Amphetamines should not be used during flight
except in unusual situations (mostly military)
in which mission completion is paramount and
fatigue represents a greater hazard than drug
use during a critical, relatively brief, phase of the
flight.

A 35-year-old pilot with 63 hours flying time
was killed when he crashed while buzzing a
tavern at night. He had a blood alcohol level
of 200 mg % and a blood amphetamine level of
nine micrograms percent. A 27-year-old pilot
with 19.8 hours flying time was killed in an un-
explained accident. He had a kidney and liver
amphetamine level of 0.1 mg % and tissue amo-
barbital levels of 0.20 to 1.00 mg %. Causal
roles were not ascribed to amphetamine in either
accident but the frequent presence of more than
one drug is demonstrated.

The monoamine-oxidase inhibitors, which are
also psychic stimulants, are rarely indicated for
persons who are well enough to fly. Significant
side effects, particularly hypotension, blurred
vision and excitement, also make flying contrain-
dicated. The possible altered response to other
drugs and alcohol should be recognized for this
group.

Tranquilizers and Sedatives. In cost cases,
flying is contraindicated by a condition which re-
quires tranquilizers. However, experience has
shown that they are prescribed quite liberally
and without due concern for the patient’s occupa-
tion or the undesirable effects of these drugs.
While it may not be readily apparent, even the
nonsedating tranquilizers usually have some
measurable effects on alertness, judgment, effi-
ciency and over-all performance.

‘Sedatives have been used under controlled con-
ditions by the military to guarantee adequate
rest before flight and alertness during flight.
Secobarbital sodium, often used for this purpose
because it is considered a short-acting sedative,
has been found to have effects for up to eight or
nine hours when given in 200 mg doses under con-
trolled experimental conditions.

Pilot duties are contraindicated for 12 to 24
hours after the use of sedative agents.

A 50-year-old pilot with 108 hours of flying
time had a fatal accident when he departed with
one passenger on a VFR flight under IFR con-
ditions. He had blood levels of 0.7 mg % of
long acting barbiturate and 40 mg % of alcohol.

A 51-year-old pilot, with 1136 hours, and four
passengers were killed when their aircraft went
into a spin at low altitude and crashed. A blood
barbiturate level of “0.2 to 0.4 mg %”, blood
alcohol level of 8 mg %, COHb of 12% and
fatigue after a four hour flight are felt possibly
to have been additive and causal.

A 24-year-old pilot with 2203 hours was in-
volved in a fatal helicopter crash of undeter-
mined cause. He had a blood phenobarbital level
of 0.2 mg % which was not felt to be clinically
significant. The reason for drug use was not
determined.

A 49-year-old physician was known to use
narcotics, barbiturates, and tranquilizers. He had
lost his medical license. Erratic behavior had
been noted for over two years. He had passed
out while driving and had had several automobile
accidents. A relative, who stopped flying with
him, had considered reporting him to the FAA.
He had a fatal accident after a stall and spin.
He had blood levels of 3.54 mg % of pheno-
barbital and 0.95 mg % of meprobamate, a com-
bined effect near the stupor level.

A 49-year-old pilot with 100 hours of flying
time was killed when his plane dived into a
reservoir. He had been hospitalized for depres-
sion due to alcoholism two years before. He had
blood levels of 100 mg % of alcohol and 11 mg %
of bromide,

Attention is drawn here to the involvement of
multiple drug, alcohol and physiologic factors,
and the family (and sometimes local official)
apathy that is observed too frequently.

Cardiac Agents. Hypertension and most hypo-
tensive agents are disqualifying for flying duties.
While medication is the simplest treatment for a
physician to render, most authorities agree that,
where indicated, weight reduction is the treat-
ment of choice. A patient with benign essential
hypertension without demonstrable eye, kidney
or electrocardiographic changes may not require
medication if salt intake is restricted and a con-
trolled weight reduction program is instituted,
preferably with exercise. Thereafter, the patient
can probably fly safely.

Intermittent drug therapy is not indicated be-
cause of the long duration of effects, particularly
with reserpine.

Because of the common knowledge that drug
relief from disqualifying hypertension is avail-
able, a military medical evaluation center ana-





portant in flying, and are reduced at low blood
alcohol levels, but are most difficult to measure.
A significant decrement in performance is often
not seen at levels below 50 mg %.

A complete review of the literature on this sub-
ject is beyond the scope of this paper. The high
incidence of alcohol involvement in fatal acci-
dents and the reporting discrepancies were men-
tioned earlier. The incidence is clearly too high.
Further research is indicated to better identify
the legal level of intoxication with flying. From
a practical point of view, considering the high
percentage of human factors accidents, indi-
vidual variation of effects, the frequent presence
of other factors such as drugs and fatigue, and
residual effects, no alcohol level should be con-
sidered compatible with flying. Grounding for
three to four hours per drink is suggested as a
“rule of thumb” for most situations.

Education and, if unsuccessful, attempted en-
forcement of existing regulations should be used
to reduce the incidence of flying while under the
influence of ethyl alcohol.

PESTICIDES

The high accident rate in aerial application
and the high incidence of poisoning in the few
accidents investigated were mentioned earlier. We
have previously reported several of these cases.?°'*

We are disturbed that several cases of poison-
ing have been admitted to hospitals, and even to
university medical centers, and undiagnosed and/
or not treated with available effective drugs. In
extensive educational activities with the “ag” op-
erators and pilots, we discourage self-medication.
While their use of drugs to reduce symptoms and
increase tolerance to the pesticides is dangerous
and therefore contraindicated, it must be admitted
that most safety-minded aerial applicator pilots
know more about the symptoms of poisoning and
the correct drugs and dosages than does the
average physician.

For physicians who may be called upon to
treat any patient with exposure to insecticides,
an annual review of the signs, symptoms and
treatment is recommended. Purchase of the
Clinical Handbook on Economic Poisons is also
recommended (available from the Superintendent
of Documents, U.S. Government Printing Office,
Washington, D.C. 20402, for 55 cents.)

In cases of mild poisoning, miosis, rhinorrhea,
and salivation are seen in about 90 percent of the

cases; constriction of the chest is reported by
about 80 percent; and dimness of vision and
cough are noted by 60 percent. Some report head-
ache, fatigue, anorexia, nausea, increased perspi-
ration, dizziness, twitching, increased dreaming,
irritability and mood changes. In severe poison-
ing, all symptoms are increased with vomiting
and uncontrollable muscular twitching having
the largest proportional increase in incidence.
The most important signs are cyanosis, convul-
sions, coma, loss of reflexes, and loss of sphincter
control.

Diagnosis depends upon the signs and symtoms,
the label from the container, reliable informa-
tion (not from the patient), the blood choline-
sterase level, and, in poisoning by parathion and
its congeners, the urine paranitrophenol level.

Treatment, which is started before the labora-
tory values are received, consists initially of es-
tablishing an airway, artificial respiration, oxy-
gen and suction when necessary.

Atropine, given intravenously, is the initial
drug of choice. The success of treatment is di-
rectly proportional to the promptness of adminis-
tration and adequacy of dosage of atropine.

Atropine is of little or no value in the treat-
ment of poisoning by pesticides other than the
organophosphate compounds. It is absolutely
contraindicated for pentachlorophenol poisoning,
another insecticide which produces symptoms
similar to those of the organophosphates, and
may be contraindicated in chlorinated hydro-
carbon poisoning. The importance of the label
and reliable information in making the correct
diagnosis is therefore emphasized.

Atropine should be administered intravenously
in dosages of 1 to 2 mg (for mild cases) to 2 to
4 mg (for severe cases) every 5 to 10 minutes
until atropinization occurs (dry flushed skin,
pulse rate of 140 per minute, and pupillary dila-
tation).

One gram of 2-PAM chloride should be slowly
administered intravenously. Another 500 mg
should be given in one-half hour if muscular
weakness persists. This is a specific chemical
antidote which releases cholinesterase inactivated
by the phosphate ester but its effectiveness de-
creases after 24 hours. Best results are obtained
when 2-PAM and atropine are both given.

The clothing should be removed and the skin,
hair, nails and eyes should be decontaminated.



lyzes the urine of referred airmen for these agents.
Because of the likelihood of a reduction in G
tolerance with these drugs, particularly with the
ganglionic blocking agents, their use is of greater
concern in military airmen.

In civil aviation, medical certification may be
granted for pilots who have taken a hypotensive
agent (particularly thiazide diuretics) for a pro-
longed period and who have demonstrated good
control of a relatively stable condition with no
significant side effects. Such actions must, of
necessity, be on an individualized basis.

A 45-year-old pilot with 91 hours entered an
unexplained bank and dive just after take-off
and he and his passenger were killed. A 0.05 mg
% liver level of “quinine or quinidine” raises the
question of a possible medical condition under
treatment and inflight incapacitation.

Pilots have had pargyline and other drugs
prescribed simultaneously ; one such pilot has had
an accident due to alcohol.’ Flying is contrain-
dicated with pargyline and most of the agents
which augment its effects and pilots should be
advised of this by their physicians; all patients
should be warned of the possible combined effects.

Muscle Relaxants. These agents, with or with-
out analgesic and tranquilizer actions, cause suf-
ficient weakness, sedation and vertigo to contra-
indicate pilot duties within at least 12 hours after
their use.

Steroids. These compounds are often used sys-
temically for the relief of arthritic, allergic, der-
matologic and inflammatory conditions which
may not, in themselves, contraindicate the per-
formance of pilot duties. Flying is considered
contraindicated for three days after the systemic
use of steroids because of the possible mental
changes and other undesirable effects. The
topical use of these preparations is not expected
to compromise flying safety.

Drugs for Hyperuricemia, These agents are
frequently discussed but there is no unanimity of
opinion regarding their acceptability for use by
flying personnel. The authors are not opposed
to the supervised use of uricosuric agents by
asymptomatic pilots with hyperuricemia. Head-
ache and gastrointestinal effects, while undesir-
able, are not usually incapacitating. An attempt
should be made to determine the presence and
severity of these or other symtoms when these
patients are examined for medical certification.

The xanthine oxidase inhibitors are also re-
ported to be effective and relatively free from
side effects,

In metabolic diseases like hyperuricemia and
diabetes mellitus, where the treatment and not
the disease may be disqualifying for flying, pilots
and cooperative physicians will often shun treat-
ment. The relative hazards, both immediate and
long term, of the treatment vs. the untreated con-
dition must be considered. Long discussions have
resulted from such considerations but these are
equally inconclusive.

Anticholinergies. Anticholinergic compounds
are frequently used and occasionally found as-
sociated with aviation accidents and incidents.
Since they are frequently combined with seda-
tives and tranquilizers, their side effects can in-
clude, not only blurred vision and ataxia, but
sedation, muscle weakness and altered judgment.
Their use is contraindicated with flying.

And Finally, “The Pill”. There are approxi-
mately 21,000 active female pilots under the age
of 45. We do not know, nor will we probably
ever know, the number who take oral contra-
ceptive preparations. Several pilot-physicians
who have several patients on these medications
have expressed concern over the symptoms of
tension noted by “many” of their patients. While
there is insufficient evidence of significant unde-
sirable effects at this time to consider control on
their reporting or use by female pilots, we must
keep abreast of evolving knowledge on thrombo-
embolic, or other, problems with these products
and consider these data, age, past medical history,
and physical findings in the counseling and certi-
fication of these pilots.

ETHYL ALCOHOL

Everyone interested in aviation safety agrees
that drinking and flying do not mix and that
alcohol should intensify the effects of hypoxia.
However, despite many studies of the subject,
there is no generally accepted blood alcohol level,
or time after recovery, for the safe operation of
an aircraft. The degree to which alcohol in-
creases the effects of hypoxia is similarly incon-
clusive.

Nystagmic and EEG changes can be noted
after the blood alcohol level returns to zero.
Decrements in vision and hearing have been re-
ported at levels as low as 10 mg % (though for
abstainers and probably not realistic). Judg-
ment, comprehension and fine attention are im-


Half of Traffic
Accidents Tied
To Drugs’ Use

NORMAN — Over 50 per-
cent of traffic accidents in
the nation can be attributed
to the use of drugs, a case
officer for the Bureau of
Drug Abuse Control told a
University of Oklahoma
audience Thursday night.

J. W. Hand, a drug expert
appearing as the first speak-
er in OU’s public lecture se-
ries, discussed drug use and
effects. He has done exten-
sive undercover work among
drug users in Oklahoma.

Hand outlined types of
drugs, saying they include
depressants, stimulants and
hallucogenics.

Stimulants Listed

“Stimulants in the form of
pep pills,” he said, ‘don’t
really pep you up. They sim-
ply deactivate that part of
the brain that lets you re-
lax."

Hand listed alcohol, glue
sniffing and marijuana as
depressants which could
have some bizzare effects.
He said marijuana gives the
user a bright subjective out-
look while the object of re-
ality remains the same.

Hand said LSD, a halluco-
genic drug which has been
called ‘mind expanding,”
actually gives the user @
one-track mind.

‘The personal effects that
drugs may cause don't both-
er Hand as much as the
anti-social behavior that is
produced.

‘Abase Contagious

“[ really don't care if
someone wants to get high,””
he sald, ‘but I am_con-
cerned for the innocent who
might be involved.”

“We have found that drug
abuse spreads like a conta-
gious disease.” Hand said.
“It spreads through social
contact and many people
wish we would consider it a
health problem."”

‘The narcotics officer said
drug pushers will "go to any
means" to promote thelr

ucts.
Phe said that if the nation

“ to pot (marjjuana)"
out is exactly what it, in
fact, will do.

Use of Prescribed Drugs Is Becoming
A Factor in Cause of Traffic Accidents

By GERALD R. THORP
Of The Post-Dispatch Staff
‘THIRD OF A SERIES
‘One of the most puzzling in-
tangibles among basic causes
for motor vehicle accidents is
driver use of drugs.
Se
in driving
mince 78
fringe field for
investigation
by _medical- Dead
traffic experts
for many years,
but at this
point they gen- n

eally agree:
“We auill don’t
know enough Last Year
about it.”

Two separate arrests were
smade by St. Louis county police
im April in which the drivers

Drinking Dri

appeared to be intoxicated.
However, both registered zero
when given clinical tests that
‘would have indicated alcohol in
the blood.

“The driving of both men had
-antly erratic that it
‘was apparent something had in-
fluenced their normal behavior,”
said Sgt. Edward Willette who
is in charge of the county's
Traffic Safety Bureau.

Additional investigation dis-
closed that one driver was
“high” on illegal drugs he had
stolen, In the second case, the
motorist had been taking drugs
prescribed by @ physician for a
minor ailment

Robert B. Forney, research
professor at the University of
Indiana's Indianapolis campus,
told the Post-Dispatch: ‘We all
‘know that there is @ strong cor-
elation between drug use and

erratic driving. This 1s @ prob-
Tem that will become more in-
tense because in the modern
era nearly every driver at one
time or another will have had
occasion to take a. prescribed
drug, unaware of its possible
side effects.”

Dr. L. C. Norman, a British
authority in the field, wrote:
“The innumerable new drugs
which are being introduced week
by week. almost day by day.
make it impossible for the pa-
tient to know the side effects,

“Indeed, tragically, the doctor
does not’ always know them,
but what he does know he should
impart to his patient as a driv-
er... With antihistaminics, to
take just one example, the pa-
ent should be advised to give
imself a trial of the effects. If
a new antihistar

TURN TO PAGE 6, COLUMN §

More than half the drivers and pedestrians killed

in San Antonio, Texas, during the past nine years were drunk, according
to a study by Robert’ Hausman, MD. the county medical examiner. He
based his report on studies, most of which included complete autopsies,
of 301 drivers and pedestrians who were killed

Blood Alcohol: Iowa's deputy state commissioner of public safety,
James P. Hayes, suggested to a statewide lowa traffic safety conference
in Des Moines that a state law be passed fixing a minimum blood alcohol
level for determining whether a motorist is intoxicated. lowa law now
fixes no blood alcohol level as presumptive evidence, but evidence of
amounts of alcohol in the blood as shown by tests is admissible in court.
Hayes pointed out that both the American Medical Association and the
Iowa Medical Society recommend that 0.10 of 1% be considered pre-
sumption of intoxication.

Auto Toll: The National Safety
Council predicted that 1966 auto

Half of Fatal

accidents would cause the high-

est death toll in history. The toll
through the first 10 months of
this year, it said, was 43,110—9%
above the 39,610 in the first 10
months of 1965. In Washington,
the Insurance Institute for High-
way Safety estimated that drink-
ing may have been a factor in
half of the 4,920 traffic deaths

during October.

Car Accidents
Linked fo Drinking

By JOSEPH HEARST
Chicago Tribune Press Service
WASHINGTON — The issue of

building more safety into auto-
mobiles took a back seat Wednes-
day as a Congressional commit-
tee discussed drinking drivers.

Dr. Philp R. Lee, assistant
secretary for health ‘and sciem-
tific affairs of the Health, Educa-
tion, and Welfare Department,
told’ the House Commerce Com-
mittee alcohol is a major con:
tributing factor in fatal acci-
dents, involving both pedestri-
ans and vehicle occupas

He said hall of the fatal accl-
dents have some association with
alcohol. He said millions drive
after drinking and that his de-



AM 68-16

DRUG AND TOXIC HAZARDS IN GENERAL AVIATION

J. Robert Dille, M.D.
Stanley R. Mohler, M.D.

Approved by Released by
J. Rozsert Dux, M.D. P. V. Srecen, M.D.
Cuter, Crvm ArRoMEDICAL FeperaL Ai Surcron
Instirure

September 1968

Department of Transportation
FEDERAL AVIATION ADMINISTRATION
Office of Aviation Medicine



Symtomatic treatment should be continued for
24 to 48 hours.

A blood sample for cholinesterase determin-
ations should’ be drawn before 2-PAM is ad-
ministered.

No morphine, tranquilizers, or barbiturates
should be given.

Since there are over 55,000 trade name pesti-
cide products in the United States representing
formulations of over 300 different chemicals,
problem cases may be encountered. A telephone
call to the nearest Poison Control Center is ad-
vised for perplexing problems.

The chlorinated hydrocarbon insecticides vary
widely in chemical structure and activity. They
act primarily on the central nervous but the
exact mechanism of action is not known. They
also produce some gastrointestinal effects and, at
least in animals, liver and kidney damage. They
are stored in fat and released very slowly. The
fat levels are felt to be mostly inactive materials
but convulsions many months after exposure have
been noted in animals.

Signs and symptoms usually consist of head-
ache, nausea, dizziness, hyperexcitability, tremor,
and, classically with severe poisoning, convul-
sions which may be followed by coma.

Laboratory diagnosis is difficult. The insecti-
cide or its derivatives can be identified in body
fat, urine and stomach contents by properly
equipped laboratories. The electroencephalogram
may show bilateral synchronous spikes, spike and
wave complexes and slow theta waves. These
changes may persist for a few months after the
last exposure. A good history is important.

Treatment, 100, is less specific than for organo-
phosphate poisoning. Removal of the poison
from the skin or gastrointestinal tract, high
dosages of sedatives and, sometimes, calcium
gluconate are the principal effective measures.

CARBON MONOXIDE

Carbon monoxide constitutes up to 2.5 percent
of the volume of cigarette smoke and more in
cigar smoke. If the smoke of three cigarettes is
inhaled in rapid succession at sea level, a car-
boxyhemoglobin saturation of 4 percent may re-
sult. This can reduce visual acuity and dark
adaptation to the extent of the mild hypoxia of
8000 feet. Smoking at 10,000 feet can produce
effects equivalent to those seen at 14,000 feet
without smoking. The effects of smoking at
20,000 feet are equivalent to the effects otherwise
expected at 22,000 feet. With heavy smoking,
carboxyhemoglobin concentrations as high as 8
percent are possible.

While the adverse effects of smoking have been,
and should continue to be, included in airman
education material, this is not likely to be a deter-
mined cause of an aircraft accident. This is
because of the necessary combined effects and the
usual lack of objective evidence.

Carbon monoxide has been found as the cause
of death in both general aviation and air carrier
accidents with fire.

The greatest threat is from carbon monoxide
leaks into the cabin from worn or defective ex-
haust stack slip joints, exhaust system cracks or
holes, openings in the engine firewall, defective
gaskets in the exhaust manifold and defective
mufllers.

In one aerial application fatal accident, a 40%
carboxyhemoglobin level was found. In modi-
fying a light aircraft for crop dusting, the cabin
heater was removed and the exhaust aperture in-
effectively capped.

While this is a relatively rare cause of acci-
dents, it can be prevented by periodic inspection
of the exhaust manifold and heater assembly,
awareness of the early symptoms of poisoning
and use of a carbon monoxide detector.

REFERENCES

1, British Board of Trade: Medical Factor Studied in
Bellanca Crash. Aviation Week and Space Technology,
87:105, (December 11) 1967.

2. Ditre, J. R., and Morris, B. W.: Human Factors in
General Aviation Accidents. Aerospace Med., 38 :1063,
1967.

3. Dicue, J. R. and Smrrx, P. W.: Medical Advances in
Aerial Application Problems. Flying Physician, 9:6,
(October) 1965.

4, Harper, C. R., and Arpers, W. R.: Alcohol and Gen-
eral Aviation Accidents. Aerospace Med., 35 :462, 1964.
5, Mouter, 8S. R., and Harper, C. R.: Protecting the Ag
Pilot. Federal Aviation Agency Office of Aviation
Medicine Report 66-30, September 1966,
National Transportation Safety Board: Annual Re-
view of U.S. General Aviation Accidents Occurring in
Calendar Year 1966, November, 1967.

7. Smiru, P. W.: Unpublished data.

-


Some of the medications of greatest use and
concern, and some recent accidents involving
drugs, are discussed here.

Analgesics. Probably no over-the-counter drug
is used more often or more indiscriminately than
acetylsalicylic acid. Toxic effects are relatively
rare and are almost always associated with large
doses. However, gastrointestional hemorrhage,
acute renal failure, blood dyscrasias and idiosyn-
cratic reactions (such as urticaria and angioneu-
rotic edema) are possible. Hemorrhage, when it
occurs, is usually due to a competitive antagonism
with vitamin K and a decreased circulating
prothrombin. A reduced tolerance to hypoxia
has been found with salicylates, mostly because
of an increase in the metabolic rate.

Analgesic compounds containing aniline deriva-
tives may cause methemoglobinemia if used in-
discriminately. Excessive use of bromide-con-
taining compounds may cause psychosis or der-
matitis. Quinine-containing preparations may
cause vertigo, tinnitus, deafness or nausea.

Of greatest concern is the frequent combination
of analgesics, antihistamines and decongestants in
compounds which may be taken for analgesic
purposes only. The roles of these added in-
gredients are discussed below.

Antihistamines. Undesirable effects which are
possible with the use of antihistamines are drowsi-
ness, inattention, confusion, mental depression,
dizziness, decreased vestibular function and im-
paired depth perception.

Because of the adverse effects of these symtoms
on the safety of flight, airmen generally should
not take “short-acting” antihistamines during the
8 hours before flight or take the “long-acting”
preparations within 16 hours of flying.

Individual consideration should be given to al-
lergic patients who have taken the same drug
and dosage for long intervals with a good sym-
tomatic response and no noted side effects.

“Nonsedating” antihistamines (for example,
phenindamine tartrate) should be evaluated for
their suitability for safe use.

A 38-year-old pilot was killed in a crash of his
helicopter due to the improper operation of the
powerplant and flight controls. He had two
blood alcohol level determinations reported as
80 and 100 mg % and a “significant” level of an
antihistamine believed to be diphenhydramine.
The combined effects of these two agents are be-
lieved to have caused impaired efficiency and

judgment and are given as the cause of the ac-
cident.

Antihistamines have also been implicated in a
recently reported British accident.

Nasal Decongestants. Since these compounds
can occasionally be used to advantage topically
during flight (usually for the relief of a blocked
eustachian tube during descent), their proper use
in flight is not contraindicated. Indiscriminate
use of these compounds, particularly by the
systemic route, can cause tachycardia, nervous-
ness, tremor, incoordination and mydriasis with
visual disturbances.

Motion Sickness Medications. Several types of
drugs are used for the relief of motion sickness.
Scopolamine, a parasympathetic depressant some-
times used for this purpose, is effective but has
sufficient side effects to limit its use. Antihista-
mines are used widely but often cause drowsiness
and dizziness. The sedative antihistamines, such
as promethazine, are particularly likely to pro-
duce drowsiness. Cyclizine and meclizine also
can produce drowsiness and blurred vision may
occur with cyclizine. However, side effects are
Jess common with these two drugs. Barbiturates
have been used but are seemingly of. less value
and are definitely contraindicated during flight.

Most pilot trainees who become airsick will
have no difficulty by the tenth flight. There-
fore, cyclizine or meclizine may be temporarily
given for motion sickness before training is dis-
continued, but only under medical supervision,
after a test. dose, on dual flights and with the
consent of the flight instructor. Otherwise, the
use of these preparations during flight or within
8 hours to 24 hours (with meclizine) before flight
is generally contraindicated.

Amphetamines. Amphetamines diminish a
sense of fatigue, can delay its onset up to four
hours, and tend to force the body beyond its
natural capacities. Nervousness, impaired judg-
ment and euphoria are sometimes reported, par-
ticularly with overdosage or unusual suscepti-
bility.

Many patients find the stimulation produced
by amphetamines pleasant and complain when
the physician suggests discontinuance. They can
be habit forming and excessive use is common.

‘When amphetamines are taken in conjunction
with a weight reduction program, hypoglycemia
may be present. The effects of hypoglycemia are
additive to those of hypoxia.


DRUG AND TOXIC HAZARDS IN GENERAL AVIATION

Drugs and alcohol are frequently cited as major
causes of automobile accidents (Figure 1). Drugs
are rarely reported as a cause of aircraft ac-
cidents. This is due to the relatively infrequent
search for their presence and to unprecise defini-
tion of levels at which most of them begin to
impair pilot performance. Alcohol has been
found present in up to 35.4 percent‘ of fatal gen-
eral aviation accidents but a causal role has been
ascribed in only about seven percent.’ This dis-
crepancy is due to the absence of experimentally
determined and generally accepted blood alcohol
levels where pilot performance is significantly
impaired, In practice, the legal level of intoxica-
tion for driving an automobile is frequently used.
Most authorities agree that the 150 mg % level,
accepted in most states, is too high for safely op-
erating even an automobile. Most aviation au-
thorities agree that piloting an aircraft is more
complex than driving an automobile. The ef-
fects of combinations of alcohol and drugs are of
even greater concern.

While improved somewhat over previous years,
aerial application still has the highest accident
rates among commercial categories of aviation.
Evidence of pesticide poisoning has been found
in about one-third of fatal aerial applicator ac-
cidents, but on two small samples. Here, again,
the level at which a causal role should be assigned
is uncertain.

Carbon monoxide is the only other toxic ma-
terial which is occasionally found, and frequently
discussed, in general aviation. It is the deter-
mined cause of about three fatal accidents per
year; most are due to faulty exhaust manifolds
and heater assemblies. Carbon monoxide from
smoking tobacco products can significantly affect
hypoxia tolerance and night vision but this is
rarely, if ever, found as an accident cause.

Toxic products of combustion of cabin interior
materials and electrical insulation are primarily

Presented at the Air Medics and Flying Physicians Associa-
tion program, Texas Medical Association meeting, Houston,

May 2, 1968.
23822

of concern in air carrier operation and will not
be discussed here.

DRUGS

Drug usage in this country is almost universal
and apparently increasing each year. Many
potent drugs can be purchased over the counter;
others are prescribed by physicians who do not
inquire about or understand the demands of vari-
ous occupations; and still others are passed
around by well-meaning relatives, friends and
neighbors.

It is assumed that drugs have frequently been
taken by victims of general aviation accidents but,
their presence is rarely detected and, even if it is,
rarely warrants assignment of a causal role bas
upon present knowledge. A previous report?
cited two cases where ATR pilots with 3000 and
8000 hours had human. factors accidents and liver
barbiturate levels of 0.7 mg % and 0.4 mg %. One
of the compounds taken also contained d-am-
phetamine. Despite known possible effects on
judgment of both drugs, no causal role was felt
assignable.

All known “side effects” are now routinely
listed for every drug. The problem lies in pre-
dicting the occurence of these undesirable effects.
One approach, the military one, is to ban the use
of all drugs by aircrew members. This is
neither practical nor enforceable in civil aviation.
Supervised test doses are useful to determine in-
dividual responses. The fact that the condition
for which the drug is taken may, in itself, con-
traindicate flying should be remembered. The
fact that performance with drug-relieved sym-
toms may exceed performance with unrelieved
symtoms (but not performance without symtoms
or drugs) must also be considered.

Until more is known, a cautious approach to
drug use by airmen is urged. Studies of drug
effects on the performance of aviation tasks and
expanded investigation of aircraft accidents are
expected to provide useful information.



Qualified requestors may obtain Aviation Medical Reports from Defense Documentation
Center. The general public may purchase from Clearinghouse for Federal Scientific and
‘Technical Information, U.S. Dept. of Commerce, Springfield, Va. 22151