). Fifty-three healthy adults received a single dose of modafinil 400 mg (n = 11), dextroamphetamine 20 mg (n = 16), caffeine 600 mg (n = 12), or placebo (n = 14) after 44 h of continuous wakefulness. After 61 h of being awake, participants obtained 12 h of recovery sleep. Psychomotor vigilance was assessed bi-hourly during waking and following recovery sleep. Relative to placebo, all three stimulants were equally effective in restoring psychomotor vigilance test speed and reducing lapses, although the duration of action was shortest for caffeine and longest for dextroamphetamine. At these doses, caffeine was associated with the highest percentage of subjectively reported side-effects while modafinil did not differ significantly from placebo. Subsequent recovery sleep was adversely affected in the dextroamphetamine group, but none of the stimulants had deleterious effects on postrecovery performance. Decisions regarding stimulant selection should be made with consideration of how factors such as duration of action, potential side-effects, and subsequent disruption of recovery sleep may interact with the demands of a particular operational environment.6
- From 2010 Study Surveying 29 Deployed F-15 Strike Eagle Aircrew:
RESULTS: Surveys were completed for 111 sorties averaging 7.6 h in duration. Stimulants were used on 35% of sorties an average of 2.8 h after takeoff. Stimulant use was associated with a decrease in in-flight and postflight fatigue without significant differences in postflight symptoms. Sorties airborne during the circadian trough, longer sortie durations, and preflight hypnotic use displayed statistically significant associations with in-flight stimulant use.7
4. Caldwell JA. Aerospace Medical Association Fatigue Countermeasures Subcommittee of the Aerospace Human Factors Committee. Fatigue countermeasures in aviation. Aviat Space Environ Med. 2009 Jan;80(1):29-59.
5. Caldwell JA. A double-blind, placebo-controlled investigation of the efficacy of modafinil for sustaining the alertness and performance of aviators: a helicopter simulator study. Psychopharmacology (Berl). 2000 Jun;150(3):272-82.